Tumorigenic and metastatic ability of SV40-transformed BALB/c cell lines and MHC antigen expression.

Tumorigenic and metastatic potential were studied in relation to class I MHC expression in four different SV40-transformed BALB/c cell lines. All the lines studied, tumorigenic or not, expressed both H-2Kd and Dd, so MHC antigens did not seem to be involved in the control of SV40-transformed cells' growth in vivo. Lung metastases were observed in all tumour-bearing mice. Cells cultured after in vivo passage, obtained either from tumour tissue or from individual lung metastases, still expressed similar levels of H-2d antigens, thus suggesting that tumour growth and metastasis do not occur through the selection of variants with altered MHC expression.