To further investigate whether the PKMYT1i-ATRi combination is dependent on Cyclin E1 protein level, we established and then tested drug effects in immortalized fallopian tube cells and ovarian and endometrial cancer cell lines, with and without CCNE1 overexpression (FT282 with CCNE1 overexpression, WO-20 with inducible CCNE1 and SNU685 with inducible CCNE1)11. This evidence concerns the gene CCNE1 and endometrial cancer.