Organochlorine pesticide residues in human breast tissue and their relationships with clinical and pathological characteristics of breast cancer

Agricultural pesticides are abundant environmental contaminants worldwide, prompting interest in studying their possible detrimental health effects. We examined organochlorine residues by quadrant (n = 245) in breast adipose tissues from 51 women with various stages of breast health to determine patterns of bioaccumulation within the breast and to assess relationships with patient clinical characteristics. Three organochlorine residues—2,2‐bis(p‐chlorophenyl)‐1,1‐dichloroethylene (p,p′‐DDE), hexachlorobenzene (HCB), and mirex—assayed by high resolution gas chromatography were abundant in breast tissue. p,p′‐DDE (745 ± 1054 ng/g lipid) was the most prevalent residue, comprising 97.5% of the total chemical burden. Mean levels of p,p′‐DDE and HCB were significantly correlated (P < .001) with patient age at mastectomy, and levels of p,p′‐DDE were correlated (P < .05) with BMI. Pesticide concentrations did not differ significantly by breast quadrant and were not different in the quadrant(s) where the primary tumor was located compared to other cancer‐free quadrants. In invasive cancer patients, organochlorine levels differed significantly based on clinical characteristics of the primary carcinoma, including stage, grade, ER status, and HER2 status, indicating that body burden of organochlorines may influence the development of specific subtypes of breast cancer. Potentially carcinogenic organochlorines were present at high levels within the human breast warranting further research to determine the impact of organochlorines in the etiology of breast cancer.