RESUMO
HLA antigen expression can show close relationship with some kinds of tumor cell immunologically. We investigated the relationship between the grade of bladder transitional cell carcinoma and HLA-DR expression to demonstrate the prognostic significance. Paraffin-embedded samples from 25 human transitional cell carcinoma cases were examined for the expression of MHC class R antigen with monoclonal antibody directed against HLA-DR using immunohistochemical methods. The tumors were classified according to the Ash grading system and the degree of the peritumoral mononuclear infiltrates. Both diffuse cytoplasmic and membrane HLA-DR staining were observed in 6 or 17 low grade (Grade I, II) tumors. All 8 high grade (Grade II IV)transitional cell carcinoma exhibited negative staining for HLA-DR antigen. Apart from the relatively high incidence of the positive expression of HLA-DR in low grade tumors, no clear statistical relationship was found between the expression or HLA antigens and the tumor grade. From these results, it may be suggested that the low grade transitional cell carcinoma shows a high incidence of HLA-DR expression and prognostic significance induced by immune response; T cell-mediated immune response against TCC proliferation is evoked. But the significance of these findings remains speculative at present. Therefore, further study should be performed to demonstrate the prognostic importance of HLA-DR expression in transitional cell carcinoma of the bladder.