Improving treatment of Hodgkin Lymphoma with molecular risk classification and highly sensitive residual disease monitoring by circulating cell-free DNA sequencing

霍奇金淋巴瘤(HL)是一种源于B细胞的血液系统恶性肿瘤。HL的一个显著特征是致病的、恶性的霍奇金细胞和里德-斯特恩伯格(Reed-Sternberg，HRS)细胞仅占肿瘤组织的1-10%，其余的细胞由支持肿瘤生长的复杂微环境组成。肿瘤活检中HRS细胞的缺乏使得用传统方法难以理解HL的遗传驱动因素。两个挑战定义了当前HL的医学需求。首先，侵袭性、多药剂化疗会导致严重的早期和晚期毒副作用。其次，在大约20%-30%的患者中，第一次治疗尝试不成功，患者最终复发并经常死亡。目前，治疗分层纯粹是基于临床风险因素；目前缺乏基于是否存在遗传特征的分子风险分类。因此，为了改善治疗结果，减少早期和晚期毒性，我们需要确定HL的分子定义亚群并个体化治疗。癌症患者循环中的游离DNA从凋亡细胞中释放出来，并含有反映肿瘤遗传学的循环肿瘤衍生DNA(CtDNA)。在两个独立的项目中，我们能够成功地使用ctDNA来检测HL中肿瘤相关的突变和拷贝数变化。其中一个项目是DFG以前的项目，我们计划在此应用程序中扩展该项目。在本项目中，我们使用ctDNA对166例HLS进行了全外显子组测序。另一个项目是我们团队的一个独立项目，在这个项目中，我们开发了一个基于靶向ctDNA测序板的HL基因分型平台。在这项研究中，我们还开发了一种在治疗期间和治疗后的随访样本中检测HL患者微小残留病(MRD)的方法。介绍该项目成果的手稿已作为预印本出版(Sobesky等人，MedRxiv 2021年)，目前正在审查中。我们这一扩展的主要目标是开发一种分子风险分类来改善HL的预测。此外，我们将通过一个动态风险模型来扩展这一点，该模型包括使用我们开发的MRD试验进行治疗的早期分子反应的深度。具体来说，我们将致力于以下目标：(1)我们将确定液体活检可检测到的与新诊断的HL预后有利或不利相关的分子特征，(2)我们将在复发和难治性HL的单独队列中验证这一特征，以及(3)我们将通过动态风险描述(包括早期最小残留疾病评估)来完善这些反应特征。总之，扩展项目可能提供HL的分子风险分类，同时探索HL治疗过程中的动态风险建模，作为HL治疗中潜在的未来范式转变。

Hodgkin lymphoma (HL) is a B cell-derived, hematological malignancy. A remarkable feature of HL is that the pathognomonic, malignant Hodgkin and Reed-Sternberg (HRS) cells make up only 1-10% of the tumor tissue while the rest is composed of a complex microenvironment supporting tumor growth. This paucity of HRS cells in the tumor biopsy has made understanding the genetic drivers of HL with traditional approaches difficult.Two challenges define the current medical need in HL. First, aggressive, multi-agent chemotherapy treatment leads to severe early and late toxicities. Second, in about 20-30% of patients the first treatment attempt is not successful and the patients ultimately relapse and often die. Currently, treatment stratification is based purely on clinical risk factors; a molecular risk classification based on presence or absence of genetic features is currently lacking. Thus, to improve treatment outcome and reduce both early and late toxicities, we need to identify molecularly defined subgroups of HL and individualize treatment.Cell-free DNA in the circulation of cancer patients is released from apoptotic cells and contains circulating tumor-derived DNA (ctDNA) in cancer patients reflecting the genetics of the tumor.In two separate projects, we were able to show that ctDNA can be successfully used to detect tumor-associated mutations and copy number alterations in HL. One of these projects is the DFG previous project that we plan to extend with this application. In this project we performed whole-exome sequencing using ctDNA in 166 HLs. The other project is an independent project of our group in which we developed a platform to genotype HL based on a targeted ctDNA sequencing panel. In this study we also developed an approach to detect minimal residual disease (MRD) in HL patients in follow-up samples during and after treatment. A manuscript presenting the results of this project is published as a preprint (Sobesky et al., medRxiv 2021) and currently under review. Our overarching aim for this extension is to develop a molecular risk classification to improve prognostication in HL. Furthermore, we will expand on this with a dynamic risk model including depth of early molecular response to treatment using the MRD assay developed by us. In detail, the following aims will be addressed: (1) We will identify molecular signatures detectable by liquid biopsy that are associated with a favorable or adverse prognosis in newly diagnosed HL, (2) we will validate this signature in a separate cohort of relapsed and refractory HL and (3) we will refine these response signatures by dynamic risk profiling including early minimal residual disease assessment.Altogether, the extension project is likely to deliver a molecular risk classification of HL while at the same time exploring dynamic risk modelling during HL treatment as a potential future paradigm shift in HL treatment.