Indeed, as shown, (1) diabetes and obesity are important cancer comorbidity factors; (2) PPARs are involved in lipid and glucose metabolism; (3) PPARγ and PPARβ/δ regulate the expression level of inflammatory cytokines and adipokines, such as leptin and ANGPTL4; (4) the deregulation of PPAR isoforms was detected in different types of cancer; (5) the ANGPTL4 expression depends on the PPAR stimulus. This evidence concerns the gene LEP and diabetes mellitus.