雌激素受体阳性（ER）乳腺癌占所有乳腺癌的三分之二，其早期和晚期复发仍然威胁着患者的长期生存和生活质量。寻找候选肿瘤抗原和潜在的治疗靶点对于解决这些未满足的需求至关重要。采用相对和绝对定量（iTRAQ）蛋白质组分析的同量异位标签来识别ER 乳腺癌和相应的邻近正常组织之间的差异表达蛋白（DEP）。通过生物信息学分析筛选候选DEP，并通过免疫组织化学（IHC）染色和蛋白质印迹证实其表达。进行了一系列体外实验，包括伤口愈合测定、集落形成和细胞周期测定，以揭示所选 DEP 的功能。并进一步分析其临床意义。共发现369个DEP（倍数变化 ≥ 2.0或≤ 0.66，P < 0.05）。与正常组织相比，ER 乳腺癌中有358个蛋白上调，11个蛋白下调。 GO和KEGG富集分析表明DEPs与RNA调控和代谢途径密切相关。 STRING分析发现ESF1和MIPEP是乳腺癌的核心基因，IHC染色和蛋白质印迹证实了其表达增加。敲除 ESF1 和 MIPEP 可抑制集落形成并增加细胞凋亡。此外，敲低 ESF1 会抑制伤口愈合，但不会抑制 MIPEP。此外，ESF1和MIPEP表达与患者预后呈负相关。ESF1和MIPEP的上调促进ER  乳腺癌增殖，这可能为新疗法的开发提供新靶标。© 2024。作者。

Estrogen receptor-positive (ER+) breast cancer accounts for two-thirds of all breast cancers, and its early and late recurrences still threaten patients' long-term survival and quality of life. Finding candidate tumor antigens and potential therapeutic targets is critical to addressing these unmet needs.The isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was employed to identify the differentially expressed proteins (DEPs) between ER + breast cancer and corresponding adjacent normal tissue. Candidate DEPs were screened by bioinformatic analyses, and their expression was confirmed by immunohistochemical (IHC) staining and western blot. A series of in vitro experiments, including wound healing assay, colony formation, and cell cycle assay, were performed to reveal the functions of selected DEPs. Additionally, their clinical significances were further analyzed.A total of 369 DEPs (fold change ≥ 2.0 or ≤ 0.66, P < 0.05) were discovered. Compared with normal tissue, 358 proteins were up-regulated and 11 proteins were down-regulated in ER + breast cancer. GO and KEGG enrichment analysis showed that DEPs were closely associated with RNA regulation and metabolic pathways. STRING analysis found ESF1 and MIPEP were the hub genes in breast cancer, whose increased expressions were verified by the IHC staining and western blot. Knocking down ESF1 and MIPEP inhibited colony formation and increased cell apoptosis. Besides, knocking down ESF1 inhibited wound healing but not MIPEP. In addition, ESF1 and MIPEP expression were negatively associated with patient prognosis.The upregulation of ESF1 and MIPEP promoted ER + breast cancer proliferation, which might provide novel targets for the development of new therapies.© 2024. The Author(s).