Abstract 4363: A-FABP and estrogens are independently involved in the development of breast cancer

Abstract

Abstract Background: We previously reported that postmenopausal obese women exhibit increased levels of circulating adipocyte fatty acid binding protein (A-FABP), which is associated with breast cancer (BC) development. In postmenopause, increased estrogen levels are associated with increased BC risk. Hypothesis: Estrogens (estrone: E1, estradiol: E2 and estriol: E3) are associated with A-FABP in the setting of obesity and obesity-related BC development. Methods: Immunoassays for E1, E2, E3, and A-FABP were performed using serum samples from women with and without BC. Results: Statistical analysis was conducted using the Mann-Whitney test and multiple linear regression models. Considering all subjects, E1 and E2 but not E3 levels were significantly higher in pre- than in postmenopause among both non-obese and obese individuals (p<0001). E3 (p<0.01) and E1 (p<0.05) levels were higher in non-obese than in obese women. A-FABP levels were significantly higher in obese postmenopausal women with and without BC, but not in premenopausal women, regardless of BC status. When stratified by BC status, E2 levels were significantly higher, while E1 and E3 levels were significantly lower in postmenopausal healthy obese than non-obese women. These body mass index (BMI) based differences were not observed among women with BC. E3 levels were higher in obese pre (p=0.003) and postmenopausal (p=0.001) women with BC than those without. A-FABP levels were significantly higher in postmenopausal obese healthy women and women with BC. A-FABP was not highly associated with E1, E2 or E3. Impact: 1) A-FABP expression is increased in postmenopausal obese women with and without BC; 2) E1 and E2 expression is higher in pre- than postmenopausal women, regardless of BMI; 3) E1 and E3 levels are higher in lean than obese individuals, regardless of menopausal status; 4) the influence of obesity on E1, E2 and E3 expression in postmenopause is lost in women with BC, 5) E3 is increased in obese vs. non-obese women with BC, and 6) A-FABP and estrogens are independently involved in the development of BC. Citation Format: Bing Li, Jiaqing Hao, Xiaofang Yan, Maiying Kong, Edward Sauter. A-FABP and estrogens are independently involved in the development of breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4363.