HLA class I antigens expression in renal cell carcinoma: Histopathologicaland clinical correlation

Immunohistochemical analysis of HLA class I antigens expression in 26 renal cell carcinomas (RCCs) - 18 clear cell, 6 granular and 2 chromophobe - was performed with indirect immunoperoxidase method. Results were correlated w ith extent and immunophenotype of tumor infiltrating mononuclear cells, his topathological (histology, cytology, grade, presence of necrosis) and clini cal (tumor diameter, TNM classification) characteristics of RCC. 4 (15%) RC Cs showed reduced HLA class I presence and this was associated with greater tumor diameter and more frequent T3,T4 and M1 stage, All tumors with alter ed HLA class I antigens expression were grade 2 or 3 and strong correlation with presence of necrosis (p=0,006) was noticed, while mononuclear cell in filtrates (especially CD8+ T lymphocytes) were less extensive compared to t umors with normal HLA class I level. Our results suggest more aggressive cl inical behavior of RCCs with reduced HLA class I antigens expression, proba bly due to impaired cellular antitumor immune response.