目的：探讨中国胃癌的病理分型特点。方法：选取2019年1月至2022年7月在上海交通大学医学院附属瑞金医院进行连续手术的3 071例胃癌病例，根据2019年第5版世界卫生组织（World Health Organization，WHO）消化系统肿瘤新分类中的胃癌分型，分析其临床和病理特点。结果：3 071例胃癌患者中有3 003例患者经病理诊断为胃腺癌（97.79%）。胃腺癌的男女发病比为2.18:1，患者中位年龄为64岁。本研究中，管状腺癌、乳头状腺癌、混合型腺癌、低黏附性癌和黏液腺癌是常见的组织学亚型，这5种组织学亚型占所有胃腺癌的构成比为99.03%。982例胃癌标本进行了Lauren分型的患者中，肠型腺癌相对多见，构成比为46.03%，与弥漫型腺癌病例数之比为1.39:1。在3 003例胃腺癌病例中，有172例（5.73%）存在错配修复蛋白表达缺失（mismatch repair deficiency, dMMR），而其中163例（94.77%）为MLH1/PMS2型缺失。3 003例胃腺癌患者中，EB病毒编码小RNA（Epstein-Barr encoded RNA，EBER）阳性率为1.40%（42/3 003）。3 003例胃腺癌样本中，661例人表皮生长因子受体2（human epidermal growth factor receptor-2, HER2）蛋白表达结果为1+，而2+及3+的例数分别为229例和113例。结论：中国人胃癌病理亚型分布有其独特特征，肠型腺癌与弥漫型腺癌的比率低于亚洲平均水平；EB病毒阳性型胃癌占比低于国内外平均水平；HER2免疫组化检测结果为2+及以上病例数所占比例也低于国外报道。

Objective: To retrospectively analyze the clinicopathological data of gastric cancer (GC) in order to investigate the histological classification and epidemiological characteristics of GC in China. Methods: A total of 3 071 cases of malignant gastric epithelial tumors who underwent surgery in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from January 2019 to July 2022 were included. The relevant pathological and clinical data were summarized and analyzed according to the 5th Edition of WHO classification of digestive system tumors and literatures was reviewed. Results: Among 3 071 cases of GC, 3 003 were diagnosed as having adenocarcinoma. The male to female incidence ratio was 2.18:1, with a median age of 64 years. It showed tubular adenocarcinoma, papillary adenocarcinoma, mixed adenocarcinoma, poorly cohesive carcinoma and mucinous adenocarcinoma are the most common. In this study, these 5 histological subtypes accounted for 96.84% of all gastric adenocarcinomas. For Lauren classification, ratio of intestinal type to diffuse type was 1.39:1. MMR deficiency was found in 5.73% of gastric adenocarcinoma cases, among which 163 cases were with loss of MLH1 and PMS2 expression. It revealed that 1.40% of the cases were positive for Epstein-Barr virus encoded small RNA (EBER). In the human epidermal growth factor receptor-2 (HER2) testing by immunohistochemistry (IHC) for adenocarcinoma, the cases of protein expression for IHC score 2+ and 3+ were 229 and 113. Conclusions: The pathological subtype distribution of gastric cancer in China has its unique characteristics, with a ratio of intestinal adenocarcinoma to diffuse adenocarcinoma lower than average level in Asian. The proportion of Epstein-Barr virus (EBV) positive gastric cancer is lower than the average level at abroad, while the proportions of cases with HER2 IHC score 2+ or 3+ are also lower than foreign reports.