Abstract 3255: Circulating adipose stromal cells (CASCs) as a potential biomarker of response to weight loss interventions in obese women at high risk for breast cancer

Abstract

Abstract Background Obesity is a modifiable risk factor for breast cancer in the United States. White adipose tissue is increased in obese (BMI ≥ 30 kg/m2) women, releasing estrogens and pro-inflammatory cytokines. Adipose stromal cells play a key role in releasing estrogens, while circulating adipose stromal cells (CASCs, characterized as CD34+CD31-CD45-) home to tumor sites and promote angiogenesis and vascularization. CASCs have been correlated with BMI in both cancer and non-cancer patients. However, BMI alone as a marker of adiposity has its limitations. We examined whether CASCs correlate with additional measures of adiposity in women who are at high risk for development of breast cancer. Methods Women at high risk for development of breast cancer but without prior breast cancer were recruited for random periareolar fine needle aspiration (RPFNA), DEXA body composition, anthropomorphic assessment, and non-fasting venous blood collection. Mononuclear cells were isolated and the frequency of CD34brightCD31-CD45- cells was assessed by flow cytometry. Results CASC frequency ranged from 0 to 0.018% (median 0.001%) for 13 non-obese and 20 obese women. There was no association between CASC frequency and BMI (range 19 - 46 kg/m2), either as a linear correlation or when dichotomized at a BMI of 30 kg/m2. However, there were tendencies for greater CASC frequencies in pre-menopausal women, women with greater waist circumference (p<0.050), and women with visceral fat mass greater than 50%. With limited numbers, there was no apparent association of CASC frequency with cytology or proliferation (Ki-67) of benign breast epithelial cells acquired by RPFNA. Conclusions This is the first study to investigate CASC frequency in a cohort of women at high-risk for development of breast cancer. Our results to date do not show an association between CASC frequency and obesity (BMI). However, associations with other indices of visceral fat suggest that evaluation of circulating adipose stromal cells could have value as a biomarker of response in clinical trials of obese breast cancer survivors and high risk women undergoing weight loss (especially fat mass) interventions. Citation Format: Hailey Baker, Amy L. Kreutzjans, Jennifer L. Nydegger, Teresa L. Phillips, Richard C. Hasting, Dan A. Dixon, Bruce F. Kimler, Carol J. Fabian. Circulating adipose stromal cells (CASCs) as a potential biomarker of response to weight loss interventions in obese women at high risk for breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3255. doi:10.1158/1538-7445.AM2017-3255