The JNK pathway has a dual role in different types of cancers, including hepatocellular carcinoma (HCC), pancreatic cancer, prostate cancer, multiple myeloma and oral cancer, non-small-cell lung cancer (NSCLC), glioblastoma, papilloma, intestinal tumors, breast cancer, squamous cell carcinoma, Burkitt’s lymphoma, and ovarian cancer [1,9,26,57,114,159]. The gene discussed is MAPK8; the disease is plasma cell myeloma.