Quantitative Protein and Gene Expression Biomarkers of Tamoxifen and Letrozole Recurrence in the NCIC CTG MA.17 Cohort

Brief Summary

Detailed Description

OBJECTIVES: * Assess the prognostic utility of the MGH 2-gene and the GHI 21-gene expression signatures in postmenopausal women with primary breast cancer treated with tamoxifen followed by either placebo or letrozole on clinical trial CAN-NCIC-MA17. * Assess the ability of the MGH 2-gene and the GHI 21-gene expression signatures to predict responsiveness to letrozole. * Compare the prognostic utility of quantitative immunofluorescence vs standard immunohistochemistry of estrogen receptor, progesterone receptor, HER-2, tumor aromatase, cyclooxygenase-2, GATA-3, and NAT-1 in these patients. * Assess the ability of quantitative immunofluorescence and standard immunohistochemistry of these proteins to predict responsiveness to letrozole in these patients. * Use gene discovery from formalin-fixed, paraffin-embedded tumor specimens to identify novel gene expression profiles that may predict outcome and responsiveness to letrozole in these patients. OUTLINE: This is a controlled study. Formalin-fixed, paraffin-embedded breast tumor tissue samples are analyzed for MGH 2-gene and GHI 21-gene expression signatures using real-time quantitative polymerase chain reaction. Immunohistochemistry and immunofluorescence are used for analysis of estrogen receptor, progesterone receptor, HER-1 and -2, aromatase, GATA-3, NAT-1, and cyclooxygenase-2. Microarray hybridization is used to identify novel gene expression signatures. PROJECTED ACCRUAL: A total of 957 specimens will be accrued for this study.

Primary Outcomes