MAPK8 and cancer: We confirmed the co-occurrence of MAP2K7 deletion and low pJNKT183/Y185 activity in the TCGA breast cancer cohort (n = 616) [32, 37] where JNK phosphorylation was, on average, 37.5% lower in ER+ breast cancers with a MAP2K7 homozygous or heterozygous loss compared to those cancers with no loss of MAP2K7 (diploid, amplified or gain status) (p = 0.0002; Fig. 2J).