TUMOR SURVEILLANCE - MISSING PEPTIDES AND MHC MOLECULES

Immunotherapy involving CTL is an attractive alternative for treatment of various malignancies. One of the approaches currently being explor ed for immune targeting of human cancers involves potentiation of immu nogenicity of malignant cells by gene transduction. This strategy is u ndoubtedly influenced by the ability of the malignant cells to endogen ously process and present target epitopes on their cell surface for im mune recognition by CTL. However, there is increasing evidence to sugg est that a large proportion of human cancers escape CTL-mediated immun e surveillance by selectively down-regulating the expression of MHC cl ass I molecules and peptide transporter genes. Understanding and molec ular analysis of these immunologically relevant genetic defects in tum ours is very important before translating preclinical studies of immun otherapy to rational clinical trials. Careful consideration of these p otential limitations may lead to the development of novel immunotherap eutic strategies and, potentially, prevention of tumour progression or development.