Moreover, Nanki et al. (2001) suggested that CCL2 enhances extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) activation due to CCR2 and, therefore, induces IL-6 production by fibroblast-like synoviocytes in rheumatoid arthritis. This evidence concerns the gene CCR2 and rheumatoid arthritis.