Molecular markers of breast cancer cells identified in fine needle aspiration samples from resected sentinel lymph nodes

OBJECTIVE: To analyze a procedure for breast cancer that requires performance of a molecular test before extensive intraoperative examination, fine needle aspiration cytology (FNAC) of surgically removed sentinel lymph nodes (SLNs). STUDY DESIGN: The diagnostic accuracy of extensive histologic examination and immunohistochemistry (IHC) of 101 SLNs from 98 breast carcinoma patients were compared with that of the evaluation of 2 specific mRNA markers by reverse transcriptase polymerase change reaction (mammaglobin and MUC-1). Cell specimens were obtained by FNAC of the SLNs immediately before freezing. RESULTS: Metastases were detected on frozen sections in 19 cases (18.81%). IHC on serial sections confirmed the metastases and showed micrometastases or isolated tumor cells in 24 SLNs (23.76%). Mammaglobin was expressed in 20 FNAC specimens (19.80%). MUC-1 assay was positive in 11 cases only (10.89%). CONCLUSION: This technique allows a complete histologic examination without sacrifice of part of the SLN and at the same time is a valuable diagnostic adjunct to the detection of occult tumor cells. Moreover, it is less expensive and time consuming than extensive IHC.