Current Status of the Epidemiologic Evidence Linking Polychlorinated Biphenyls and Non-Hodgkin Lymphoma, and the Role of Immune Dysregulation

Abstract

Background: Although case–control studies conducted to date have largely affirmed the relationship between polychlorinated biphenyls (PCBs) and non-Hodgkin lymphoma (NHL), occupational cohort studies of PCB-exposed workers have been generally interpreted as negative, thereby raising doubts about a potential causal association. A common theme of immune dysregulation unifies many of NHL’s strongest risk factors, and several authors have posited that subclinical immune dysregulation may increase NHL risk by decreasing host resistance, reducing control of cellular proliferation and differentiation, and diminishing tumor surveillance mechanisms.Objectives: The goals of this review were a) to evaluate the epidemiological research examining the association between PCB exposure and NHL and discuss the contribution to the weight of evidence of case–control studies and occupational cohort studies; and b) to summarize the evidence for immune dysregulation as a means by which PCBs may cause NHL.Methods: We performed a literature search using PubMed and seven additional online biomedical and toxicological referencing libraries to identify literature published through August 2011.Discussion and Conclusions: Overall, we conclude that the weight of evidence supports a causal role of PCBs in lymphomagenesis. The strongest epidemiological evidence for the relationship between PCBs and NHL comes from case–control studies conducted among the general population. Epidemiological and toxicological data demonstrating immunosuppressive and inflammatory effects of PCBs further contribute to the weight of evidence by providing a plausible explanation for how PCBs can cause NHL through immune dysregulation.

Serum polychlorinated biphenyls and leukocyte telomere length in a highly-exposed population: The Anniston Community Health Survey

“…In a cohort study of 24,865 capacitor-manufacturing workers exposed to PCBs mortality from melanoma was elevated among those employed for three months or more [standardized mortality ratio= 1.41, 95% CI 1.01;1.91] (Ruder et al, 2014). Case-control studies, including nested case-control studies that measured PCBs prior to diagnosis of NHL, have generally reported that exposure to PCBs are associated with an increased risk of NHL (reviewed by: (Kramer et al, 2012)). An analysis of three nested case-control studies from three prospective cohort studies reported that serum PCBs were consistently associated with elevated risk of NHL.…”

Blood Erythrocyte Concentrations of Cadmium and Lead and the Risk of B-Cell Non-Hodgkin’s Lymphoma and Multiple Myeloma: A Nested Case-Control Study

“…In particular, polychlorinated biphenyls (PCBs) and dioxins have been implicated in studies of occupationally exposed cohorts or populations living in the vicinity of industrial sources of these pollutants. This association is supported by the temporal relationship between worldwide usage and incidence trends of NHL [13]. Similarly, there is evidence for an increase of NHL incidence in populations living near refineries that emit Pb and Cd [14].…”

Chemical and microbiological characterization of an aged PCB-contaminated soil

“…Moreover, owing to their aforementioned inertness, PCBs are still present in a number of areas where their production has been carried on for decades, although their application was drastically restricted in the 1970-1980s. At the present time, PCBs are considered to belong to the most hazardous contaminants in the world, placing them at the forefront of public health concern (Ross, 2004). Indeed, the teratogenic, carcinogenic Science of the Total Environment 533 (2015) [177][178][179][180][181][182][183][184][185][186] and endocrine-disrupting features of these xenobiotics have been widely reported in the literature (Crinnion et al, 2011;El Majidi et al, 2013;Helmfrid et al, 2012;Kramer et al, 2012;Muscat et al, 2003;Svobodová et al, 2009).…”