MAPK3 and neoplasm: MSC-derived exosomes can promote tumor development in a variety of solid tumors through their internal miRNAs (Du et al., 2014; Zhao et al., 2019; Zhou et al., 2019), which appears to be associated with the activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway (Zhu et al., 2012).