This mode of action hypothesis (Figure 3),comprising 2 nonexclusive mechanisms (Figure 1(b), (i) and (iii))was in agreement with coexpression of PPARα and γ by the urothelium [17, 18, 38],with the known propensity of various PPAR agonists to exhibit cytotoxic effects[36, 61, 62],and with the known positive correlation between cytotoxic and carcinogeniceffects for some small molecule drugs [63, 64].Similarly, it was concluded for naveglitazar-induced bladder cancer in ratsthat a mechanism involving a direct effect of the compound on PPARs in theurothelium should be considered [31]. Here, PPARA is linked to urinary bladder cancer.