GDF15 and Cachexia: Previous studies focusing on the identification of intra‐organ and inter‐organ mechanisms responsible for tissue wasting have identified some tumour‐derived and host‐derived factors as cachexia mediators, notably including pro‐inflammatory factors such as interleukin‐6 (IL‐6), tumour necrosis factor‐α, interleukin‐1β, or growth differentiation factor 15 (GDF‐15).1