精子相关抗原5（SPAG5）是一种有丝分裂纺锤蛋白，调控姐妹染色单体在子细胞中的分离。最近的研究发现它在各种癌症中过表达，表明其具有致癌特性和功能。然而，关于SPAG5在不同癌症类型中的诊断、预后和免疫相关效应的全面分析仍然缺乏。本研究使用生物信息学方法并整合多个公共数据库，探索SPAG5的潜在致癌作用。我们分析了其表达、预后、相关化学物质、富集通路、免疫浸润以及其对不同肿瘤遗传改变的影响。结果显示，SPAG5在大多数癌症中高度表达，并与患者预后差异显著相关。此外，SPAG5的表达在15种不同癌症类型中显示了早期癌症诊断的潜力。在肿瘤免疫方面，SPAG5的高表达与免疫抑制型肿瘤微环境和免疫治疗疗效指标相关。SPAG5的表达与大多数免疫细胞浸润呈负相关，但与Th2细胞和MDSC细胞呈显著正相关。多色荧光免疫组化数据表明，SPAG5激活了肿瘤内的免疫细胞群体，表明其在肿瘤微环境中具有重要作用。富集分析显示，SPAG5相关基因主要参与细胞周期、细胞衰老、P53信号通路和FoxO信号通路。此外，我们证实了SPAG5在癌细胞中的高表达，并观察到其沉默使p53蛋白的表达上调。综上所述，SPAG5在各种癌症中具备诊断、预后和免疫标志物的价值，可能为肿瘤免疫治疗提供新的靶点。© 2023美国实验生物学会。

Sperm-associated antigen 5 (SPAG5) is a mitotic spindle protein that regulates the separation of sister chromatids into daughter cells. Recent studies have discovered its overexpression in various cancers, suggesting its oncogenic characteristics and functions. However, a comprehensive analysis of SPAG5 regarding its diagnostic, prognostic, and immune-related effects across different cancer types is lacking. In this study, we employed bioinformatics methods and integrated multiple public databases to explore the potential oncogenic role of SPAG5. We analyzed its expression, prognosis, related chemicals, enriched pathways, immune infiltration, and its impact on different tumor genetic alterations. The results revealed that SPAG5 is highly expressed in most cancers and significantly correlates with poor patient prognosis. Additionally, SPAG5 expression showed potential for early cancer diagnosis in 15 different cancer types. In terms of tumor immunity, high expression of SPAG5 was associated with an immunosuppressive tumor microenvironment and immune therapy efficacy indicators. SPAG5 expression exhibited a negative correlation with most immune cell infiltrates but demonstrated a significant positive correlation with Th2 cells and MDSC cells. Multicolor fluorescence immunohistochemistry demonstrated that SPAG5 activates immune cell populations within tumors, indicating its significant role in the tumor microenvironment. Enrichment analysis indicated that SPAG5-related genes are mainly involved in cell cycle, cellular senescence, P53 signaling pathway, and FoxO signaling pathway. Furthermore, we confirmed the high expression of SPAG5 in cancer cells and observed that its knockdown upregulated the expression of the p53 protein. In conclusion, SPAG5 holds value as a diagnostic, prognostic, and immune biomarker in various cancers and may provide a novel target for tumor immunotherapy.© 2023 Federation of American Societies for Experimental Biology.