MAPK6 and cancer: Increased ERK3 abundance or activation is associated with increased migration of breast cancer and head and neck cancer cells, whereas ERK3 deletion or knockdown decreases the migration and invasion of lung, cervical, and mammary cancers or cancer cell lines (Al‐Mahdi et al., 2015; Elkhadragy et al., 2017, 2018; Long et al., 2012; Wang et al., 2014; Wu, Zhao, et al., 2019) yet enhances the migration of myeloma or A‐431 cell lines (Alshammari et al., 2021; Chen et al., 2019).