BCG-induced enhancement of tumor growth in experimental bladder tumor model

Transitional-cell carcinoma of the bladder has been induced by chronic oral administration of N-(4-(5-nitro-2-furyl)-2 thiazolyl) formamide (FANFT) in C3H/He mice, and successfully transplanted in syngeneic animals. Treatment was attempted under 2 major categories, namely, by preimmunization with tumor antigens or BCG, and by BCG administration through different routes. Classic tumor challenge experiments showed the presence of tumor associated antigens on FANFT tumor cells. In this present study, BCG treatment promoted rather than inhibited the growth of FANFT tumor. Some proposed explanations for mechanism (s) of tumor enhancement following BCG immunostimulation were discussed.