In cancer cells, members of the MAPK family, including MEK/ERK, p38, and c-Jun N-terminal kinase (JNK), are phosphorylated and translocated from the cytoplasm to the nucleus to activate cell proliferation and regulate various downstream substrates, including MMP-2, MMP-9, and EMT-associated genes (27–29). Here, MAPK8 is linked to cancer.