Expression of cancer-testis antigen (CTA) in tumor tissues and peripheral blood of Chinese patients with hepatocellular carcinoma.

To investigate the expression of cancer-testis antigen (CTA) in Chinese patients with hepatocellular carcinoma (HCC), and the relationship between CTA gene expression and clinical indexes, we used one-step reverse transcription polymerase chain reaction (RT-PCR). The expression of the CTA mRNA was investigated in the tissues of HCC and corresponding peripheral blood of 37 patients with HCC. Fifteen samples of cirrhotic tissues and 15 normal tissues were examined with the same method. Two kinds of CTA (SSX-2 and SSX-5) showed high-specific and high-frequent expression in HCC tissues, but neither of them could be detected in adjacent non-HCC tissues. In corresponding peripheral blood of HCC tissues, the positive expression rate of the SSX-2 and SSX-5 mRNA was not very high. No relationship was found between the expression of CTA and clinical indicators such as age, sex, tumor size, TNM staging, serum AFP level and infection with hepatitis virus. In 15 patients with cirrhosis and 15 other non-tumor patients, none of the SSX-2 and SSX-5 mRNA was detected in liver tissue or peripheral blood. High frequency and specificity of CTAs in HCC indicates that their products may be new potential promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of the two genes in HCC provides a possibility of polyvalent vaccinations for HCC. Specific expression of CTAs was observed in AFP-negative HCC, suggested applying their mRNA as tumor markers to detect circulating HCC cells as adjuvant diagnostic tool and as indicators of recurrence and prognosis.