Exposure to
endocrine-disrupting chemicals, such as
polychlorinated biphenyls (PCB), may alter hormonal balance and thereby increase risk of testicular
germ cell tumors (TGCT). To study the relationship of
PCBs to TGCT, prediagnostic serum samples from 736 cases and 913 controls in the Servicemen's
Testicular Tumor Environmental and Endocrine Determinants study were analyzed. Adjusted odds ratios and 95% confidence intervals were estimated using logistic regression. PCB levels were examined in association with all TGCT and, separately, with each histologic type (
seminoma and nonseminoma). Risks associated with seven functional groupings of
PCBs, as well as sum of
PCBs, were also examined. There were significantly decreased risks of TGCT in association with eight
PCBs (PCB-118, PCB-138, PCB-153, PCB-156, PCB-163, PCB-170, PCB-180, and PCB-187) and no association with the remaining three (PCB-99, PCB-101, and PCB-183). The same eight congeners were significantly associated with decreased risk of nonseminoma, whereas five (PCB-138, PCB-153, PCB-156, PCB-163, and PCB-170) were associated with decreased risk of
seminoma. All functional groupings of
PCBs were also associated with decreased risk of TGCT and of nonseminoma, whereas six of the seven functional groups were associated with decreased risk of
seminoma. Sum of
PCBs was significantly associated with decreased risk of TGCT (P(trend) = 0.006), nonseminoma (P(trend) = 0.007), and
seminoma (P(trend) = 0.05). Overall, these data do not support the hypothesis that PCB exposure increases the risk of TGCT.