Environmental Organochlorine Exposure as a Potential Etiologic Factor in Breast Cancer

Abstract

Known risk factors for breast cancer do not account for a significant proportion of the overall incidence. Reproductive factors and endogenous hormones are thought to be responsible for a large component of risk. An environmental contribution has been sought in the past to explain the international trends in breast cancer rates and changes in risk among migrating populations. Recently, environmental research has turned to investigation of exogenous chemical exposures, including environmental contamination, as potential risk factors that may arise from the hormonal activity or from the carcinogenicity of many of these chemicals. Several reports since 1991 suggest that organochlorines may be a risk factor for breast cancer. The data are strongest for DDT. For PCBs, the results to date have been equivocal if not entirely negative. However, different groups of polychlorinated biphenyl (PCB) congeners are known to provoke biological responses that are structure specific. A wide divergence of estrogenic response, cytochrome P450 activity, and biological half-life exists within these groups of PCB congeners. Therefore, understanding breast-cancer risk from PCB exposure requires attention to congener structures in complex mixtures and to temporal changes in exposure. Investigation of environmental contributions to breast cancer risk offers the potential for understanding more about the etiology of this complex disease and may also provide opportunities for prevention of the most common cancer among women in the United States. -Environ Health Perspect 103(Suppl 7): 141-145 (1995)

Organochlorines and Risk of Prostate Cancer

“…It has been suggested that PCB 180 is a congener with activity like phenobarbital inducing CYP1A and CYP2B cytochrome P450 enzymes. 37,57 Interestingly, one epidemiologic study 62 found that CYP1A1 polymorphism may increase the risk of prostate cancer and two other studies 63,64 found a gene environment interaction for CYP1A1 polymorphism and PCB exposure for risk of breast cancer.…”

Lipid Adjustment in the Analysis of Environmental Contaminants and Human Health Risks

“…We set the independent effect of PCB as a constant (β lnPCB = 0.6 in the logistic regression model), with approximate values taken from the literature (Wolff and Toniolo 1995). In our unpublished data, we observed a significant linear relation between total serum PCBs and serum lipids with a regression coefficient value of approximately 0.3.…”

“…The human health effects literature on exposure to lipophilic agents such as organochlorines (OCs) is equivocal, impairing our ability to quantify risks (Calle et al 2002; Hunter et al 1997; Laden et al 2001a, 2001b). For example, Wolff and colleagues (Wolff 1985; Wolff and Toniolo 1995; Wolff et al 1993, 2000) found an increased odds ratio for breast cancer for the highest quintile of wet-weight dichlorodiphenyl-dichloroethylene (DDE) and polychlorinated biphenyls (PCBs; expressed as nanograms analyte per milliliter serum) when compared with the lowest quintile, whereas Laden et al (2001a, 2001b) found no association when concentrations of DDE and PCBs were standardized for serum triglycerides and cholesterol. No association was reported for PCBs and risk of breast cancer when expressing concentrations either as wet weight or lipid standardization values (Helzlsouer et al 1999).…”

Persistent organochlorine pesticide levels in bovine fat from Mexico

“…Thus, analysis of lipid-rich tissues indicates the magnitude of exposure and diffusion in the environment (Adeshima andTodd 1991, Sasaki et al 1991). The organochlorine pesticides, being hormonal disrupters capable of affecting the function of endocrine and reproductive systems of humans and wildlife, call the public's attention to their propagation (Ahlborg et al 1995, Fry 1995, Wolff and Toniolo 1995, Wolff and Weston 1997, Golden et al 1998, Hosie et al 2000, Safe 2000.…”