PPARD and obesity due to melanocortin 4 receptor deficiency: According to all these data, PPARβ/δ agonists (GW501516, GW0742, L-165041 and MBX-802) may be considered as possible future targets for the therapy of metabolic syndrome and obesity, T2DM and cardiovascular diseases; however, in this moment, none of these molecules are used in human trials because of their contradictory data on tumorigenesis [18].