TNF and Cachexia: Among the factors secreted both by the tumour and the peripheral organs/tissues, those reported to be consistently and frequently changed in cachexia, are tumour necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and growth differentiation factor 15 (GDF15), all of which promote muscle degradation and insulin resistance (IR) [13,24,25].