Expression of major histocompatibility complex (MHC) antigens and their loss on culture in renal carcinoma.

Biopsies from the tumour and the adjacent normal kidney were obtained from 15 patients with renal cell carcinoma (RCC). The proximal convoluted tubules from which the tumour arose expressed major histocompatibility complex (MHC) class I antigen (Ag) in 3 cases and class II in none. By contrast, the carcinoma cells expressed class I Ag in 14 cases and class II Ag in 5 cases. Cells from each carcinoma were established in culture. As the culture period increased, cells from six of eight RCC showed diminished expression of class I Ag and five of six reduced expression of class II Ag. This is similar to the relative loss of class I Ag in synchronous metastases from RCC.