Association study between plasma levels of polychlorinated biphenyls and risk of cutaneous malignant melanoma.

Cutaneous malignant melanoma (CMM) ranks the most lethal skin cancer worldwide. However, other risk factors have been hardly explored, aside from ultraviolet radiation (UVR). Polychlorinated biphenyls (PCBs) were implied to be potential risk factors for CMM, although all the evidence was obtained from the western countries. This study examined the relationships between plasma levels of PCBs and CMM risk adjusting for sun sensitivity and sun exposure in a Chinese population, using a case-control study, including 450 CMM cases and 500 healthy controls. Plasma levels of a total of 33 PCB congeners were assayed in both cases and controls. Our results showed that there was a significant association between total summed PCB level and CMM risk, with a 1.44-fold increased risk for those in the highest quartile compared to those in the lowest quartile (OR = 1.44, 95% CI: 1.02-2.03, P for trend = 0.031). Significantly increased ORs were also observed for individual PCB congeners (PCB52, PCB170 and PCB180). These associations persisted after control for sun sensitivity and sun exposure. Our study represents the first evidence conducted in Asians, and does support the hypothesis that PCB exposure increases CMM risk.