Abundance and distribution of polychlorinated biphenyls (PCBs) in breast tissue.

Abstract

Abstract Abstract #5039 Background: Breast cancer is a complex disease whose causative factors remain ambiguous and poorly defined. Many environmental chemicals accumulate in human tissues and may contribute to breast cancer risk. Polychlorinated biphenyls (PCBs), which constitute a class of chlorinated compounds that are ubiquitous in the environment, are believed to be associated with adverse health effects. Because the rising incidence of breast cancer may result from exposure to increasing levels of exogenous chemicals, there is keen interest in determining relationships between exposure to environmental chemicals and breast cancer risk.
 Material and Methods: Frozen sections of breast tissue were collected from each quadrant and the central region of the breast from 47 patients enrolled in the Clinical Breast Care Project at Walter Reed Army Medical Center. Pathological diagnoses ranged from disease free prophylactic mastectomy to metastatic breast cancer. From a portion of each sample, 98 PCB congeners were assayed by pressurized liquid extraction followed by high resolution gas chromatography.
 Results: PCBs were abundant in breast tissues. Only one congener was not observed in any patient and four (153, 138+163, 180, 206) were seen in all patients in at least one quadrant. Mean total PCB concentration in 202 breast quadrants was 602 ng/g lipid (range 0-4030), while for individual congeners, PCB 153 had an average level of 107 ng/g lipid (range 8-773 ng/g). Total PCB concentration (P<<0.001) and presence of 26 congeners (P<0.05) were highly correlated with patient age, particularly in the UIQ and LOQ, but not in the central region, suggesting that chemicals may accumulate at different rates in different regions of the breast. Similarly, no significant differences were observed for PCB concentrations among the four traditional quadrants, but 23 PCBs were present at significantly lower levels (P<0.05) in the central region. When examining PCB levels by disease status, seven individual congeners and median overall levels were significantly higher (P<0.05) in patients with invasive cancer compared to disease free patients.
 Discussion: Population monitoring is beginning to assess exposures of the general public to environmental chemicals to evaluate long-term health effects. This study showed that many PCB residues are present in human breast tissue, these chemicals are not distributed evenly, and several are correlated with age and presence of invasive disease. Improved understanding of the true carcinogenic potential of environmental chemicals may be useful in efforts to reduce individual risk for breast cancer. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5039.