FOXK2 and obesity due to melanocortin 4 receptor deficiency: Based on the observation that ELF and ILF have specific lipid-peaks in patients with malignant pancreatic tumors and that ILF lipid-peaks were related to obesity, we hypothesized that the ELF and the ILF in OB patients could play a role in the initiation of precancerous pancreatic lesions (PanINs).