PPARA and neoplasm: Another area of active investigation has been whether PPARα agonists activate nonparenchymal liver cells such as Kupffer cells independently of PPARα activation and whether such activation may be necessary for tumor induction, particularly due to their role in parenchymal cell proliferation and apoptosis suppression (Hasmall et al. 2001; Holden et al. 2000; Parzefall et al. 2001; Peters et al. 2000; Roberts et al. 2002; Rusyn et al. 2000, 2001).