Abstract P1-02-04: Adipocyte fatty acid binding protein levels predict risk of obesity associated breast cancer

Abstract

Abstract Background: Breast cancer risk has been linked to obesity, especially in postmenopausal women. Adipocyte fatty acid binding protein (A-FABP) is found in adipose tissue, and preliminary evidence suggests that its expression in serum is associated with obesity and breast cancer risk. Surgery for morbid obesity appears effective in decreasing morbidity and/or mortality from a variety diseases of adulthood, including cancer. We evaluated the association of A-FABP expression with 1) body mass index (BMI), 2) breast cancer and 3) change in BMI after obesity surgery. Hypothesis: Increased A-FABP expression is associated with 1) BMI level, 2) breast cancer, and 3) change in BMI after obesity surgery. Methods: Serum was collected under an institutional review board approved protocol from two cohorts of obese women: 1) those with or without breast cancer, and 2) those undergoing surgery for morbid obesity. In the first cohort, samples were collected from 101 women prior to surgery to diagnose and treat a concerning breast lesion. In the second, samples were collected from 82 healthy obese women at baseline, and whenever possible, at 3, 6, and 12 months after obesity surgery. A-FABP levels in serum were measured using human A-FABP4 ELISA kits. The student's t-test was used to compare A-FABP levels in the two groups. Linear mixed effect models were used to examine the relationship between A-FABP and BMI or change of BMI over time, controlling for age, menopause status and history of breast cancer. Results: A-FABP levels were significantly higher in women with cancer than healthy controls among obese women (p=0.039), but not among non-obese women (p > 0.05). A-FABP levels were higher in obese than non-obese women without (p=0.038) and with breast cancer (p<0.001). Among healthy obese controls, A-FABP was associated with BMI at baseline (p=0.016) and its change over time after surgery (p=0.005). The association of A-FABP with BMI was significant for women of normal breast cancer risk regardless of their menopause status (p=0.012 for pre-menopause and p<0.001 for post-menopause), but not for those with a family history of breast cancer (p>0.05). A-FABP was also more predictive of change in BMI in postmenopausal normal risk women (p<0.001) than in other groups (p>0.05). Impact: Circulating levels of A-FABP are associated with cancer in obese women, with baseline BMI in healthy women and with change in BMI in normal risk women undergoing surgery for morbid obesity. These findings all point to a clinically important mechanistic role for A-FABP in obesity influenced breast cancer. They also suggest that downregulation of A-FABP may be involved in the decreased risk of cancer, including breast cancer, that has been observed in follow-up after obesity surgery. Citation Format: Sauter E, Hao J, Yan X, Kong M, Li B. Adipocyte fatty acid binding protein levels predict risk of obesity associated breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-04.