New Exposure Biomarkers as Tools for Breast Cancer Epidemiology, Biomonitoring, and Prevention: A Systematic Approach Based on Animal Evidence

Abstract

Background: Exposure to chemicals that cause rodent mammary gland tumors is common, but few studies have evaluated potential breast cancer risks of these chemicals in humans.Objective: The goal of this review was to identify and bring together the needed tools to facilitate the measurement of biomarkers of exposure to potential breast carcinogens in breast cancer studies and biomonitoring.Methods: We conducted a structured literature search to identify measurement methods for exposure biomarkers for 102 chemicals that cause rodent mammary tumors. To evaluate concordance, we compared human and animal evidence for agents identified as plausibly linked to breast cancer in major reviews. To facilitate future application of exposure biomarkers, we compiled information about relevant cohort studies.Results: Exposure biomarkers have been developed for nearly three-quarters of these rodent mammary carcinogens. Analytical methods have been published for 73 of the chemicals. Some of the remaining chemicals could be measured using modified versions of existing methods for related chemicals. In humans, biomarkers of exposure have been measured for 62 chemicals, and for 45 in a nonoccupationally exposed population. The Centers for Disease Control and Prevention has measured 23 in the U.S. population. Seventy-five of the rodent mammary carcinogens fall into 17 groups, based on exposure potential, carcinogenicity, and structural similarity. Carcinogenicity in humans and rodents is generally consistent, although comparisons are limited because few agents have been studied in humans. We identified 44 cohort studies, with a total of > 3.5 million women enrolled, that have recorded breast cancer incidence and stored biological samples.Conclusions: Exposure measurement methods and cohort study resources are available to expand biomonitoring and epidemiology related to breast cancer etiology and prevention.Citation: Rudel RA, Ackerman JM, Attfield KR, Brody JG. 2014. New exposure biomarkers as tools for breast cancer epidemiology, biomonitoring, and prevention: a systematic approach based on animal evidence. Environ Health Perspect 122:881–895; http://dx.doi.org/10.1289/ehp.1307455

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

“…Therefore, the higher incidence of breast cancer in the UOQ may not be attributable to bioaccumulation of PCBs; however, humans carry mixtures of many environmental chemicals and combination effects resulting from the interaction of these pollutants may have detrimental health effects (Porta et al, 2012). Further research is needed to evaluate relationships between the rising incidence of breast cancer in humans and an array of other potential carcinogens that are known to cause mammary tumors in rodents (Rudel et al, 2014).…”

BCScreen: A gene panel to test for breast carcinogenesis in chemical safety screening

“…Currently, the Mammary Carcinogens Review Database names over 200 chemicals considered to be mammary carcinogens (MCs) based on increased mammary gland tumors in animal studies [40,39]. However, many commercial and industrial chemicals have not been evaluated for breast cancer risk at any level.…”

Hypothesis: Activation of rapid signaling by environmental estrogens and epigenetic reprogramming in breast cancer

“…It has been hypothesized that the increase in the incidence of breast cancer during the last 50 years may be due to environmental exposures, most notably to hormonally active chemicals often categorized as endocrine disrupting compounds (EDCs) [5]. In fact, such compounds have been identified as priority chemicals, among others, for future breast cancer research [6]. …”