ERBB2 status and benefit from adjuvant tamoxifen in ER alpha-positive postmenopausal breast carcinoma

We examined the relation between ERBB2 gene expression (as determined by a real-time quantitative RT-PCR assay) and the response to adjuvant tamoxifen therapy in a well-defined cohort of 125 ER alpha -positive postmenopausal patients with breast cancer. Although ERBB2 overexpression was associated w ith shorter relapse-free survival in univariate analysis (P = 0.00029), ERB B2 did not persist as an independent prognostic factor in multivariate anal ysis. Nevertheless, when we analyzed the ERBB2 mRNA level as a continuous v ariable, the higher the ERBB2RNA level, the poorer the outcome (P = 0.00036 ). The results point to the need for a quantitative ERBB2 expression assay for use in future studies of ERBB2-based clinical management of breast canc er. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.