c-erbB2 overexpression decreases the benefit of adjuvant tamoxifen in early-stage breast cancer without axillary lymph node metastases

Purpose: We studied retrospectively the interaction between c-erbB2 overexpression and adjuvant tamoxi-fen in node-negative breast cancer patients enrolled in the Gruppo Universitario Napoletano 1 (GUN-1) trial. Patients and Methods: c-erbB2, evaluated by immu-nohistochemistry in 145 of 173 patients randomly as-signed to 2-year adjuvant tamoxifen or no further ther-apy, was considered overexpressed if greater than 10% of the cells showed specific membrane staining. The role of each prognostic variable and their independent effect were studied using the Cox model. Disease-free (DFS) and overall (OAS) survival curves were estimated by the Kaplan-Meier method. Results: As of November 30, 1994, the median fol-low-up period was 12 years. c-erbB2 was overexpresse