HER-2 Status May Change in Recurrent Breast Cancer.

Abstract

Introduction:The human epidermal growth factor receptor (HER-2) is a cell membrane surface-bound receptor tyrosine kinase which has been associated with increased breast cancer recurrence and a worse prognosis. Its presence also determines which patients are candidates for targeted therapy with trastuzumab. The purpose of this retrospective study was to determine the percentage of HER-2 status change in recurrent breast cancer.Methods:In this study, we retrospectively reviewed the charts of 2,652 patients diagnosed with breast cancer in our institutution between 2003 and 2009. Forty-four patients with recurrent breast cancer and available HER-2 status at the time of diagnosis and at recurrence were identified. HER-2 status was assessed by immunohistochemistry (IHC) and/or fluorescence in situ hybridization (FISH). When both methods were available, we used FISH as our reference.Results:A change in HER-2 status at recurrence was observed in six patients (13.6%). One patient (2.3%) changed from negative to positive. Five patients (11.3%) had a change from positive to negative. These five patients represented 50% of the patients with positive HER-2 at the time of initial diagnosis. HER-2 status remained unchanged in thirty-eight patients (86.4%).Conclusion:A change in HER-2 status can be noted at the time of recurrence. The exact mechanism is not yet well understood, and further studies are needed to identify it. Our data support the fact that patients with recurrent breast cancer should have their HER-2 status re-evaluated, since this affects therapeutic options. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5109.

Testing for HER2 in Breast Cancer: Current Pathology Challenges Faced in Canada

“…Concordance between the her2 status of primary tumour tissue and metastases has been investigated in several small studies. In retrospective studies in which her2 status was compared between primary and metastatic tumour samples, discordance rates between 3.0% and 13.6% have been reported, although these examples are not exhaustive 37,[39][40][41][42][43][44][45] . Changes in her2 status from the primary to the metastatic setting-both from her2-positive to her2-negative and from her2-negative to her2-positive-have been reported.…”