p95HER2 expression in HER2‐positive breast cancer with primary resistance

Abstract

Abstractp95HER2 isoform is a truncated form of HER2 that retains the C terminal domain but lacks an N terminal trastuzumab binding site. From 2014 to 2016, we assessed the expression of p95HER2 expression in 59 HER2‐positive breast cancer patients from FUSCC. The median follow‐up was 54 months. In our study, 19 patients (32.2%) were p95HER2 positive. p95HER2‐positive expression rate is higher in premenopausal patients than in postmenopausal patients (68.4% vs. 31.6%, P = .026). p95HER2 positive was found more in premenopausal patients and was associated with worse DFS (hazard ratio, 2.21; 95% CI, 1.06–4.61; P = .034), indicating that p95HER2 expression tends to be a more aggressive isoform type of HER2‐positive breast cancer.