Abstract: Breast cancer is a highly heterogeneous malignant tumor whose progression is closely associated with the dynamic regulation of immune cells within the tumor microenvironment（TME）. Mast cells（MCs），as key immune cells with functional plasticity in the TME，display dual roles in either promoting or suppressing tumor growth，which are co-regulated by their spatial localization and the specific breast cancer subtype. This article provides a systematic review of the recruitment mechanisms of MCs，as well as their pro-tumorigenic and anti-tumor functions in breast cancer，with a particular emphasis on elucidating the functional heterogeneity of MCs across Luminal，HER2-positive，and triple-negative breast cancer（TNBC） subtypes. This study demonstrate that the dual functions of MCs are collectively determined by subpopulation heterogeneity，microenvironmental signals，and breast cancer subtype specificity. Notably，antigen-presenting MCs（apMCs） play a central role in immune sensitization in TNBC. This study offers a theoretical foundation for targeting specific MC subpopulations to inhibit pro-tumor pathways or enhance antigen presentation，thereby reversing drug resistance and improving combination immunotherapy strategies.

Key words: Breast cancer, Mast cells, Tumor microenvironment, Molecular subtypes, Review

摘要： 乳腺癌作为高度异质性的恶性肿瘤，其发展与肿瘤微环境（TME）中免疫细胞的动态调控密切相关。肥大细胞（MCs）作为 TME 中具有功能可塑性的关键免疫细胞，其功能受空间定位和乳腺癌亚型共同调控，呈现促瘤与抑瘤的双重作用。本文系统综述了 MCs 在乳腺癌中的募集机制、促瘤作用及抑瘤作用。重点剖析 MCs 功能在Luminal、HER2 过表达及三阴性乳腺癌（TNBC）亚型中的异质性。本文表明 MCs 的双重角色由其亚群异质性、微环境信号及乳腺癌亚型特异性共同决定，其中抗原提呈型 MCs（apMCs）在 TNBC 免疫增敏中具有核心作用。本研究为靶向 MCs 调控特定亚群、阻断促瘤通路或增强抗原呈递功能，逆转耐药及优化免疫联合治疗提供了理论依据。

关键词: 乳腺癌, 肥大细胞, 肿瘤微环境, 分子亚型, 综述