Phenotypic Profiling and Molecular Mechanisms in Hyperparathyroidism-jaw Tumor Syndrome

Context Hyperparathyroidism-jaw tumor (HPT-JT) syndrome is a heritable form of primary hyperparathyroidism caused by germline inactivating mutations in CDC73 encoding parafibromin and is associated with an increased risk of parathyroid cancer. There is little evidence to guide the management of patients with the disease.

(1) Characterize the natural history of HPT-JT, (2) correlate genotype and histology of parathyroid tumors with parafibromin immunostaining, (3) understand molecular changes downstream to CDC73 loss. Design Retrospective study of patients with HPT-JT syndrome (genetically confirmed or affected first-degree relatives). Independent review of uterine tumor from 2 patients and staining for parafibromin on parathyroid tumors from 19 patients (13 adenomas, 6 carcinomas) was performed. RNA-sequencing was performed in 21 parathyroid samples (8 HPT-JT-related adenomas, 6 HPT-JT-related carcinomas, and 7 sporadic carcinomas with wild-type CDC73).

We identified 68 patients from 29 kindreds with HPT-JT with median age at last follow-up of 39 [interquartile range, 29-53] years. A total of 55/68 (81%) developed primary hyperparathyroidism; 17/55 (31%) had parathyroid carcinoma. Twelve of 32 (38%) females developed uterine tumors. Of the 11 patients who had surgical resection for uterine tumors, 12/24 (50%) tumors were rare mixed epithelial mesenchymal polypoid lesions. Four of 68 patients (6%) developed solid kidney tumors; 3/4 had a CDC73 variant at p.M1 residue. Parafibromin staining of parathyroid tumors did not correlate with tumor histology or genotype. RNA-sequencing showed a significant association of HPT-JT-related parathyroid tumors with transmembrane receptor protein tyrosine kinase signaling pathway, mesodermal commitment pathway, and cell-cell adhesion.

Multiple, recurrent atypical adenomyomatous uterine polyps appear to be enriched in women with HPT-JT and appear characteristic of the disease. Patients with CDC73 variants at p.M1 residue appear predisposed to kidney tumors. Clinical Trial number

heritable primary hyperparathyroidism, CDC73, parathyroid cancer, hypercalcemia, multi-gland disease

Primary hyperparathyroidism (PHPT) is the third most common endocrine disorder and the most common cause of hypercalcemia in the outpatient setting (1, 2). Although no reliable evidence exists, approximately 10% to 15% of PHPT is assumed to consist of heritable forms of the disease (3, 4). Hyperparathyroidism-jaw tumor (HPT-JT) syndrome is one of the syndromic heritable forms with an autosomal dominant inheritance and incomplete penetrance (5). It has an estimated prevalence of 12% among patients suspected of having heritable forms of PHPT (5). The disease is associated with a higher (20%) prevalence of atypical adenomas or parathyroid cancer (6, 7). In addition to parathyroid tumors, the disease is associated with tumors of the jaw bones, kidney, and uterus (6-9). Heterozygous germline inactivating mutations in CDC73 (cell division cycle 73) cause HPT-JT syndrome (10). CDC73 encodes a ubiquitously expressed putative tumor suppressor protein called parafibromin. Parafibromin is a component of the polymerase associated factor 1 (PAF1) transcriptional-regulatory protein complex that binds to the C-terminal domain of RNA polymerase II and is involved in transcriptional initiation, elongation, and posttranslational events (11, 12). In addition to the germline CDC73 variants predisposing to HPT-JT-associated parathyroid, jaw, kidney, and uterine tumors, somatic CDC73 variants have been reported in several other tumor types including parathyroid, jaw, breast, gastric, and colorectal cancer (13-16). The mechanism for tumor growth in HPT-JT syndrome is presumed to be biallelic inactivation of the CDC73 tumor suppressor gene from a second somatic hit resulting in loss of heterozygosity in accordance with Knudson's “2-hit” hypothesis of tumor development (17, 18). However, this does not explain why certain tissues are more susceptible to the “second hit.” Thus, the biological reason for the tissue-restricted nature of the disease despite the ubiquitous expression of CDC73 remains unclear. There is a paucity of literature on long-term follow-up and the standard of care for patients with the syndrome. The majority of published cohorts describe cross-sectional findings or are limited by small sample size. Optimal evaluation or management of the disease remains uncertain with little evidence to guide clinicians. In this work, we provide our observations during long-term follow-up with one of the largest cohorts of patients with HPT-JT syndrome with the aim of building the evidence base for optimal management of patients with the disease. We describe our experience with parafibromin staining, which is often used in establishing the diagnosis of parathyroid cancer in these patients. Furthermore, we also wanted to understand the molecular changes downstream to CDC73 loss that result in tumors and offer our findings from expression analysis of parathyroid tumors to identify genes regulated directly or indirectly by CDC73.

Patient Selection Written informed consent was obtained from all patients included in this analysis under an institutional review board-approved natural history study of parathyroid disorders (NCT04969926) conducted at the National Institutes of Health (NIH) Clinical Center, Bethesda, Maryland. We identified patients with the clinical diagnosis of HPT-JT syndrome seen under the study. A diagnosis of HPT-JT was established by (1) genetic confirmation of a germline pathogenic variant in CDC73 or (2) clinically affected first-degree relatives of an index case with a confirmed germline CDC73 variant. These clinically affected relatives were presumed to be genetically positive. Genetic testing included sequencing and deletion-duplication analysis for germline mutations in CDC73 in DNA from peripheral leukocytes through commercially available tests (Invitae Corp.). Illustrative Case Report: 6-year-old Male With HPT-JT-related Wilms Tumor A 6-year-old male (DK-1545), a first-degree relative of a patient from previously described HPT-JT kindred (19) with a genetically confirmed germline CDC73 variant (p.L95P) presented to the clinic complaining of a month-long left-sided abdominal pain. Examination was remarkable for a hard mass in the left flank. The patient was also noted to be hypertensive, likely because of the mass effect on the renal vasculature. Abdominal computed tomography revealed a 9.9 × 7 × 10.3-cm large, poorly enhancing, relatively well-circumscribed heterogenous but predominantly solid mass arising from the mid-body of the left kidney abutting the left renal artery which was suspicious for Wilms tumor with no evidence of metastatic disease. The patient underwent left radical nephrectomy with lymph node dissection. Histologically, the mass was most consistent with Wilms tumor penetrating the renal capsule and involving the renal sinus. Lymph nodes were negative for metastases, but the tumor closely approached the surgical margin of resection, supporting a local stage 2 of Wilms tumor. Subsequently, the patient underwent chemotherapy with vincristine and dactinomycin for 19 weeks. A year later, patient was noted to have metastases to the lungs for which he underwent additional chemotherapy followed by radiation therapy. Two years later, patient's disease burden remains stable. Of note, patient remains euparathyroid with no history of PHPT (serum corrected calcium: 9.3 [8.8-10.1] mg/dL; PTH: 12.1 [7.5-53.5] pg/mL). Data Collection Relevant variables were extracted by retrospective chart review using REDCap (Research Electronic Data Capture) electronic data capture tools hosted at National Institute of Diabetes and Digestive and Kidney Diseases (20, 21). A diagnosis of PHPT was established by inappropriate excess of PTH and exclusion of secondary causes of hyperparathyroidism. Histopathological Review of Uterine Specimens Twelve women from 7 kindreds had gynecologic surgery for uterine tumors (7 were symptomatic with menorrhagia; information regarding presentation not available for remaining 5). Only 1 of these patients had the surgery performed at the NIH Clinical Center. Endometrial samples were available from 2 patients (1 outside sample, second from our institute) for independent review. Information regarding histology of uterine specimens on the remaining 10 patients was obtained from prior documentation and confirmed from available pathology reports where available. Immunohistochemistry for Parafibromin Available parathyroid tumor sample from 19 HPT-JT patients (13 with parathyroid adenoma and 6 with parathyroid cancer) were stained for parafibromin alongside parathyroid tumor from a patient with wild-type CDC73 (positive control). Parafibromin expression was evaluated by immunohistochemistry using a mouse monoclonal antibody (Parafibromin, Clone BSB-50, Bio SB; RRID: AB_2938874). Formalin-fixed paraffin-embedded (FFPE) sections were cut at 5 μm, placed in charged slides, and deparaffinized. Antigen retrieval was performed with citrate buffer (pH 6.0) for 30 minutes under steamer (at 95 °C-98 °C) and endogenous peroxidase was blocked with hydrogen peroxide 3% solution for 30 minutes, followed by Dako Dual Endogenous Enzyme Block for 20 minutes. Antibody incubation was performed at room temperature for 45 minutes. Immunohistochemistry was assessed and interpreted as having positive or negative nuclear staining. RNA Sequencing We identified available FFPE parathyroid tumor samples from 35 patients for transcriptome profiling and differential gene expression analysis to understand the cellular pathways and biological processes influenced by CDC73 variants. FFPE sample amplification rate was low, as expected, because of oxidation, chemical modification, and cross-linking by formaldehyde. Six samples were excluded because of bacterial contamination. Of the remaining 29 samples, 24 met quality control criteria (minimum input, 10 ng; % reads, <0.5%) for sequencing on the NovaSeq platform. During data analysis, 3 samples were further excluded because of low mapped reads, leaving 21 samples in total for data analysis (8 HPT-JT-related parathyroid adenoma, 6 HPT-JT-related parathyroid carcinoma, and 7 sporadic parathyroid carcinomas with somatic CDC73 variants excluded by tumor exome sequencing). The raw data were processed using the CCBR RNA-Seq pipeline (https://github.com/CCBR/Pipeliner). Differential gene expression was analyzed with DESeq2 in R studio. The top300 significant differential expressed genes were selected for pathway analysis using Metascape (22).

Clinical Characteristics We identified 68 patients (36 males, 32 females) from 29 kindreds with HPT-JT syndrome (Table 1). Of these, 7 patients were unaffected (2 males, 5 females). There were 40 genetically confirmed patients, whereas 21 (34%) were presumed positive. Median age at last follow-up was 39 (interquartile range [IQR], 29-53) years in the affected patients and 35 (IQR, 25-43) years among the unaffected carriers. The overall median duration of follow-up was 2.95 (IQR, 0.04-10.71) years. The majority of affected patients (40/56) presented with disease-related manifestation between age 10 and 30 years (71%) (Fig. 1A-B). Table 1. | Kindred | Patient | PHPT | Jaw tumors | Uterine tumors | Kidney tumors | |---|---|---|---|---|---| | DK-0500 | DK-0490 | Yes | No | Yes | No | | DK-0500 | Yes | Yes | No | No | | | DK-1101 | DK-1099 | Yes | No | N/A | No | | DK-1100 | No | No | Yes | No | | | DK-1101 | Yes | Yes | N/A | No | | | DK-1105 | Yes | Yes | N/A | No | | | DK-1257 | No | No | Yes | No | | | DK-1545 | No | No | N/A | Yes | | | DK-0525 | DK-0525 | Yes | No | N/A | No | | DK-0528 | No | Yes | N/A | No | | | DK-2028 | DK-2028 | Yes | No | Yes | No | | DK-2123 | DK-2123 | Yes | No | No | No | | DK-2124 | Yes | No | No | No | | | DK-1714 | DK-1714 | Yes | No | N/A | No | | DK-0771 | DK-0771 | Yes | No | N/A | No | | DK-0895 | No | No | N/A | No | | | DK-0896 | No | No | N/A | No | | | DK-2013 | DK-1139 | Yes | No | No | No | | DK-2001 | Yes | No | Yes | Yes | | | DK-2004 | Yes | No | N/A | No | | | DK-2008 | Yes | No | N/A | No | | | DK-2013 | Yes | No | N/A | No | | | DK-2023 | No | No | No | No | | | DK-2038 | Yes | No | N/A | No | | | DK-2206 | DK-2206 | Yes | No | N/A | No | | DK-0364 | DK-0364 | Yes | No | N/A | No | | DK-1369 | DK-1369 | Yes | No | N/A | No | | DK-2007 | DK-2007 | Yes | No | N/A | No | | DK-0609 | DK-0609 | Yes | Yes | N/A | No | | DK-0610 | Yes | No | No | No | | | DK-1421 | DK-1421 | Yes | No | N/A | No | | DK-1626 | DK-0415 | Yes | No | Unknown | No | | DK-0901 | Yes | No | N/A | No | | | DK-1626 | Yes | No | No | No | | | DK-1203 | DK-1203 | Yes | Yes | N/A | No | | DK-2126 | DK-2126 | Yes | No | N/A | No | | DK-1281 | DK-1281 | Yes | No | N/A | No | | DK-1304 | Yes | No | N/A | No | | | DK-1274 | DK-1274 | Yes | No | N/A | No | | DK-0742 | DK-0742 | Yes | No | Yes | No | | DK-1586 | DK-1586 | Yes | No | No | No | | DK-0681 | DK-0681 | Yes | No | N/A | Unknown | | DK-0877 | Yes | No | N/A | No | | | DK-0881 | Yes | No | No | No | | | DK-0107 | DK-0107 | Yes | No | N/A | No | | DK-0111 | Yes | No | Yes | No | | | DK-0118 | Yes | Yes | N/A | No | | | DK-0122 | Yes | No | Yes | No | | | DK-0524 | Yes | No | Yes | No | | | DK-0536 | No | No | No | No | | | DK-0652 | No | No | No | No | | | DK-1226 | Yes | No | Yes | No | | | DK-1285 | Yes | No | N/A | No | | | DK-1294 | Yes | No | N/A | No | | | DK-1503 | Unknown | Unknown | Unknown | Unknown | | | DK-0989 | DK-0989 | Yes | No | Unknown | Unknown | | DK-2016 | DK-0971 | Yes | No | N/A | No | | DK-2016 | Yes | No | N/A | No | | | DK-1011 | DK-1011 | Yes | No | No | No | | DK-0930 | DK-0930 | Yes | No | No | No | | DK-2027 | DK-0793 | Yes | No | No | No | | DK-0827 | No | No | Unknown | No | | | DK-0832 | Yes | No | N/A | No | | | DK-0845 | Yes | No | No | No | | | DK-0980 | Yes | No | Unknown | Unknown | | | DK-2027 | Yes | No | N/A | No | | | DK-1197 | DK-1197 | No | No | Yes | Yes | | DK-1198 | No | No | Yes | Yes | Abbreviation: PHPT, primary hyperparathyroidism. Kindred name is based on the index patient from the family whenever available. If the index was not a National Institute of Diabetes and Digestive and Kidney Diseases patient, or was unknown, then the proband of the family was used to name the kindred. Uterine tumors in males are marked as N/A. Parathyroid Tumors Fifty-five (81%) developed PHPT (Fig. 1A). PHPT was the initial manifestation of the disease in 85% (52/61) of affected patients (Fig. 1C). Median age at PHPT diagnosis was 26 (IQR, 20-35) years. Among those who developed PHPT, 19/55 (35%) were diagnosed because of symptoms, 18/55 (33%) by surveillance of calcium levels because of family history, and 12/55 (22%) were diagnosed on incidental finding of hypercalcemia by routine blood work. Furthermore, 23/55 (42%) developed symptomatic kidney stones, whereas 14/55 (25%) patients developed osteoporosis as indicated by dual-energy x-ray absorptiometry. None of the patients experienced a fragility fracture. Of the patients with PHPT, 36/55 (65%) had parathyroid adenoma, 17/55 (31%) had parathyroid cancer, and 2/55 (4%) had atypical parathyroid tumors on histology (23). Recurrence of PHPT occurred in 20/55 patients; 12/20 (60%) were patients with parathyroid cancer. Among the 55 patients with PHPT, 101 parathyroidectomies were performed: 54/101 index, 45/101 reoperations, and 2/101 autograft-debulking in forearm. Among the neck surgeries with known approach, 38 were bilateral neck explorations, whereas 15 entailed unilateral neck explorations or targeted surgery. This is reflective of the change in our practice in recent years to offer targeted parathyroidectomy to patients with HPT-JT and positive preoperative localization. Of these 15 targeted surgeries, 4 resulted in persistent disease, 2 had recurrences, and 9 attained surgical cure. All but 1 patient with persistent or recurrent disease following targeted surgery had parathyroid carcinoma. Jaw Tumors Jaw tumor was reported in 7/68 (10%) patients with the disease and was the initial manifestation in 3/61 (5%) affected patients (Fig. 1A and C). Median age at presentation of jaw tumors was 24 (IQR, 21-38) years. Of the patients with a jaw tumor, 4/7 patients had surgery to surgically remove the tumor. Tissue samples were available from 2 patients, DK-528 and DK-500, for histological review, which was consistent with ossifying fibromas, 1 from the maxilla (DK-528) and another from the mandible (DK-500). No recurrence of the jaw tumor was noted in any of these patients. Uterine Tumors Among females, 12/32 (38%) females with available follow-up developed uterine tumors, of which 11 had uterine surgeries. Uterine tumors appeared to be the initial manifestation in 5/27 (18%) affected females. Median age at presentation of uterine tumors was 35 (IQR, 23-52) years. Histopathology of the resected uterine tumors (patients frequently had more than 1 pathologic finding) from the 11 females included adenomyoma (n = 5), uterine fibroids (n = 5), adenomyosis (n = 4), cervical polyps (n = 4), adenocarcinoma (n = 1), polypoid adenosarcoma (n = 1), leiomyomata (n = 1), sessile polyps (n = 1), uterine polyps (n = 1), and ovarian fibroids (n = 1). Representative sections of endometrium were available from 2 patients for rereview by a single pathologist (Fig. 2). DK-1100, previously reported by us for successful treatment of menorrhagia by an aromatase inhibitor and subsequent pregnancy (24), underwent several endometrial biopsy/curettages and then hysterectomy for menorrhagia and multiple endometrial polyps. One to 5 representative slides were reviewed from 2 endometrial sampling specimens and all 6 slides of uterus from the patient's hysterectomy (performed at age 35 years) were reviewed. Patient had multiple exophytic polyps on the biopsy/curettage specimens and a single exophytic polyp in the hysterectomy specimen. All these polyps had a similar histologic appearance. They were rounded masses covered by inactive and secretory endometrium composed of glands in spindled stroma that lacked well-developed central cores of vessels. In some areas, the stroma had the appearance of smooth muscle and in other areas was vaguely myomatous. The stromal cells had uniform nuclei and little or no mitotic activity. The glands directly abutted the myomatous stromal component without intervening endometrial stroma. Focally, periglandular stromal condensation was present. Most glands were small and round, but focally, were elongated and phyllodes-like. Both types of glands in the polyps were lined by benign-appearing endometrial epithelium with tubal metaplasia. The hysterectomy specimen additionally showed three similar sessile intraendometrial proliferations. These multiple polyps had focal features suggestive of low-grade adenosarcoma, including phyllodes-like glands and periglandular stromal condensation, but did not have diagnostic features of adenosarcoma such as diffuse architectural changes, stromal atypia, and mitotic activity. Overall, the features were compatible with the diagnosis of atypical adenomyomatous polyps. A second patient, DK-2028, underwent hysterectomy (at age 59 years); only 1 of 23 slides of endomyometrium were available for review from this specimen. The 1 representative section of hysterectomy from this patient showed a subtle microscopic sessile area of small round inactive endometrial glands in myomatous stroma within the endometrium. Kidney Tumors Four patients (6%) with HPT-JT developed solid kidney tumors: 3/4 were females who also had uterine tumors. DK-1545 was the only patient with kidney tumor as the initial disease-related manifestation (1/61, 2%). Median age at presentation of kidney tumor was 45 (IQR, 34-51) years. Three patients had surgery to remove the kidney tumor. On histology, tumors from 2 related patients showed mixed epithelial stromal tumor (MEST), whereas the third patient, a 6-year-old child (DK-1545), had metastatic Wilms tumor (Fig. 3 and 4). We have previously demonstrated biallelic CDC73 loss in HPT-JT-related MEST (25). We now describe the mutational landscape of HPT-JT-related Wilms tumor. Karyotyping of tumor revealed all cells with trisomy 9, which is of unknown importance in Wilms tumor. Next-generation sequencing (TS0500 gene panel) identified the germline CDC73 variant p.L95P but also identified a second CDC73 pathogenic variant in the trans allele, p.M1V (c.1A > G) (variant allele frequency [VAF] = 48%), indicating biallelic loss (26). In addition, the tumor harbored a pathogenic NRAS variant (p.Q61R, VAF = 48%) and a pathogenic TERT variant (c.-124C > T, VAF = 48%). Variants in CDC73 have been reported in 3.3% (5/152) of Wilms tumors and a variety of other kidney tumors (27). Notably, our previously reported patients with MEST (DKs 1197 and 1198) had a CDC73 variant at the same residue (Met1) in their germline (c.3G > T [p.M1I]). Somatic variants at CDC73 Met1 residue have been reported in 2 tumors from metastatic uterine sarcomas in cBioPortal (28). NRAS variants have been reported in <1% (2/413) of Wilms tumor samples in COSMIC. The NRAS p.Q61R seen in the tumor sample is a missense alteration functionally demonstrated to be an activating and oncogenic variant, promoting cell proliferation, invasion, and migration, as well as tumor formation in mice through activation of the mitogen activated protein kinase pathway (29-31). TERT encodes the telomerase reverse transcriptase protein and is frequently amplified in several cancer types (32-34). The TERT promoter c.-124C > T variant seen in the tumor sample occurs before the transcriptional start site within its promoter (35, 36). This alteration has been shown to increase TERT promoter transcriptional activity, telomerase reverse transcriptase protein expression, telomerase activity, and telomere length compared with wild-type TERT (36-38). The variant has also been shown to drive tumor formation in a xenograft model using bladder cancer stem cells, whereas removal of this mutation decreased tumor formation (39). Thus, a synergetic effect of concomitant CDC73, NRAS, and TERT promoter variants cannot be excluded. The fourth patient with kidney tumor, DK-2001 (age 64 years at diagnosis), has the germline CDC73 variant c.164 A > C (p.Y55S) and is currently being conservatively managed for a stable 1.5×1.1-cm tumor. All 3 women with kidney tumors also had a history of uterine tumors. Genetic Findings We found 14 pathogenic CDC73 variants and 5 whole or partial gene deletions among 29 kindreds with HPT-JT syndrome: 5 frameshift indels, 4 non-sense, 4 missense, and 1 splice-site variant (Fig. 5). Variable disease phenotype was noted within the same kindred. For example, in the case of a patient with parathyroid cancer diagnosed at age 16 years (DK-1369), we noted that the variant had a poor penetrance with no clinically evident phenotype in the patient's father, but his grandfather had a history of parathyroid adenoma, diagnosed at age 50 years (Fig. 6A). Similarly, 2 brothers with a large gene deletion in CDC73 had rather contrasting phenotype. Although the proband had metastatic parathyroid carcinoma with no jaw tumors until his death at age 30 (DK-525), his brother (DK-528) had a large right maxillary cementifying fibroma requiring resection without any biochemical evidence of hyperparathyroidism to date at age 50 years (Fig. 6B). Immunohistochemistry for Parafibromin Of the 19 parathyroid tumors (13 with parathyroid adenoma and 6 with parathyroid cancer) available for immunohistochemistry, 5 were from patients with germline missense variants, 7 from patients with frame-shift variants, 6 from patients with whole or partial gene deletions, and 1 from a patient with nonsense variant. Parafibromin staining of parathyroid tumors from patients with HPT-JT showed loss of staining in 7 of 19 parathyroid tumors samples (6/13 adenomas, 1/6 parathyroid cancer) in comparison to positive control (Fig. 7). Of these, 4/7 tumors came from patients with germline frame-shift variants, whereas 3 were from patients with germline missense variants. Overall, 4/7 tumors from patients with frameshift variants and 3/5 from patients with missense variants showed loss of parafibromin staining. Thus, parafibromin staining did not correlate with tumor histology or the patient's genotype. RNA-sequencing Transcriptome data from 21 samples (8 HPT-JT-related parathyroid adenomas, 6 HPT-JT-related parathyroid cancer, and 7 sporadic parathyroid cancer with somatic CDC73 variants excluded by whole exome sequencing) was analyzed to quantify differential gene expression in (1) HPT-JT-related parathyroid carcinoma vs adenoma and (2) HPT-JT-related vs sporadic parathyroid cancer. The differentially expressed genes (DEGs) with more than 2-fold changes were ranked based on false discovery rate. The top 50 most significant DEGs between HPT-JT-related vs sporadic parathyroid cancer included Wnt family member encoding WNT3A, transmembrane serine proteases (TMPRSS4), and tyrosine phosphatase receptor type G (PTPRG) involved in cellular processes including cell growth and differentiation (Fig. 8A). Notably, WNT3A was noted to be downregulated in sporadic parathyroid cancer. However, this downregulation could represent a primary causative or a secondary compensatory process. Pathway analysis showed a significant association of HPT-JT-related parathyroid cancer with growth, transmembrane receptor protein tyrosine kinase signaling pathway, and mesodermal commitment pathway (Fig. 8B). Similarly, the top 50 most significant DEGs between HPT-JT-related parathyroid cancer vs HPT-JT-related parathyroid adenoma included cadherin-related family member FAT1, G-protein subunit alpha (GNAI3), nuclear factor 1B (NFIB), and filamin family (FLNB) (Fig. 8C). Pathway analysis for HPT-JT-related parathyroid cancer vs adenoma showed a significant association of HPT-JT-related parathyroid cancer with epithelial cell differentiation, gland development, and regulation of cellular response to growth factor stimulus (Fig. 8B).

Homozygous Cdc73−/− mutation in mice results in embryonic lethality by embryonic day 6.5 (E6.5), whereas deletion of cdc73 in adult mice leads to severe cachexia and death within 20 days (40). Conventional cdc73+/− mice show reduced survival (Cdc73+/− 80% and cdc73+/+ 90% at 18 months of age) and develop parathyroid tumors from 9 months of age (75% atypical adenomas, 25% adenoma) and uterine tumors (33%) at 18 months of age, but no renal or jaw tumors (41). We present the phenotypic profile of a large cohort of patients with HPT-JT with a high frequency of uterine tumors among females with HPT-JT (38%) and a lower-than-expected preponderance of jaw tumors (10%). We observed a high frequency of uterine tumors (38%) among female patients with HPT-JT presenting during reproductive years at a median age of 35 (IQR, 23-52) years. This frequency is somewhat less than that of 61% and 74% reported in 2 other large series (8, 9). Current histopathological description of the affected endometrium or ovarian tumor is limited by review of tumor from rare reports (7, 9, 42, 43). The majority of uterine lesions reported in this and other series were benign with rare malignant lesions, and even in the absence of slide review included a high proportion of mixed epithelial-mesenchymal lesions described in the pathology reports or clinical notes as adenomyomas, adenomyosis, adenofibromas, multiple adenomyomatous polyps, multiple, recurrent endometrial polyps (uterine polyposis), and a few adenosarcomas (8, 9). Overall, we observed a high frequency of uterine tumors (38%) among female patients with HPT-JT presenting during the reproductive years at a median age of 35 (23-52) years. This frequency is somewhat less than that of 61% and 74% reported in 2 other large series (8, 9). This is similar to the findings in several other series; Bradley et al reported adenomyosis (n = 8), adenofibromas (n = 5), leiomyomas (n = 4), adenosarcomas (n = 2), and endometrial hyperplasia (n = 4) (9), whereas Iacobone et al reported that all their patients with uterine lesions had multiple, recurrent uterine polyps that they termed “uterine polyposis” in all patients (8). Our pathology review of multiple endometrial specimens over a 9-year period from DK-1100 revealed multiple, recurrent atypical adenomyomatous polyps with focal features subdiagnostic of low-grade adenosarcoma. A single case with pathology review in Bradley et al was diagnosed as low-grade adenosarcoma (9). Several other articles have noted similar unusual adenomyomatous polyps in HPT-JT women without detailed morphologic descriptions (24, 42, 44). Given that many of the epithelial-mesenchymal lesions reported in these patients such as adenomyomatous polyps, adenofibromas, and adenosarcomas are very rare in the general population (45) and that multiple, recurrent adenomyomatous polyps with atypical features as described in our series and a small number of cases in the literature are even more rare (46), the frequency of such epithelial-mesenchymal uterine proliferations suggests that these unusual uterine lesions may be a characteristic feature of HPT-JT syndrome. The pathogenesis of adenomyomatous polyps in the general population has not been studied in detail, but the single study in the literature failed to find mutations in exon 2 of MED12, a frequent mutation in uterine leiomyomas (46). Further detailed study of these lesions is necessary to define their precise classification. Our results suggest that patients with HPT-JT with variants at the M1 residue of parafibromin may have a predisposition to solid kidney tumors. Two related female patients with a germline variant at M1 residue and a male child with somatic variant at the M1 residue underwent surgery for aggressive renal tumors with MEST (previously called cystic renal hamartoma or adult cystic nephroma) and Wilms tumor, respectively (25, 47). We hypothesize that variants at this residue alter the translational start site, which potentially leads to either no translation to protein predicting no protein or an altered protein product that may result from either in-frame or out-of-frame translation because of translation starting from an alternative ATG or another noncanonical start codon. Prior literature also describes 4 additional patients with variants at this residue, all of whom had renal tumors (9). Nevertheless, kidney tumors have also been described in patients with CDC73 variants at other residues (48). The 2 females in our series with a variant at M1 residue also had a history of uterine tumors. Our observed frequency of 6% of patients with kidney tumors is lower than 24% as reported by other centers likely because we excluded kidney cysts in our analysis (7). Although somatic CDC73 variants are rare in renal tumors, frequent allelic imbalances of CDC73 are detectable in the different subtypes (12.5% clear cell, 21% papillary, 60% chromophobe renal cell carcinomas, 38% oncocytomas, and 40% Wilms tumors) of sporadic renal tumors (27). Our findings support germline testing of first-degree relatives of a patient with HPT-JT as early as age 6 years (49). HPT-JT was originally described in 1958 in a kindred with hereditary hyperparathyroidism and multiple ossifying jaw fibromas, hence the name (50, 51). Since its initial description, rates of jaw tumors ranging from 3% to 30% have been described (7, 52). Our observed frequency of 11% for jaw tumors is consistent with recent literature that jaw tumors in HPT-JT are not as common as the name might suggest. As seen in our series, these tumors can originate from the maxilla or mandible. CDC73 variants also play a role in the pathogenesis of a subset of sporadic fibro-osseous lesions, ossifying fibromas (53-55). Patients with multiple ossifying fibromas in the jaws are thus recommended to undergo germline testing for CDC73 (56). Our practice is to obtain a panoramic x-ray or a mandibular computed tomography scan at baseline and every 5 years to evaluate for these tumors. Thirty-one percent of our cohort developed parathyroid cancer, which is consistent with reported frequency in published literature (7). We previously reported an association of high-impact variants that predicted significant conformational disruption or loss of expression of parafibromin with parathyroid cancer in comparison to low-impact variants, despite a similar risk of PHPT between the 2 groups (57). Recurrence rate of PHPT was relatively low at 22% in our cohort of patients with parathyroid adenoma, justifying our current approach to perform targeted parathyroidectomy in patients with optimal preoperative localization. However, the median age of our cohort is relatively young at 39 (IQR, 29-53) years for a disease caused by a gene with incomplete penetrance (penetrance 65% at age 50 years) (5). Parafibromin staining was unreliable and not meaningful in our experience, which is consistent with some published literature (58-60). Parafibromin staining can be difficult to perform and interpret (61). The physical properties of the parafibromin antibody and interobserver variability make it challenging to expand its use for diagnostic purposes in the clinics. The majority of the published literature is limited by lack of correlation of the results of parafibromin immunostaining with CDC73 tumor genotype status (60, 62). Parafibromin is predominantly a nuclear protein and is highly expressed in nucleoli (11, 63). It is believed that parafibromin must interact with its targets in the nucleolus to fully execute its tumor suppressor functions (19). It interacts with PAF1 transcription regulatory complex, an RNA polymerase II-associated complex involved in the regulation of genes involved in metabolism and cell-cycle control (11, 12) and induces cell-cycle arrest by repressing cyclin D1 and c-myc, possibly by integrating repressive H3 K9 methylation during transcription (64-67). However, it may also play an oncogenic role in the context of activated SHP-2 and SV40 large T antigen by activating canonical Wnt/B-catenin signal pathway (65, 66, 68–73). Gene expression studies of mice models of the disease show that cdc73 directly regulates genes involved in cell growth and survival, including H19, Igf1, Igf2, Igfbp4, Hmga1, Hmga2, and Hmgcs2 (40). RNA expression analysis of a single HPT-JT-related parathyroid carcinoma, normal parathyroid, and sporadic parathyroid adenoma showed 16 DEGs in the parathyroid cancer sample associated with mitogen activated protein kinase signaling pathways, regulation of actin cytoskeleton, prostate cancer, and apoptosis with upregulation of FGFR1 (74). These findings are consistent with our finding of a significant association of HPT-JT-related parathyroid cancer with transmembrane receptor protein tyrosine kinase signaling pathway. As described, all the pathogenic CDC73 variants seen in our cohort are notably located in the N-terminal domain of CDC73 (Fig. 5), the crystal structure of which has been defined (75). The crystal structure of the N-terminal domain appears to have a GTPase-like fold. However, no GTPase activity for the protein has been described (76). The C-terminal domain is important for PAF1 complex recruitment to genes (77). A nuclear localization signal at residues 136 through 139 and 3 nucleolar localization signal (at residues 76-92, 192-194, and 393-409) have been described in CDC73 (68, 78–80). The strengths of our study include its sample size in the context of a rare disease, longitudinal follow-up, standardized data from a single center, and assessment of correlation of parafibromin staining with genotype status. Nevertheless, our study has some limitations. First, this is a retrospective review and analysis is limited by available data. Second, given the long duration of the study changes in assay and imaging technology over time should be considered. Third, caution should be exercised in interpretation of transcriptome profiling or parafibromin staining because of use of FFPE samples and relatively small sample size. In summary, we describe our experience with HPT-JT syndrome at a single center across several decades and including multiple generations. It is notable that several of the extraparathyroid manifestations of the disease involve mesenchymal proliferations: ossifying fibromas, MESTs, and uterine adenomyomatous polyps. Our findings support germline testing at a young age in first-degree relatives of patients with HPT-JT given the onset of manifestations as early as age 6 years. HPT-JT was associated with a 31% risk of parathyroid carcinoma. However, we do not recommend use of parafibromin immunostaining as a diagnostic tool for parathyroid carcinoma. Variants at M1 residue appear to predispose to genitourinary tumors. At present, there are no therapeutic approaches to compensate for CDC73 inactivation. Future research to identify standards of care, biomarkers to establish the diagnosis of parathyroid cancer, and therapeutics targets are warranted for this rare disease. Acknowledgment The authors are grateful to the patients for their support of our research. The authors thank the trainees of Inter-Institute Endocrine Training Program and the nurses and staff at NIH Clinical Center, NIH for providing clinical care for the study patients. The authors also thank Justin Lack for his guidance with RNA-sequencing analysis. Abbreviations - DEG differentially expressed gene - FFPE formalin-fixed paraffin-embedded - HPT-JT hyperparathyroidism-jaw tumor - IQR interquartile range - MEST mixed epithelial stromal tumor - NIH National Institutes of Health - PAF1 polymerase associated factor 1 - PHPT primary hyperparathyroidism - VAF variant allele frequency Contributor Information Rana Tora, Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. James Welch, Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Jian Sun, NIAID Collaborative Bioinformatics Resource (NCBR), National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Sunita K Agarwal, Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Debra A Bell, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA. Maria Merino, Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. Lee S Weinstein, Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. William F Simonds, Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Smita Jha, Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Funding This work was supported by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases (ZIA DK043006-46) and National Cancer Institute. Disclosures All authors state that they have no conflicts of interest. Data Availability Datasets generated or analyzed during the present study are not publicly available but are available from the corresponding author on reasonable request.

- 1. Melton LJ 3rd. The epidemiology of primary hyperparathyroidism in North America. J Bone Miner Res. 2002;17(suppl 2):N12‐N17. [PubMed] [Google Scholar] - 2. Griebeler ML, Kearns AE, Ryu E, Hathcock MA, Melton LJ 3rd, Wermers RA. Secular trends in the incidence of primary hyperparathyroidism over five decades (1965-2010). Bone. 2015;73:1‐7. [DOI] [PMC free article] [PubMed] [Google Scholar] - 3. Rao SD. Epidemiology of parathyroid disorders. Best Pract Res Clin Endocrinol Metab. 2018;32(6):773‐780. [DOI] [PubMed] [Google Scholar] - 4. Minisola S, Arnold A, Belaya Z, et al. Epidemiology, pathophysiology, and genetics of primary hyperparathyroidism. J Bone Miner Res. 2022;37(11):2315‐2329. [DOI] [PMC free article] [PubMed] [Google Scholar] - 5. van der Tuin K, Tops CMJ, Adank MA, et al. CDC73-related disorders: clinical manifestations and case detection in primary hyperparathyroidism. J Clin Endocrinol Metab. 2017;102(12):4534‐4540. [DOI] [PubMed] [Google Scholar] - 6. Frank-Raue K, Haag C, Schulze E, et al. CDC73-related hereditary hyperparathyroidism: five new mutations and the clinical spectrum. Eur J Endocrinol. 2011;165(3):477‐483. [DOI] [PubMed] [Google Scholar] - 7. Bricaire L, Odou MF, Cardot-Bauters C, et al. Frequent large germline HRPT2 deletions in a French national cohort of patients with primary hyperparathyroidism. J Clin Endocrinol Metab. 2013;98(2):E403‐E408. [DOI] [PubMed] [Google Scholar] - 8. Iacobone M, Masi G, Barzon L, et al. Hyperparathyroidism-jaw tumor syndrome: a report of three large kindred. Langenbecks Arch Surg. 2009;394(5):817‐825. [DOI] [PubMed] [Google Scholar] - 9. Bradley KJ, Hobbs MR, Buley ID, et al. Uterine tumours are a phenotypic manifestation of the hyperparathyroidism-jaw tumor syndrome. J Intern Med. 2005;257:18‐26. [DOI] [PubMed] [Google Scholar] - 10. Carpten JD, Robbins CM, Villablanca A, et al. HRPT2, encoding parafibromin, is mutated in hyperparathyroidism-jaw tumor syndrome. Nat Genet. 2002;32(4):676‐680. [DOI] [PubMed] [Google Scholar] - 11. Rozenblatt-Rosen O, Hughes CM, Nannepaga SJ, et al. The parafibromin tumor suppressor protein is part of a human Paf1 complex. Mol Cell Biol. 2005;25(2):612‐620. [DOI] [PMC free article] [PubMed] [Google Scholar] - 12. Yart A, Gstaiger M, Wirbelauer C, et al. The HRPT2 tumor suppressor gene product parafibromin associates with human PAF1 and RNA polymerase II. Mol Cell Biol. 2005;25(12):5052‐5060. [DOI] [PMC free article] [PubMed] [Google Scholar] - 13. Selvarajan S, Sii LH, Lee A, et al. Parafibromin expression in breast cancer: a novel marker for prognostication? J Clin Pathol. 2008;61(1):64‐67. [DOI] [PubMed] [Google Scholar] - 14. Zheng HC, Takahashi H, Li XH, et al. Downregulated parafibromin expression is a promising marker for pathogenesis, invasion, metastasis and prognosis of gastric carcinomas. Virchows Arch. 2008;452(2):147‐155. [DOI] [PMC free article] [PubMed] [Google Scholar] - 15. Zheng HC, Wei ZL, Xu XY, et al. Parafibromin expression is an independent prognostic factor for colorectal carcinomas. Hum Pathol. 2011;42(8):1089‐1102. [DOI] [PubMed] [Google Scholar] - 16. Rather MI, Swamy S, Gopinath KS, Kumar A. Transcriptional repression of tumor suppressor CDC73, encoding an RNA polymerase II interactor, by Wilms tumor 1 protein (WT1) promotes cell proliferation: implication for cancer therapeutics. J Biol Chem. 2014;289(2):968‐976. [DOI] [PMC free article] [PubMed] [Google Scholar] - 17. Knudson AG J. Mutation and cancer: statistical study of retinoblastoma. Proc Natl Acad Sci U S A. 1971;68(4):820‐823. [DOI] [PMC free article] [PubMed] [Google Scholar] - 18. Bradley KJ, Cavaco BM, Bowl MR, et al. Parafibromin mutations in hereditary hyperparathyroidism syndromes and parathyroid tumours. Clin Endocrinol (Oxf). 2006;64(3):299‐306. [DOI] [PubMed] [Google Scholar] - 19. Panicker LM, Zhang JH, Dagur PK, Gastinger MJ, Simonds WF. Defective nucleolar localization and dominant interfering properties of a parafibromin L95P missense mutant causing the hyperparathyroidism-jaw tumor syndrome. Endocr Relat Cancer. 2010;17(2):513‐524. [DOI] [PMC free article] [PubMed] [Google Scholar] - 20. Harris PA, Taylor R, Minor BL, et al. The REDCap consortium: building an international community of software platform partners. J Biomed Inform. 2019;95:103208. [DOI] [PMC free article] [PubMed] [Google Scholar] - 21. Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)–a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377‐381. [DOI] [PMC free article] [PubMed] [Google Scholar] - 22. Zhou Y, Zhou B, Pache L, et al. Metascape provides a biologist-oriented resource for the analysis of systems-level datasets. Nat Commun. 2019; 10(1):1523. [DOI] [PMC free article] [PubMed] [Google Scholar] - 23. Marini F, Giusti F, Iantomasi T, Brandi ML. Parathyroid tumors: molecular signatures. Int J Mol Sci. 2021;22(20):11206. [DOI] [PMC free article] [PubMed] [Google Scholar] - 24. Wolff EF, Hill MJ, Simonds WF, Segars JH. Aromatase inhibitor treatment of menorrhagia and subsequent pregnancy in a patient with familial hyperparathyroidism-jaw tumor syndrome. Fertil Steril. 2012;98(6):1616‐1619. [DOI] [PMC free article] [PubMed] [Google Scholar] - 25. Vocke CD, Ricketts CJ, Ball MW, et al. CDC73 Germline mutation in a family with mixed epithelial and stromal tumors. Urology. 2019;124:91‐97. [DOI] [PMC free article] [PubMed] [Google Scholar] - 26. Bellido V, Larrañaga I, Guimón M, et al. A novel mutation in a patient with hyperparathyroidism-jaw tumour syndrome. Endocr Pathol. 2016;27(2):142‐146. [DOI] [PubMed] [Google Scholar] - 27. Zhao J, Yart A, Frigerio S, et al. Sporadic human renal tumors display frequent allelic imbalances and novel mutations of the HRPT2 gene. Oncogene. 2007;26(23):3440‐3449. [DOI] [PubMed] [Google Scholar] - 28. Zehir A, Benayed R, Shah RH, et al. Mutational landscape of metastatic cancer revealed from prospective clinical sequencing of 10,000 patients. Nat Med. 2017;23(6):703‐713. [DOI] [PMC free article] [PubMed] [Google Scholar] - 29. Eskandarpour M, Huang F, Reeves KA, Clark E, Hansson J. Oncogenic NRAS has multiple effects on the malignant phenotype of human melanoma cells cultured in vitro. Int J Cancer. 2009;124(1):16‐26. [DOI] [PubMed] [Google Scholar] - 30. Burd CE, Liu W, Huynh MV, et al. Mutation-specific RAS oncogenicity explains NRAS codon 61 selection in melanoma. Cancer Discov. 2014;4(12):1418‐1429. [DOI] [PMC free article] [PubMed] [Google Scholar] - 31. Pylayeva-Gupta Y, Grabocka E, Bar-Sagi D. RAS oncogenes: weaving a tumorigenic web. Nat Rev Cancer. 2011;11(11):761‐774. [DOI] [PMC free article] [PubMed] [Google Scholar] - 32. Cao Y, Bryan TM, Reddel RR. Increased copy number of the TERT and TERC telomerase subunit genes in cancer cells. Cancer Sci. 2008;99(6):1092‐1099. [DOI] [PMC free article] [PubMed] [Google Scholar] - 33. Bodnar AG, Ouellette M, Frolkis M, et al. Extension of life-span by introduction of telomerase into normal human cells. Science. 1998;279(5349):349‐352. [DOI] [PubMed] [Google Scholar] - 34. Greider CW, Blackburn EH. Identification of a specific telomere terminal transferase activity in tetrahymena extracts. Cell. 1985;43(2 Pt 1):405‐413. [DOI] [PubMed] [Google Scholar] - 35. Horn S, Figl A, Rachakonda PS, et al. TERT promoter mutations in familial and sporadic melanoma. Science. 2013;339(6122):959‐961. [DOI] [PubMed] [Google Scholar] - 36. Huang FW, Hodis E, Xu MJ, Kryukov GV, Chin L, Garraway LA. Highly recurrent TERT promoter mutations in human melanoma. Science. 2013;339(6122):957‐959. [DOI] [PMC free article] [PubMed] [Google Scholar] - 37. Kim YJ, Yoo JE, Jeon Y, et al. Suppression of PROX1-mediated TERT expression in hepatitis B viral hepatocellular carcinoma. Int J Cancer. 2018;143(12):3155‐3168. [DOI] [PubMed] [Google Scholar] - 38. Chiba K, Johnson JZ, Vogan JM, Wagner T, Boyle JM, Hockemeyer D. Cancer-associated TERT promoter mutations abrogate telomerase silencing. Elife. 2015;4:e07918. [DOI] [PMC free article] [PubMed] [Google Scholar] - 39. Li C, Wu S, Wang H, et al. The C228T mutation of TERT promoter frequently occurs in bladder cancer stem cells and contributes to tumorigenesis of bladder cancer. Oncotarget. 2015;6(23):19542‐19551. [DOI] [PMC free article] [PubMed] [Google Scholar] - 40. Wang P, Bowl MR, Bender S, et al. Parafibromin, a component of the human PAF complex, regulates growth factors and is required for embryonic development and survival in adult mice. Mol Cell Biol. 2008;28(9):2930‐2940. [DOI] [PMC free article] [PubMed] [Google Scholar] - 41. Walls GV, Stevenson M, Lines KE, et al. Mice deleted for cell division cycle 73 gene develop parathyroid and uterine tumours: model for the hyperparathyroidism-jaw tumour syndrome. Oncogene. 2017;36(28):4025‐4036. [DOI] [PMC free article] [PubMed] [Google Scholar] - 42. Arfi A, Chabbert-Buffet N, Boudy AS, et al. Benign polypoid adenomyomatous endometrium associated with HPT-JT syndrome: a case report. Gynecol Endocrinol. 2020;36(1):30‐32. [DOI] [PubMed] [Google Scholar] - 43. Sirbiladze RL, Uyar D, Geurts JL, Shaker JL. Ovarian granulosa cell tumor in A patient with A pathogenic variant in the CDC73 gene (hyperparathyroidism-jaw tumor syndrome). AACE Clin Case Rep. 2019;5(3):e222-e225. [DOI] [PMC free article] [PubMed] [Google Scholar] - 44. Fujikawa M, Okamura K, Sato K, et al. Familial isolated hyperparathyroidism due to multiple adenomas associated with ossifying jaw fibroma and multiple uterine adenomyomatous polyps. Eur J Endocrinol. 1998;138(5):557‐561. [DOI] [PubMed] [Google Scholar] - 45. Peterson WF, Novak ER. Endometrial polyps. Obstet Gynecol. 1956;8(1):40‐49. [PubMed] [Google Scholar] - 46. Strickland KC, Yuan L, Quade BJ, Nucci MR, Howitt BE. Clinicopathological and immunohistochemical features of uterine adenomyomatous polyps. Hum Pathol. 2019;84:239‐245. [DOI] [PubMed] [Google Scholar] - 47. Teh BT, Farnebo F, Kristoffersson U, et al. Autosomal dominant primary hyperparathyroidism and jaw tumor syndrome associated with renal hamartomas and cystic kidney disease: linkage to 1q21-q32 and loss of the wild type allele in renal hamartomas. J Clin Endocrinol Metab. 1996;81(12):4204‐4211. [DOI] [PubMed] [Google Scholar] - 48. Wijewickrama PSA, Somasundaram NP. Hyperparathyroidism jaw tumor syndrome presenting as recurrent femur fractures in a young woman; a rare presentation of a rare disease. Case Rep Endocrinol. 2020;2020:9298147. [DOI] [PMC free article] [PubMed] [Google Scholar] - 49. Pichardo-Lowden AR, Manni A, Saunders BD, Baker MJ. Familial hyperparathyroidism due to a germline mutation of the CDC73 gene: implications for management and age-appropriate testing of relatives at risk. Endocr Pract. 2011;17(4):602‐609. [DOI] [PubMed] [Google Scholar] - 50. Jackson CE, Norum RA, Boyd SB, et al. Hereditary hyperparathyroidism and multiple ossifying jaw fibromas: a clinically and genetically distinct syndrome. Surgery. 1990;108(6):1006‐1012. [PubMed] [Google Scholar] - 51. Jackson CE. Hereditary hyperparathyroidism associated with recurrent pancreatitis. Ann Intern Med. 1958;49(4):829‐836. [DOI] [PubMed] [Google Scholar] - 52. Iacobone M, Camozzi V, Mian C, et al. Long-Term outcomes of parathyroidectomy in hyperparathyroidism-jaw tumor syndrome: analysis of five families with CDC73 mutations. World J Surg. 2020;44(2):508‐516. [DOI] [PubMed] [Google Scholar] - 53. Costa-Guda J, Pandya C, Strahl M, et al. Parafibromin abnormalities in ossifying fibroma. J Endocr Soc. 2021;5(7):bvab087. [DOI] [PMC free article] [PubMed] [Google Scholar] - 54. Chen Y, Hu DY, Wang TT, et al. CDC73 gene mutations in sporadic ossifying fibroma of the jaws. Diagn Pathol. 2016;11(1):91. [DOI] [PMC free article] [PubMed] [Google Scholar] - 55. Pimenta FJ, Gontijo Silveira LF, Tavares GC, et al. HRPT2 gene alterations in ossifying fibroma of the jaws. Oral Oncol. 2006;42(7):735‐739. [DOI] [PubMed] [Google Scholar] - 56. Wang TT, Zhang R, Wang L, Chen Y, Dong Q, Li TJ. Two cases of multiple ossifying fibromas in the jaws. Diagn Pathol. 2014;9:75. [DOI] [PMC free article] [PubMed] [Google Scholar] - 57. Li Y, Zhang J, Adikaram PR, et al. Genotype of CDC73 germline mutation determines risk of parathyroid cancer. Endocr Relat Cancer. 2020;27(9):483‐494. [DOI] [PMC free article] [PubMed] [Google Scholar] - 58. Quinn CE, Healy J, Lebastchi AH, et al. Modern experience with aggressive parathyroid tumors in a high-volume New England referral center. J Am Coll Surg. 2015;220(6):1054‐1062. [DOI] [PubMed] [Google Scholar] - 59. Mangray S, Delellis R. Parafibromin in the diagnosis of parathyroid carcinoma.pdf. Adv Anatomic Pathol. 2007;14:299‐301. [Google Scholar] - 60. Kruijff S, Sidhu SB, Sywak MS, Gill AJ, Delbridge LW. Negative parafibromin staining predicts malignant behavior in atypical parathyroid adenomas. Ann Surg Oncol. 2014;21(2):426‐433. [DOI] [PubMed] [Google Scholar] - 61. Gill AJ, Lim G, Cheung VKY, et al. Parafibromin-deficient (HPT-JT type, CDC73 mutated) parathyroid tumors demonstrate distinctive morphologic features. Am J Surg Pathol. 2019;43(1):35‐46. [DOI] [PMC free article] [PubMed] [Google Scholar] - 62. Juhlin CC, Nilsson IL, Lagerstedt-Robinson K, et al. Parafibromin immunostainings of parathyroid tumors in clinical routine: a near-decade experience from a tertiary center. Mod Pathol. 2019;32(8):1082‐1094. [DOI] [PubMed] [Google Scholar] - 63. Pazienza V, la Torre A, Baorda F, et al. Identification and functional characterization of three NoLS (nucleolar localisation signals) mutations of the CDC73 gene. PLoS One. 2013;8(12):e82292. [DOI] [PMC free article] [PubMed] [Google Scholar] - 64. Yang YJ, Han JW, Youn HD, Cho EJ. The tumor suppressor, parafibromin, mediates histone H3 K9 methylation for cyclin D1 repression. Nucleic Acids Res. 2010;38(2):382‐390. [DOI] [PMC free article] [PubMed] [Google Scholar] - 65. Lin L, Zhang JH, Panicker LM, Simonds WF. The parafibromin tumor suppressor protein inhibits cell proliferation by repression of the c-myc proto-oncogene. Proc Natl Acad Sci U S A. 2008;105(45):17420‐17425. [DOI] [PMC free article] [PubMed] [Google Scholar] - 66. Zhang C, Kong D, Tan MH, et al. Parafibromin inhibits cancer cell growth and causes G1 phase arrest. Biochem Biophys Res Commun. 2006;350(1):17‐24. [DOI] [PubMed] [Google Scholar] - 67. Farber LJ, Kort EJ, Wang P, Chen J, Teh BT. The tumor suppressor parafibromin is required for posttranscriptional processing of histone mRNA. Mol Carcinog. 2010;49(3):215‐223. [DOI] [PubMed] [Google Scholar] - 68. Lin L, Czapiga M, Nini L, Zhang JH, Simonds WF. Nuclear localization of the parafibromin tumor suppressor protein implicated in the hyperparathyroidism-jaw tumor syndrome enhances its proapoptotic function. Mol Cancer Res. 2007;5(2):183‐193. [DOI] [PubMed] [Google Scholar] - 69. Shen DF, Liu X, Yang XF, et al. The roles of parafibromin expression in ovarian epithelial carcinomas: a marker for differentiation and prognosis and a target for gene therapy. Tumour Biol. 2016;37(3):2909‐2924. [DOI] [PubMed] [Google Scholar] - 70. Takahashi A, Tsutsumi R, Kikuchi I, et al. SHP2 tyrosine phosphatase converts parafibromin/Cdc73 from a tumor suppressor to an oncogenic driver. Mol Cell. 2011;43(1):45‐56. [DOI] [PMC free article] [PubMed] [Google Scholar] - 71. Iwata T, Mizusawa N, Taketani Y, Itakura M, Yoshimoto K. Parafibromin tumor suppressor enhances cell growth in the cells expressing SV40 large T antigen. Oncogene. 2007;26(42):6176‐6183. [DOI] [PubMed] [Google Scholar] - 72. Mosimann C, Hausmann G, Basler K. Parafibromin/Hyrax activates Wnt/Wg target gene transcription by direct association with beta-catenin/Armadillo. Cell. 2006;125(2):327‐341. [DOI] [PubMed] [Google Scholar] - 73. Kikuchi I, Takahashi-Kanemitsu A, Sakiyama N, et al. Dephosphorylated parafibromin is a transcriptional coactivator of the Wnt/Hedgehog/Notch pathways. Nat Commun. 2016;7:12887. [DOI] [PMC free article] [PubMed] [Google Scholar] - 74. Lee JY, Kim SY, Mo EY, et al. Upregulation of FGFR1 expression is associated with parathyroid carcinogenesis in HPT-JT syndrome due to an HRPT2 splicing mutation. Int J Oncol. 2014;45(2):641‐650. [DOI] [PubMed] [Google Scholar] - 75. Sun W, Kuang XL, Liu YP, Tian LF, Yan XX, Xu W. Crystal structure of the N-terminal domain of human CDC73 and its implications for the hyperparathyroidism-jaw tumor (HPT-JT) syndrome. Sci Rep. 2017;7(1):15638. [DOI] [PMC free article] [PubMed] [Google Scholar] - 76. Chen H, Shi N, Gao Y, Li X, Teng M, Niu L. Crystallographic analysis of the conserved C-terminal domain of transcription factor Cdc73 from Saccharomyces cerevisiae reveals a GTPase-like fold. Acta Crystallogr D Biol Crystallogr. 2012; 68(Pt 8):953‐959. [DOI] [PubMed] [Google Scholar] - 77. Amrich CG, Davis CP, Rogal WP, et al. Cdc73 subunit of Paf1 complex contains C-terminal Ras-like domain that promotes association of Paf1 complex with chromatin. J Biol Chem. 2012;287(14):10863‐10875. [DOI] [PMC free article] [PubMed] [Google Scholar] - 78. Hahn MA, Marsh DJ. Nucleolar localization of parafibromin is mediated by three nucleolar localization signals. FEBS Lett. 2007;581(26):5070‐5074. [DOI] [PubMed] [Google Scholar] - 79. Bradley KJ, Bowl MR, Williams SE, et al. Parafibromin is a nuclear protein with a functional monopartite nuclear localization signal. Oncogene. 2007;26(8):1213‐1221. [DOI] [PubMed] [Google Scholar] - 80. Hahn MA, Marsh DJ. Identification of a functional bipartite nuclear localization signal in the tumor suppressor parafibromin. Oncogene. 2005;24(41):6241‐6248. [DOI] [PubMed] [Google Scholar] Associated Data This section collects any data citations, data availability statements, or supplementary materials included in this article. Data Availability Statement Datasets generated or analyzed during the present study are not publicly available but are available from the corresponding author on reasonable request.