Evaluation of the Co-Expression of the Cancer Stem Cell Marker ALDH1 and of HER2 as a Predictor of Adjuvant Trastuzumab Response in Breast Cancers of Women in NSABP B31

Brief Summary

Detailed Description

OBJECTIVES: Primary * To determine if stem cellness identifies a poor prognostic subgroup of women with early-stage breast cancer who have been uniformly treated with either adjuvant doxorubicin hydrochloride \& cyclophosphamide followed by paclitaxel (the "control arm" of B31), or the same chemotherapy plus trastuzumab. Secondary * To conduct exploratory analyses to assess, to the extent possible, if co-localization of stem cellness, as determined by ALDH1 positivity, and HER2 identifies a group of patients previously considered to have HER2-negative cancers (using classical definitions) who benefit from adjuvant trastuzumab. OUTLINE: Archived breast cancer stem cells samples and terminally differentiated cells from tissue samples are analyzed for HER2 and ALDH1 expression by dual-staining quantitative immunofluorescence using Automated Quantitative Analysis (AQUA) , IHC, and fluorescence in situ hybridization (FISH).

Primary Outcomes

Secondary Outcomes

• HER2 expression in cells with stem cell-like properties as a determinant of aggressiveness and response to trastuzumab in the adjuvant setting(approximately 4 years)