13-cis-retinoic acid: effect on urinary bladder carcinogenesis by N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide in Fischer rats.

The failure of 13-cis-retinoic acid to inhibit either the incidence or severity of bladder carcinoma in female Fischer rate initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) suggests that inhibition of bladder carcinogenesis by natural and synthetic retinoids is carcinogen-class specific, and adds an element of complexity to approaches in chemoprevention.