MAPK3 and cancer: Several synthetic inhibitors of ERK1/2, such as PD98059, PD184161, VTX-11e, FRI-20, ON-01060 [79], pirfenidone [80], bisphenol A, and 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane [81], as well as natural products such as krukovine [82], globularifolin [8], tanshinone IIA [10], reduce cancer cell proliferation in vitro.