(A) Experimental schematic showing the collection of breast adipose tissue conditioned medium (CM) from women with BMI < 25 and with BMI ≥ 25. (B) MCF-10A cells were treated with CM for 24 hours. DNA damage assessed by IF (number of γH2AX foci/100 cells) is shown correlated with BMI in BRCA1+/− (n = 36 CM cases) and (C) BRCA2+/− (n = 13 CM cases) MCF-10A cells. Blue dotted line represents amount of DNA damage induced by control CM (medium not conditioned by adipose explants). Spearman’s rank correlation coefficient (ρ) and associated P value are shown along with 95% confidence intervals. (D) DNA damage in BRCA1+/− and BRCA2+/− MCF-10A cells and in (E) primary BRCA1+/− breast epithelial cells treated with leptin (400 ng/μl) for 24 hours. (F) DNA damage in BRCA1+/− MCF-10A cells after 24-hour treatment with CM derived from a woman with BMI < 25 (“BMI < 25 CM”), with obesity (“Ob CM”), or with Ob CM in the presence of a leptin-neutralizing antibody (“Lep Ab”). (G) DNA damage in BRCA1+/− and BRCA2+/− MCF-10A cells and in (H) primary BRCA2+/− breast epithelial cells treated with insulin (100 nM) for 24 hours. (I) DNA damage in BRCA1+/− MCF-10A cells after 24-hour treatment with BMI < 25 CM, Ob CM, or Ob CM in the presence of PI3K inhibitor BKM120 (1 μM). Student’s t test was used to determine significant differences in (D) to (I). All experiments in MCF-10A cells were conducted a minimum of two times, with representative results from one experiment shown. Data in primary cells were generated from cells treated in triplicate. Data are presented as means ± SD. *P < 0.05, **P < 0.01, ***P < 0.001.