IL1A and cancer: The UPR system is specifically up‐regulated by skeletal muscle cells during cancer cachexia through the expression of ubiquitin‐ligases: the muscle RING finger‐containing protein 1 (MURF1) and Atrogin‐1.15, 69, 82, 83 The expression of these ligases involved in muscular proteolysis and muscle wasting is increased by the activation of forkhead box O (FOXO) family transcription factors.3, 15 FOXO activation occurs via NF‐κB signalling, which is activated by cytokines such as TNF‐α and IL‐1 and by proteolysis‐inducing factor (PIF).3, 15, 84