Treatment of cancer has transformed with the introduction of checkpoint inhibitors. However, the majority of solid tumor patients do not respond to checkpoint blockade. In contrast, the response rate to programmed cell death 1 (PD-1) blockade in relapsed/refractory classical Hodgkin lymphoma (cHL) is 65% to 84% which is the highest among all cancers. Currently, checkpoint inhibitors are only approved for cHL and primary mediastinal B-cell lymphoma as the responses to single-agent checkpoint blockade in other hematologic malignancies is disappointingly low. Various established biomarkers such as programmed cell death 1 ligand 1 (PD-L1) protein surface expression, mismatch repair (MMR) status, and tumor mutational burden (TMB) are routinely used in clinical decision-making in solid tumors. In this review, we will explore these biomarkers in the context of hematologic malignancies. We review characteristic 9p24.1 structural alteration in cHL and primary mediastinal B-cell lymphoma (PMBCL) as a basis for response to PD-1 inhibition, as well as the role of antigen presentation pathways. We also explore the reported frequencies of MMR deficiency in various hematologic malignancies and investigate TMB as a predictive marker.

癌症的治疗已经通过引入检查点抑制剂而发生了变化。但是，大多数实体瘤患者对检查站封锁没有反应。相比之下，复发/难治性经典霍奇金淋巴瘤（cHL）对程序性细胞死亡1（PD-1）阻滞的反应率是65％至84％，在所有癌症中最高。目前，检查点抑制剂仅获批准用于cHL和原发性纵隔B细胞淋巴瘤，因为其他血液系统恶性肿瘤中对单药检查点阻断的反应低得令人失望。在实体瘤的临床决策中通常使用各种已建立的生物标记物，例如程序性细胞死亡1配体1（PD-L1）蛋白表面表达，错配修复（MMR）状态和肿瘤突变负担（TMB）。在这篇评论中 我们将在血液系统恶性肿瘤的背景下探索这些生物标志物。我们审查特征性9p24.1结构改变在cHL和原发性纵隔B细胞淋巴瘤（PMBCL）作为对PD-1抑制反应以及抗原呈递途径的作用的基础。我们还探讨了各种血液恶性肿瘤中MMR缺乏症的报道频率，并调查了TMB作为预测指标。