NFE2L2 and ovarian serous carcinoma: In line with this Nrf2–Cys–H2S regulatory axis, increased xCT and Nrf2 expressions are fully compatible with our previous reports unraveling that ovarian clear cell carcinoma cells (ES2) are especially dependent on cysteine metabolism compared to ovarian serous carcinomas (OVCAR3), to cope with stressful conditions such as hypoxia and drugs [25,57].