Trial Information

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

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.