We examined several proteins that can regulate muscle growth and are implicated in cancer cachexia, including STAT3 (Puppa et al., 2014), p38 MAPK (Ding et al., 2017; Brown et al., 2018), and ERK1/2 (Gao and Carson, 2016; VanderVeen et al., 2018). Here, MAPK3 is linked to cancer.