Its physiological roles are tissue-specific and can be both dependent and independent of its catalytic activity: kinase-dependent roles of ERK3 include promoting lung cancer cell migration and invasion, while its function in the regulation of breast cancer cell morphology and migration is shown to be partially kinase-independent (Al-Mahdi et al., 2015; Bogucka et al., 2021; Bogucka et al., 2020; Elkhadragy et al., 2020). The gene discussed is MAPK6; the disease is breast cancer.