In this study, we clearly demonstrated that GnRH-I or GnRH-II resulted in a significant increase in the phosphorylation of ERK1/2 and p38 in HEC1A cells, suggesting these MAPKs are involved in GnRH-I or GnRH-II induced cell growth inhibition of endometrial cancer cells. This evidence concerns the gene MAPK3 and endometrial cancer.