Catalani S, et al. - Researchers conducted this systematic review and meta-analysis to examine if occupational and environmental exposure to polychlorinated biphenyls (PCBs) was connected with risk of non-Hodgkin lymphoma (NHL). Relative risks (RRs) was identified for PCB exposure and NHL risk in 30 populations (10 occupational exposure, seven high environmental exposure, 13 without special exposure) through a systematic search of the literature. According to findings, no connection was found between PCB exposure and NHL risk, particularly in occupational exposure studies. A weak dose-response relation was identified. It is not possible to rule out the possibility of residual ambiguity and other causes of prejudice. Among humans, PCBs are unlikely to cause NHL.