Polychlorinated Biphenyls and Cancer: An Epidemiological Assessment

Abstract

Polychlorinated biphenyls (PCBs) are toxic and persistent chemicals produced between 1930s and 1980s primarily for insulating fluids in heavy-duty electrical equipment in power plants, industries, and large buildings. They persist in the environment and accumulate in plants and animals, and have been classified as probable carcinogens to humans. We performed a systematic review and meta-analysis of scientific literature on the relationship between PCB exposure and human cancer. Two cohorts of people highly exposed to PCBs through ingestion of contaminated rice oil and some cohorts of occupationally exposed workers failed to show a definite increase in total cancer mortality and provided inconsistent results regarding single cancers. Several cohort and case-control studies investigated the association between PCBs and specific cancers, showing an association between PCB serum levels and non-Hodgkin lymphomas (NHL), with a summary odds ratio of 1.5 (95% confidence interval: 1.1-1.7), but no consistent results for the other cancer sites and types. In conclusion, this review provides some evidence for the role of PCBs in the development of NHL, although the inconsistent results of studies performed on highly polluted people and occupationally exposed workers do not allow a firm conclusion to be drawn.

Phenotypic malignant changes and untargeted lipidomic analysis of long-term exposed prostate cancer cells to endocrine disruptors

“…Numerous studies have demonstrated a relationship between PCBs exposure and a variety of toxic effects, such as carcinogenicity, teratogenicity or reproductive toxicology in animals (Bell, 2014;El Majidi et al, 2014;Zani et al, 2013). Also, correlation between environmental and occupational exposures to PCBs and human prostate cancer has been reported (Kling et al, 1978;Hessel et al, 2004).…”

A Review on Thiazolidinediones and Bladder Cancer in Human Studies

“…Humans can be exposed to environmental and anthropogenic carcinogens [12][13][14][15][16][17][18][19][20][21][22], and diabetic patients may have a higher risk for a variety of cancers [23][24][25][26][27][28][29][30][31][32][33][34]. Diabetes is increasing in prevalence and incidence and affects hundreds of millions of people worldwide [35][36][37].…”

Hepatocellular carcinoma and the risk of occupational exposure

“…Other studies in workers exposed to the PCB have reported an increased incidence of liver tumors [185][186][187][188] . Some possible mechanisms by which PCB can cause cancer have been assumed: Reactive oxygen species (ROS) is produced through the enzymatic oxidation or autoxidation of PCB; PCB determines the increased expression of genes responsible for inflammation and apoptosis in the liver; and PCB has "toxic" effects on certain genes, such as the loss of part of a chromosome and chromosome breakage [189][190][191][192][193][194][195][196][197][198][199] . ROS are also able to reduce telomerase activity which can determine telomere shortening.…”