TP53 and cancer: In OVCAR-3 cells, the ethyl acetate fraction of the 95% ethanol extract of O. japonica enhanced the mRNA levels of the tumor suppressor p53 and CDK inhibitor p21 through the effective combination of p-p38 and p-extracellular-signal-regulated kinase (ERK)1/2 MAPK, resulting in cell arrest during the G1/S phase and thus inhibiting cancer cell proliferation.