摘要目的:探讨SMARCA4（是SWI/SNF染色质重塑复合物中的核心催化亚基）蛋白表达缺失性子宫内膜去分化癌/未分化癌（DDEC/UDEC）的临床病理特征。方法:收集2019年1月至2023年12月在福建省肿瘤医院确诊的DDEC/UDEC患者共48例，其中SMARCA4蛋白表达缺失性DDEC/UDEC患者10例，分析其临床和病理特征（形态学、免疫表型）、分子分型及预后。结果:（1）临床特征：10例SMARCA4蛋白表达缺失性DDEC/UDEC患者的中位年龄为56岁（范围：48~65岁），国际妇产科联盟（FIGO）分期Ⅰ~Ⅱ期和Ⅲ~Ⅳ期各5例。（2）病理特征：肿瘤细胞黏附性差，常见脉管内癌栓（8/10），部分可见泡状核细胞（6/10）、横纹肌样细胞（4/10）及组织细胞吞噬凋亡小体或碎片形成的星空现象（4/10）；6例（6/10）错配修复（MMR）蛋白表达缺失，2例（2/10）p53蛋白突变型表达，5例（5/10）细胞程序性死亡配体1（PD-L1）阳性表达。（3）分子分型：10例患者中，POLE突变（POLEmut）型1例（1/10），错配修复缺陷（MMR-d）型5例（5/10），p53异常型1例（1/10），无特异性分子改变（NSMP）型3例（3/10）。（4）预后：10例患者的中位随访时间20个月（范围：7~42个月），随访期内5例（5/10）因肿瘤进展、多发转移死亡，其余5例（5/10）术后定期复查，未见复发征象。2年无进展生存率和总生存率分别为58.3%和52.5%。结论:SMARCA4蛋白表达缺失见于约1/5的DDEC/UDEC患者，具有较高的侵袭性，预后较差。SMARCA4蛋白表达缺失性DDEC/UDEC患者中，约半数存在MMR蛋白表达缺失和PD-L1蛋白阳性表达，提示其可能会从免疫检查点抑制剂治疗中获益。

abstractsObjective:To investigate the clinicopathological characteristics of dedifferentiated endometrial carcinoma/undifferentiated endometrial carcinoma (DDEC/UDEC) with loss of expression of SMARCA4.Methods:A total of 10 cases with loss of expression of SMARCA4 were diagnosed at Fujian Cancer Hospital between January 2019 and December 2023. A retrospective analysis was conducted on the clinical characteristics, morphology, immunophenotype, molecular classification, and prognosis.Results:(1) Clinical characteristics: among 10 cases of DDEC/UDEC with loss of expression of SMARCA4, the patients′ age ranged from 48 to 65 years, with a median age of 56 years.Five cases were classified as International Federation of Gynecology and Obstetrics (FIGO) stages Ⅰ-Ⅱ, while the remaining five were categorized as stages Ⅲ-Ⅳ. (2) Pathological features: tumor cells exhibited poor cell adhesion, with common intravascular tumor emboli (8/10), occasional vacuolated nuclei (6/10), rhabdoid cells (4/10), and starry sky phenomenon formed by tissue cell phagocytosis apoptosis bodies or fragments (4/10). Six cases (6/10) showed loss of mismatch repair (MMR) protein expression, two cases (2/10) exhibited p53 mutant expression, and five cases (5/10) tested positive for programmed cell death ligand 1 (PD-L1). (3) Molecular subtyping: molecular subtyping revealed POLEmut in 1 case (1/10), mismatch repair deficient (MMR-d) in 5 cases (5/10), p53 abn in 1 case (1/10), and no specific molecular profile (NSMP) in 3 cases (3/10). (4) Prognosis: the follow-up period ranged from 7 to 42 months, with a median of 20 months. Five patients succumbed to the tumor, whereas the remaining five exhibited no recurrence during subsequent postoperative evaluations. The 2-year progression-free survival rates and overall survival rates were 58.3% and 52.5%, respectively.Conclusions:Loss of expression of SMARCA4 occurs in approximately 1/5 of DDEC/UDEC, which presents with an aggressive clinical course and a poor prognosis. About half of them show MMR protein loss expression and PD-L1 positive expression, suggesting that there might be benefit from treatment with immune checkpoint inhibitors.