As a common effector of TLR4 and inflammatory cytokine receptors that promote muscle wasting including TNFα (Li et al., 2005), IL-6 (Hetzler et al., 2015), IL-1β (Li et al., 2009) and members of the TGFβ superfamily including TGFβ (Waning et al., 2015) and activin A/myostatin (Ding et al., 2017; Zhong et al., 2019), p38β MAPK plays a central role in mediating muscle wasting in murine models of cancer (Sin et al., 2019b; Sin et al., 2021). The gene discussed is IL1B; the disease is cancer.