本研究旨在评估妇科癌肉瘤中间皮素（MSLN）的表达，并确定其临床意义以及与人表皮生长因子受体2（HER2）表达的相关性。我们回顾性评估了接受过手术治疗的子宫癌肉瘤（UCS）和卵巢癌肉瘤（OCS）患者。 1997 年至 2019 年间进行了手术。还对福尔马林固定、石蜡包埋的 MSLN（克隆 SP74）和 HER2（克隆 4A5）标本进行了免疫组织化学染色。 MSLN 使用 H 分数和 4 级评分系统 (0-3) 进行评分。 MSLN 阳性定义为任何强度的任何阳性细胞，而高 MSLN 表达定义为 ≥30% 的肿瘤细胞中强度≥2。根据修订的2018年美国临床肿瘤学会/美国病理学家学院标准对HER2表达进行评分。总共招募了128名患者，其中119名UCS患者和9名OCS患者。 UCS 中的所有病例均表现出 MSLN 阳性，其中 33.9% 表现出高 MSLN 表达。临床病理学特征与 MSLN 高或低表达没有显着相关性。然而，高 MSLN 组的总生存期 (OS) 比低 MSLN 组更长（未评估 vs. 36.8 个月；风险比 = 0.48，95% 置信区间 = 0.26-0.89，p = 0.016）。 HER2 高患者的 MSLN 表达高于 HER2 阴性患者。在高 MSLN 和低 MSLN 表达组中，HER2 状态不影响 OS。 OCS显示100% MSLN阳性，其中66.6%高MSLN。MSLN表达在妇科癌肉瘤中广泛观察到。此外，高 MSLN 表达是 UCS 的有利预后因素。即使在抗 HER2 治疗时代，MSLN 也可能成为 UCS 的一个有前途的治疗靶点。© 2024。亚洲妇科肿瘤学会、韩国妇科肿瘤学会和日本妇科肿瘤学会。

This study aimed to evaluate mesothelin (MSLN) expression and determine its clinical significance and correlation with human epidermal growth factor receptor 2 (HER2) expression in gynecological carcinosarcoma.We retrospectively evaluated patients with uterine carcinosarcoma (UCS) and ovarian carcinosarcoma (OCS) who underwent surgery between 1997 and 2019. Immunohistochemical staining of formalin-fixed, paraffin-embedded specimens for MSLN (clone SP74) and HER2 (clone 4A5) was also performed. MSLN was scored using the H-score and 4-tired scoring system (0-3+). MSLN positivity was defined as any positive cell at any intensity, while high MSLN expression was defined as an intensity of ≥2+ in ≥30% of tumor cells. HER2 expression was scored according to modified 2018 American Society of Clinical Oncology/College of American Pathologists criteria.A total of 128 patients were recruited, including 119 with UCS and 9 with OCS. All cases in UCS exhibited MSLN positivity, and 33.9% showed high-MSLN expression. Clinicopathological characteristics were not significantly associated with high or low-MSLN expression. However, the high-MSLN group showed more prolonged overall survival (OS) than the low-MSLN group (not assessed vs. 36.8 months; hazard ratio=0.48, 95% confidence interval=0.26-0.89, p=0.016). HER2-high patients had higher MSLN expression than HER2-negative patients. In high-MSLN and low-MSLN expression groups, HER2 status did not affect OS. OCS showed 100% MSLN positivity, with 66.6% high-MSLN.MSLN expression is widely observed in gynecological carcinosarcomas. Moreover, high-MSLN expression is a favorable prognostic factor for UCS. MSLN could be a promising therapeutic target for UCS, even in the era of anti-HER2 therapy.© 2024. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology, and Japan Society of Gynecologic Oncology.