HCV infection and liver cancer mortality in a Japanese population with HTLV-I

In a cohort study of human T-lymphotropic virus type I (HTLV-I) infection in Japan, 10 cases of liver cancer death occurred from 1984 through 1993. To analyze the role of hepatitis C virus (HCV), which has been associated with an increasing incidence of hepatocellular carcinoma (HCC) in Japan, a nested case-control study was performed. Five of the 10 liver cancer cases were positive for antibody to HTLV-I (anti-HTLV-I). The possible interaction between HCV and HTLV-I infections in the etiology of HCC was investigated, with each liver cancer case matched to 5 cohort controls by gender, age, serum sample date and anti-HTLV-I status. Using a matched analysis odds ratio (OR) were generated for the relationship between HCV serologic status and death liver cancer. Based on second-generation enzyme immunoassay with confirmation by recombinant immunoblot assay, 8 of 9 cases with adequate serum available (89%) and 9 of 50 (18%) controls were found to be positive for antibody to HCV (anti-HCV). Liver cancer death was highly associated with anti-HCV (matched OR = infinity; p < 0.001). Anti-HTLV-I seroprevalence was some what correlated with HCV infection. However, the high risk of liver cancer death observed for anti-HCV-positive Individuals in this population did not vary with respect to whether or not the subjects were also infected with HTLV-I.