ESR1 and endometrial cancer: In the present study, knockdown of GPR30 in RL95-2 and Ishikawa endometrial cancer cells abrogated E2 and tamoxifen induced phosphorylation of FAK and abolished the subsequent cell migration (Figs. 2E, 2F, 3E and 3F), indicating that GPR30 is capable of mediating estrogen action in endometrial cancer cells with or without nuclear ERα.