Grau et al. found that ligand-based PPARα activation in colorectal cancer cells inhibited transcriptional induction of COX-2 and vascular endothelial growth factor (VEGF) [30], with the mechanism thought to involve inhibition of induction of activator protein-1- (AP-1-) dependent genes, which are involved in tumor progression. This evidence concerns the gene PTGS2 and colorectal cancer.