Although type 1 endometrial cancer has a better survival rate with treatment, while type 2 has a poorer prognosis with an aggressive form of the disease [2], our recent studies have found that there is no difference in the positivity of ER or PR as well as the sex hormone levels between type 1 and type 2 endometrial cancer [6, 7]. Here, ESR1 is linked to endometrial cancer.