MC4R and cancer: In advanced cancer patients, immune cells secrete large amounts of proinflammatory cytokines such as IL-1 and IL-6, which further exacerbates the progression of cachexia.346 Mechanistically, IL-1 triggers the release of α-MSH from POMC neurons347 and has an inhibitory effect on NPY neurons,348 which affects appetite by regulating MC4R expression in neurons.