MAPK3 and lung cancer: The fibroblast growth factor 8 (FGF8)/FGF receptor 1 (FGFR1)/extracellular signal-regulated kinase 1/2 (ERK1/2) axis functions in the tumorigenesis in various tumors, including lung cancer, and its role involves involved in the invasion, metastasis and progression of non-neoplastic lesions.