Background: Tumour mutational burden (TMB) is an emerging biomarker for predicting the efficacy of immune checkpoint inhibitors (ICIs) in cancer therapy. While its role is well established in lung cancer and melanoma, its predictive value for breast and prostate cancers remains unclear. Objective: This systematic review aimed to assess the predictive value of TMB for ICI therapy across four major cancer types—lung, melanoma, breast, and prostate—and to explore factors contributing to the variability in its effectiveness as a biomarker. Methods: A systematic search and a review of the literature were conducted in accordance with PRISMA guidelines. Studies examining the relationship between TMB levels and clinical outcomes following ICI therapy in the specified cancers were analyzed. The data were synthesized to evaluate TMB’s predictive value and identify gaps in the current research. Results: High TMB consistently correlated with improved outcomes in lung cancer and melanoma, confirming its predictive utility in these cancers. Conversely, the findings for breast and prostate cancers were inconclusive. The variability in TMB’s predictive value for these cancers suggests the need for complementary biomarkers or refined criteria to enhance its reliability. Methodological inconsistencies in TMB evaluation were also noted as a significant limitation. Conclusions: TMB serves as a robust biomarker for predicting ICI response in lung cancer and melanoma, but demonstrates limited predictive utility in breast and prostate cancers. Future research should prioritize standardizing TMB assessment protocols and investigating additional biomarkers to improve treatment personalization for these cancer types.
背景：肿瘤突变负荷（TMB）是一种新兴的生物标志物，用于预测免疫检查点抑制剂（ICIs）在癌症治疗中的疗效。尽管其在肺癌和黑色素瘤中的作用已得到广泛认可，但其对乳腺癌和前列腺癌的预测价值仍不明确。目的：本系统综述旨在评估TMB在肺癌、黑色素瘤、乳腺癌和前列腺癌这四种主要癌症类型中对ICI治疗的预测价值，并探讨影响其作为生物标志物有效性差异的因素。方法：根据PRISMA指南进行了系统文献检索与综述，分析了在特定癌症中探讨TMB水平与ICI治疗后临床结局关系的研究。通过数据整合评估TMB的预测价值，并指出当前研究中的不足。结果：高TMB与肺癌和黑色素瘤的改善结局持续相关，证实了其在这两类癌症中的预测效用。相反，对于乳腺癌和前列腺癌，研究结果尚无定论。TMB在这些癌症中预测价值的差异性表明，需要补充生物标志物或完善评估标准以增强其可靠性。此外，TMB评估方法的不一致性也被认为是重要的局限性。结论：TMB是预测肺癌和黑色素瘤对ICI反应的可靠生物标志物，但在乳腺癌和前列腺癌中的预测效用有限。未来研究应优先推进TMB评估方案的标准化，并探索其他生物标志物，以提升这些癌症类型的治疗个体化水平。
肿瘤(癌症)患者之家