Discordance rate of HER2 status in primary breast carcinomas versus synchronous axillary lymph node metastases: a multicenter retrospective investigation

Abstract

Simultaneous determination of HER2 in BC and corresponding metastatic lymph nodes is not mandatory, but may strongly influence the therapeutic management. It was demonstrated that loss of HER2 amplification results in worse post-relapse survival and overall survival in BC patients and, on the other hand, a gain in HER2 expression in metastatic lymph nodes of BC may allow the possibility of a targeted treatment. Thus, our opinion is that significant prognostic information may be obtained by simultaneous assessment of HER2 status in both primary and synchronous metastatic BC.