MAPK3 and breast carcinoma: Specifically, p38 signaling was downregulated in neuroblastoma via inhibition of dual-specificity protein phosphatase 26 (DUSP26) (35), mitogen induced ERK1/2 activation was downregulated in breast cancer cells (31), and JNK activity was downregulated in CD8+ T cells in murine encephalomyelitis (36).