In patients with endometrial cancer, the overall incidence of CCNE1 amplification was 5.06% (282/5574, Fig. 1A), with significant variation across histological subtypes (P < 0.05, Fig. 1B), including the highest rate in uterine carcinosarcoma (15.35%, 122/795), followed by uterine serous carcinoma (11.05%, 133/1204), clear cell carcinoma (4.04%, 8/198), and endometrioid tumors (0.56%, 19/3377). Here, CCNE1 is linked to endometrial serous adenocarcinoma.