Abstract:

Objective: To summarize the clinicopathological characteristics of uterine serous carcinoma (USC), and to investigate its molecular classification and human epidermal growth factor receptor 2 (HER2) expression. Methods: The clinical data of 20 USC patients were collected. HE, immunohistochemistry, Sanger sequencing and FISH were used to detect in USC patients, and the molecular typing and HER2 expression were analyzed. Results: USC accounted for 8% of endometrial cancers, with FIGO stage Ⅰ in 5 cases (25%), stage Ⅱ in 1 case (5%), stage Ⅲ in 9 cases (45%), and stage Ⅳ in 5 cases (25%). Three histological structures of papilla, glandular and solid were seen in the carcinoma tissue. The nipple is wide or small, the cells are easy to fall off, the edge is not smooth and the glandular lumen is mostly fissured. The cytoplasm was clear or eosinophilic and vascular invasion was observed in 13 cases (65%). The positive rates of ER, PR, Vimentin, WT1 and P16 were 40%, 25%, 10%, 35% and 100%, respectively, and the positive rates of Ki-67 were 30%-80%. POLE mutation was not detected in 20 UCS patients, MLH1, PMS2, MSH2 and MSH6 were all positive. There were 16 cases (75%) with P53 missense mutation and 4 cases (25%) with nonsense mutation. HER2 3+ was labeled by immunohistochemistry in 5 cases (25%), and amplified signal was detected by FISH in 4 cases. Conclusions: The incidence of USC was low and the pathological morphology of USC was diverse. Immunohistochemical staining was helpful for its diagnosis. The molecular typing of USC was abnormal P53, and HER2 was expected to be a therapeutic target.

Key words: Uterine serous carcinoma, POLE, P53, Human epidermal growth factor receptor 2, Molecular features