目的：探讨内吞作用相关基因FCHO2在各亚型乳腺癌中的表达及其与乳腺癌患者的预后和免疫细胞浸润的相关性。方法：应用免疫组化法和bc-GenExMiner v5.0数据库数据分析FCHO2在各亚型乳腺癌组织中的表达，通过GEO和TIMER数据库数据分析FCHO2与各亚型乳腺癌患者预后和免疫细胞浸润的关系，利用STRING和GEPIA数据库数据分析与FCHO2的互作蛋白网络和其与互作蛋白的相关性，通过UALCAN和DAVID数据库数据对乳腺癌组织中FCHO2表达相关基因进行KEGG和GO分析。结果：免疫组化法结果显示，FCHO2在管腔型和HER2+乳腺癌组织中均呈高表达（均P<0.05），且与HER2和Ki67表达有关联（P=0.03和P=0.007）。FCHO2高表达的管腔型乳腺癌患者总生存期（OS）和无复发生存期（RFS）均明显缩短（均P<0.05）。FCHO2蛋白与EPS15等多种蛋白表达相关且构成蛋白-蛋白互作网络。KEGG和GO分析显示，乳腺癌组织中FCHO2相关表达基因主要与昼夜节律、自噬等生物学过程有关，涉及叉头框蛋白O（FoxO）和TGF-β等信号通路。FCHO2表达与各亚型乳腺癌组织中的免疫细胞浸润相关（均P<0.05）。结论：FCHO2在管腔型、HER2+乳腺癌组织中呈高表达，且与管腔型乳腺癌患者预后及免疫细胞浸润相关，其可能成为乳腺癌治疗的潜在靶点。

Objective: To explore the expression of endocytosis-related gene FCHO2 in different subtypes of breast cancer, and its relationship with the prognosis and immune cell infiltration of breast cancer patients. Methods: Immunohistochemical staining and bc-GenExMiner v5.0 database were used to analyze the expression of FCHO2 in different subtypes of breast cancer. The relationship between FCHO2 and the prognosis and immune cell infiltration of different subtypes of breast cancer patients was analyzed using GEO and TIMER database. The protein-protein interaction network of FCHO2 and its correlation with the interacting proteins were analyzed using STRING database and GEPIA database, respectively. KEGG and GO analysis of FCHO2-related genes in breast cancer tissues were performed using UALCAN and DAVID databases. Results： Immunohistochemical staining showed that FCHO2 in luminal and HER2+ breast cancer tissues were highly expressed (both P<0.05), and correlated with the expressions of HER2 and Ki67 (P=0.03 or P=0.007). Both the OS and RFS of luminal breast cancer patients with high expression of FCHO2 were significantly decreased (both P<0.05). FCHO2 protein was related to the expressions of many proteins such as EPS15 and constituted the protein-protein interaction network. KEGG and GO analysis indicated that the expression of FCHO2-related genes in breast cancer tissues were mainly related to biological processes such as circadian rhythm and autophagy, and involved FoxO and TGF-β signaling pathways. The expression of FCHO2 was correlated with immune cell infiltration in tissues of different subtypes of breast cancer. Conclusion: FCHO2 is highly expressed in luminal and HER2+ breast cancer tissues, and is correlated with the patient prognosis and immune cell infiltration of luminal breast cancer. FCHO2 may become a potential target for breast cancer treatment.

国家自然科学基金（No. 82303048）；山西省基础研究计划（No. 20210302124185）；山 西 省 科 技 创 新人才团队（青年）项目 （No. 202204051001024）