We have initiated the research program of tumor immunology since late 1997.It is to aim at the biotherapy and diagnosis by immunological means in cancer patients,and to scrutinize the biological events of tumorigenesis.The gene mRNAs encoding 10 known CT (cancer testis) antigens have been analyzed for the expression patterns in human hepatocellular carcinoma (HCC) and found that HCC expressed multiple types of CT antigen mRNA.In the clinical follow up monitoring of HCC progression,the kinetic test of MAGE 1 and MAGE 3 mRNAs detectable in PBMCs has provided a reliable tumor specific maker to anticipate the prognosis of HCC patients. A variety of technologies have been employed to identify tumor antigens exressed in HCC.In the SEREX (Serological Analysis of Recombinant Expression cDNA Library) cloning,we have identified and characterized 2 novel CT antigens and their encoding genes.Combination of bioinformatics and molecular biology,we have identified 2 novel CT antigens and one tumor specific antigen.Some other tumor antigens identified may be implications in the diagnosis of cancers of various types. Immune response of HCC patients to NY ESO 1 and MAGE 3 peptides bound to HLA A2 has been evaluated.The supertype of HLA A2 has been defined for HLA A#0201 binding flu matrix peptide.All these support the feasibility of the application of tumnor antigenic peptide vaccine for immunotherapy in HCC patients.