Plasma levels of polychlorinated biphenyls and risk of cutaneous malignant melanoma: A hospital-based case-control study

Polychlorinated biphenyls (PCB) have been classified by the International Agency for Research on Cancer (IARC) in Group 1 as carcinogenic to human, based on sufficient evidence in humans of an increased risk of cutaneous malignant melanoma (CMM), however few studies have been done in the general population. This study examined the relationship between PCB plasma levels and risk of CMM adjusting for sun sensitivity and sun exposure in a province of Northern Italy (Brescia), where a chemical factory produced PCBs from 1938 to 1984 causing human contamination. A case-control study of 205 CMM patients and 205 control subjects was conducted. Cases and controls were assayed for plasma levels of 33 PCB congeners. No associations was found between risk of CMM and plasma levels of total PCB (OR = 0.81; 95% CI: 0.34-1.96 for highest vs lowest quartile) or specific congeners. The study confirmed the association with light skin colour (OR = 3.00; 95% CI: 1.91-4.73), cumulative lifetime UV exposure (OR = 2.56; 95% CI: 1.35-4.85) and high level of education (OR = 1.45; 95% CI: 1.03-2.05). This case-control study does not support the hypothesis of an association between current plasma levels of PCBs and CMM development in the general population.