Emergence of an epidermis-associated cell surface antigen in epithelial cells of the rat urinary bladder in carcinogenesis.

Inbred ACI/rats were treated with a selective urinary bladder carcinogen N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Two cell surface antigens on the epithelial cells of the bladder, normal bladder epithelium (NBE) antigen unique to normal epithelial cells of the bladder and BC-SK antigen specific for bladder cancer and epidermis, were periodically assayed by mixed hemadsorption test with the typing sera against each antigen. Treatment with BBN for 8 or more weeks induced papillomas or cancers that expressed a definite level of BC-SK antigen, whereas a 4-week treatment did not render the bladder cells with a significant level of this antigen. In general, the level of NBE antigen in bladder cells was not altered by the BBN treatment. In vitro culture of bladder cells of BBN-treated rats resulted in an increase in the level of BC-SK antigen as opposed to a decrease in the NBE antigen level. BC-SK antigen was not detected in epidermal cells of rats younger than 3 days, but it emerged in these cells by in vitro culture for longer than 4 days.