Gene Expression in Blood Samples from High-Risk Postmenopausal Women Who Received Treatment on Breast Cancer Prevention Clinical Trials NSABP-P-1 or NSABP-P-2

Summary

Objectives

PRIMARY OBJECTIVES:
I. To identify genes, as measured by single nucleotide polymorphisms (SNPs), that are associated with breast events, which are defined as the occurrence of invasive breast cancer or ductal carcinoma in situ (DCIS), in Caucasian women at high risk of developing breast cancer who have received a selective estrogen receptor modulator (SERM) (tamoxifen or raloxifene) on the NSABP P-1 or NSABP P-2 trials.
II. To determine the impact of cytochrome P450 family 2, subfamily D, polypeptide 6 (CYP2D6) metabolizer status, which includes genotype and status of concurrent use of CYP2D6 inhibitors, on breast cancer events in participants receiving either tamoxifen or raloxifene.

SECONDARY OBJECTIVES:
I. To explore whether multiple SNPs within a region are independently associated with a breast event.
II. To explore whether there are interactions among SNPs that increase the risk for a breast event.
III. To explore whether there is interaction of any SNPs identified in the primary objective with randomized treatment, in terms of the risk for a breast event.

TERTIARY OBJECTIVES:
I. To identify rare variants that might affect estrogen-dependent expression of these genes and/or their relationship to breast cancer 1, early onset (BRCA1) expression.

OUTLINE:
DNA extracted from previously collected blood samples is analyzed in a genome-wide association study and compared with 2 control samples from patients who did not experience a breast event. DNA samples are used to identify and analyze SNPs.