PPARA and cancer: Because induction of cell proliferation is considered the mechanistic basis for the peroxisome proliferator-induced liver toxicity and tumorigenicity, it is likely that humans are not susceptible to such sequelae.40 The evidence of the lack of human relevance of PPARα MOA and liver tumors, together with the evidence that GenX acts through a PPARα MOA to induce mouse liver toxicity, has important implications in the human cancer hazard and risk assessment of GenX.