NFE2L2 and endometrial cancer: In this study, we examined the role of Nrf2 and AKR1C1 in the process of progestin resistance with the following approaches: 1) to test the level of Nrf2 and AKR1C1 protein expression in progestin treated endometrial cancer samples; 2) to examine the progestin resistance through up- or down-regulation of Nrf2 and AKR1C1 expression in 2 endometrial cancer cell lines; and 3) to test if the progestin resistance could be reversed by addition of metformin and brusatol, and the effects of these agents on Nrf2 and AKR1C1 expression.