Kito et al. [28] reported that cyclic strain-induced IL-6 production is regulated by p38, ERK, and JNK in endothelial cells, whereas Amin et al. [20] reported that IL-18-induced MCP-1 production in synovial fibroblasts of patients with rheumatoid arthritis is mediated by JNK, but not p38. This evidence concerns the gene MAPK8 and rheumatoid arthritis.