Selective loss of human leukocyte antigen class I allele expression in advanced renal cell carcinoma

The expression of human leukocyte antigen (HLA) class I alleles was analyzed in 65 renal cell carcinomas using one-dimensional isoelectric focusing. Normal organ tissue and peripheral blood lymphocytes were used as controls. The patients were serologically typed using the standard microcytotoxicity test. Forty-two patients were staged as pT1 or pT2, and 23 patients had advanced tumor stages (pT3/pT4). In all cases the HLA-A,B phenotypes were confirmed using one-dimensional isoelectric focusing. The expression of HLA expression was reduced in two tumors [1 x HLA-A1(pT2); 1 x HLA-A28 (pT2)]. In three carcinomas the expression of HLA-A1 was lost. One tumor showed a combined loss of HLA-A2 and HLA-B38. These selective losses occurred in tumor stage pT3 (n = 1) or pT4 (n = 3; P = 0.013, Fisher's exact test). This leads to the conclusion that the loss of HLA expression is predominantly present in advanced tumor stages.