Breast cancer biomarkers predict weight loss after gastric bypass surgery

BACKGROUND: Obesity has long been associated with postmenopausal breast cancer risk and more recently with premenopausal breast cancer risk. We previously observed that nipple aspirate fluid (n) levels of prostate specific antigen (PSA) were associated with obesity. Serum (s) levels of adiponectin are lower in women with higher body mass index (BMI) and with breast cancer. We conducted a prospective study of obese women who underwent gastric bypass surgery to determine: 1) change in n- and s-adiponectin and nPSA after surgery and 2) if biomarker change is related to change in BMI. Samples (30-s, 28-n) and BMI were obtained from women 0, 3, 6 and 12 months after surgery. FINDINGS: There was a significant increase after surgery in pre- but not postmenopausal women at all time points in s-adiponectin and at 3 and 6 months in n-adiponectin. Low n-PSA and high s-adiponectin values were highly correlated with decrease in BMI from baseline. CONCLUSIONS: Adiponectin increases locally in the breast and systemically in premenopausal women after gastric bypass. s-adiponectin in pre- and nPSA in postmenopausal women correlated with greater weight loss. This study provides preliminary evidence for biologic markers to predict weight loss after gastric bypass surgery.