HER2/neu status in primary breast cancer and in metastatic site as detected using FNA.
e11502 Background: As for hormonal receptor (ER, PgR), also human epidermal growth factor receptor-2 (HER-2) expression in breast cancer primitive tumor (PT) could be different from that of metastatic site (MS). These differences arise some questions about clinically useful information given and accuracy of methods to detect biological features. Fine Needle Aspiration (FNA) of metastatic sites could be an available tool to characterize biologic pattern of lesions, using immunocytochemical and/or molecular assay. The aim of the study is to compare prognostic and predictive factors obtained from PT and corresponding MS. Methods: Thirty-eight consecutive metastatic breast cancer patients underwent FNA on metastatic sites in order to re-evaluate receptor status, proliferative activity and HER-2/Neu amplification. In MS the material was achieved using FNA with a 21-23 G needle and obtaining monolayer and the corresponding cito-inclusion. MS were localized in liver (21), lung (8) and distant lymph-nodes (9). ERs, PgRs and Ki-67 were detected in both PT and MS, in 38 cases by immunochemistry, whereas HER-2/Neu amplification was detected on citoinclusion in 35 evaluable cases by FISH. Results: ERs, PgRs and Ki-67 were detected in both PT and in MS, in 36, 34, 25 out of 38 cases respectively, showing a significant loss of hormonal receptors and a decreased proliferative activity in MS versus PT (t-test p: 0.0195, <0.0001 and 0.0120 respectively). Regarding to HER-2/Neu amplification, 28 out of 35 evaluable cases were not amplified while 6 were amplified both in PT and in MS (Pearson Test: r=0.9 p: <0.0001). Another case, HER/Neu amplified in TP, after therapy with trastuzumab resulted not amplified in MS. Conclusions: According to other authors, our data demonstrated that the lost of HER/Neu amplification in MS is a possible event and that FNA samples of MS are available for HER/Neu detection.