PTPN1 and obesity due to melanocortin 4 receptor deficiency: Because obesity and diabetes are regarded as inflammatory states characterized by the elevation of the pro-inflammatory cytokines Tumor necrosis factor α (TNFα), interleukin-1, and interleukin-6 in adipose tissue or sera [6], PTP1B may serve as an inflammatory target during obesity-associated inflammation [7]–[9].