Other authors demonstrated that HFD can induce LGR5 expression, stem cell transformation, and colon carcinogenesis in a xenograft model of colon cancer independent of obesity through a vitamin A-bound serum retinol binding protein 4-stimulated by retinoic acid 6 (RBP4-STRA6) signalling pathway [35]. Here, RBP4 is linked to obesity due to melanocortin 4 receptor deficiency.