Luminal B breast cancer and prognostic value of HER2 overexpression: Retrospective analysis of a single-institution series.

Abstract e11120 Background: Luminal B is a heterogeneous estrogen-receptor positive breast cancer subtype, with a higher proliferation rate and a poorer prognosis than luminal A. Overexpression of HER2 oncogene identifies tumors with a different clinical behavior. This study evaluates the prognostic role of HER2 expression in luminal B tumors. We retrospectively analyzed the clinicopathologic characteristics of 2005 early breast cancer pts (I-IIIB clinical stages) diagnosed between 1997 and 2007 at our institution. 47% of pts fulfill luminal B-subtype criteria: ki67≥14%, PR