MAPK8 and cancer: Immunohistochemical analysis for the expression of IL-1RA, Ki-67 (a cancer proliferation marker [40]), p-EGFR, p-JNK, and SOX2 revealed that IL-1RA expression remained high in the xenograft tumors collected from the mice groups with IL-1RA-overexpressing OECM-1-luc cells (Fig. 7C), whereas the elevated expression of IL-1RA-associated Ki-67, p-EGFR, p-JNK, and SOX2 was reduced in the groups treated with metformin, CDDP, or a combination of both (Fig. 7D–G).