MAPK8 and neoplasm: However, in cancer cell lines, PDCD6 could mediate the inhibition of ASK1/JNK pathway through Raf-1 (Raf-1 protooncogene, serine/threonine kinase), thereby increasing tumor sensitivity to chemotherapy, and Raf-1 was required for MEK/2 activation under proapoptotic conditions [52].