Polychlorinated biphenyls and breast cancer risk by combined estrogen and progesterone receptor status

Studies have suggested that breast cancer risk factor profiles may vary according to joint estrogen receptor (ER) and progesterone receptor (PR) tumor status. Most of the published literature to date which has investigated the association between exposure to organochlorine compounds and breast cancer has reported null or weak associations. If, indeed, the classification by hormonal receptor status identifies different forms of breast cancer, then assessing the risk of exposure to polychlorinated biphenyls (PCBs) on breast cancer as one disease or stratifying based on ER or PR status alone may obscure the association between PCBs and breast cancer. A hospital-based case-control study of 266 cases and 347 benign breast disease controls was conducted to examine the association of blood serum and adipose tissue concentrations of PCBs with breast cancer by joint ER/PR status. Total PCBs were measured in blood serum, and the following PCB congeners were measured in breast adipose tissue: 74, 118, 138, 153, 156, 170, 180, 183, 187. We did not detect any clear relationship or change in breast cancer risk based on joint ER/PR tumor status for body burden of PCBs, whether measured in blood serum or breast adipose tissue, by total PCBs or for specific congeners. These results confirm previous findings in the literature of no positive association between environmental exposure to PCBs and risk of breast cancer.