PPARA and liver cancer: Past reviews of the PPAR-α activation MOA hypothesis have generally focused on liver cancer response in two fibrate clinical trials, the Helsinki Heart Study (Frick et al. 1987; Huttunen et al. 1994; Tenkanen et al. 2006) and the World Health Organization’s Cooperative Trial on Primary Prevention of Ischemic Heart Disease (Committee of Principal Investigators 1978, 1980, 1984), and have concluded that, although limited, those data did not provide evidence of an increased liver cancer risk from fibrate exposure (Ashby et al. 1994; Klaunig et al. 2003).