OBJECTIVES:
* To prepare, separate into components, and store the blood specimens at the NSABP Serum Bank at Baylor College of Medicine Breast Center for future DNA, RNA, and plasma analysis, and to analyze specific proinflammatory cytokines, genetic polymorphisms, and RNA expression arrays in collaborating laboratories at University of California, Los Angeles (UCLA).
* To examine the association between markers of inflammation and symptoms of fatigue among patients with and without exposure to metformin hydrochloride.
* To examine the relationship between single nucleotide polymorphism (SNPs) in the promoter regions of IL-1 and IL-6 and symptoms of fatigue with and without exposure to metformin hydrochloride.
* To examine RNA expression profiles in relationship to fatigue and compare the pattern of expression in patients with and without exposure to metformin hydrochloride.
* To determine the biological and behavioral predictors of fatigue in breast cancer patients in the five years post-randomization.
* To determine whether metformin is associated with reductions in inflammatory markers and corresponding decreases in fatigue. (Exploratory)
OUTLINE: This is a multicenter study.
Patients' serum and plasma, collected at baseline and at 6, 12, and 24 months after NCIC CTG MA.32 randomization, are analyzed for inflammatory markers, DNA polymorphisms, and RNA expression arrays by ELISA, TaqMan PCR, and RT-PCR.
Patients complete the Fatigue Symptom Inventory (symptoms associated with fatigue, sleep disturbance, depression, and endocrine therapy) at baseline and periodically during study.
