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 an alyzed in 65 renal cell carcinomas using one-dimensional isoelectric f ocusing. Normal organ tissue and peripheral blood lymphocytes were use d as controls. The patients were serologically typed using the standar d microcytotoxicity test. Forty-two patients, were staged as pT(1) or pT(2), and 23 patients had advanced tumor stages (pT(3)/pT(4)). In all cases the HLA-A,B phenotypes were confirmed using one-dimensional iso electric focusing. The expression of HLA expression was reduced in two tumors [1 x HLA-A1(pT(2)); 1 x HLA-A28 (pT(2))]. In three carcinomas the expression of HLA-AL,vas lost. One tumor showed a combined loss of HLA-A2 and HLA-B38. These selective losses occurred in tumor stage pT (3) (n = 1) or pT(4) (n = 3; P = 0.013, Fisher's exact test). This lea ds to the conclusion that the loss of HLA expression is predominantly present in advanced tumor stages.