PPARA and nonpapillary renal cell carcinoma: To investigate whether the modulation of PPAR-α activity can modulate the expression of miR-21, ccRCC cell models were exposed to GW7647, a highly selective PPAR-α agonist, and also transiently transfected by the pSG5-PPAR-α expression vector containing PPAR-α cDNA without a putative miR-21 binding site in its 3′-UTR.