Clinicopathological features and significance of CD26 expression in papillary thyroid carcinoma

AbstractPurpose This study aimed to evaluate the potential significance of CD26 expression in papillary thyroid cancer (PTC) tissues and to investigate their relationship with classical clinicopathological characteristics and prognosis. Methods Immunohistochemistry (IHC) staining was used to explore the expression pattern of CD26 in PTC tissues and corresponding adjacent tissues in 86 patients. In addition, we searched GEPIA database to estimate the expression difference of CD26 mRNA in thyroid cancer and normal thyroid tissues, and download the expression bar graph of mRNA and Kaplan Meier curve of CD26 in PTC compared to normal thyroid tissues. Results We found that 89.53% (77/86) of PTC overexpressed CD26, on the contrary, we observed that CD26 was not expressed in normal thyroid tissues adjacent to the tumor. The expression of CD26 was strongly associated with lymph node metastasis (ꭓ2 = 7.59,P = 0.006), tumor size (ꭓ2 = 7.59,P = 0.006) and patients' age (ꭓ2 = 3.95,P = 0.047), but there had no association between CD26 expression and patients' gender, capsular invasion (P > 0.05). Moreover, CD26 mRNA level was extremely low in normal thyroid tissues and significantly increased in thyroid cancer tissues(P < 0.01). Survival analysis presented that the patients with higher CD26 mRNA expression owned lower disease-free survival (DFS) and higher recurrence risk (HR = 1.8,P = 0.048). Conclusion Our data demonstrated that CD26 might be promising biomarkers and therapeutic target for PTC.