MAPK8 and cancer: Our study also showed that constitutive GADD45β expression is largely restricted to cancer cells, where it fosters cell survival by means of its physical interaction with and inhibition of the MAP JNK kinase, mitogen-activated protein kinase kinase 7 (MKK7, Uniprot AC: O14733; 419 amino acids; Molecular mass 47,485 Da), an essential activator of the pro-apoptotic JNK signalling pathway [[2], [3], [4], [5]].