[Immunologic modulation of tumor aggressiveness in cancer of the larynx. I. Genetic and molecular studies of HLA class I antigens]

Abstract

A series of 60 primary laryngeal and hypopharyngeal tumours, 24 lymph node metastasis and normal tissue were evaluated in frozen sections for the expression of MHC class I antigens, using monoclonal antibodies. Normal distant mucosa of the larynx reacted to anti class I antibodies. In 13 primary tumours HLA class I antigens were not found. The remaining 47 showed a strong reaction to anti HLA-ABC (heavy chain) and anti beta 2-microglobulin, although in 5 cases staining was not observed with anti HLA-A locus specific monoclonal antibodies. Other tumour showed a selective loss of HLA-B antigens. These selective losses were confirmed using the correspondent anti-HLA polymorphic monoclonal antibodies. We have found differences in HLA class I expression when comparing primary tumours and autologous metastasis (3/15 cases). Finally, to further analyse the mechanism responsible for the HLA phenotypic changes observed, immunoprecipitation and SDS-PAGE of class I antigens, Northern and Southern blot analysis of MHC class I genes were performed. We have not detected class I gene rearrangement using HLA coding and locus specific non coding probes. However we have found a class I transcription defect in a class I negative tumour.