Determination of the Androgen Receptor Status of Disseminated Tumor Cells in Primary Breast Cancer Patients

AbstractPurpose Androgen receptor (AR) can serve as a new therapy target since it was shown to play a proliferative role in several BC subtypes. Moreover AR-positivity has been suggested to reflect the metastatic potential of tumor cells in some of BC subtypes. The aim of this study was to determine the AR-expression on disseminated tumor cells (DTCs) as a surrogate marker of minimal residual disease (MRD) and potential precursor of metastasis in early BC. Methods Bone marrow (BM) aspirates from 62 DTC-positive early BC patients were included into this study and analysed by immunofluorescence triple staining for the presence of AR-positive DTCs. CK-positive, CD45-negative cells that contained an intact nucleus (DAPI-positive) were identified as DTCs. The AR expression of the PT was assessed by immunohistochemistry on formalin-fixed, paraffin-embedded (FFPE) tumor sections from core biopsies and surgical specimens. Results AR-status of DTCs could be determined in 21 patients and 9 of those (43%) had AR-positive DTCs. No correlation could be found between positive AR-status of DTC and any of the clinicopathological factors. AR expression of DTC and corresponding PT showed a concordance rate of 33%. No significant correlation could be observed between the AR status of the PT and any of the established prognostic factors for BC. Conclusion AR-positive DTCs can be detected in BM of early BC patients with a marked discordance of the AR status between DTCs and corresponding PTs. The clinical significance of these findings needs further investigation.