MAPK3 and neoplasm: They are fully competent as ligands, which then bind/activate tumor EGFR (ErbB1-4) receptors to trigger oncogenic signaling: (phosphatidylinositol 3-kinase/Akt, Ras/Raf/MEK/ERK1/2, and phospholipase C), which also leads to sustained release of cytokines that cause leukocyte infiltration to the tumor microenvironment (TME) [81,82].