Molecular pathogenesis of nodular lymphocyte predominant Hodgkin lymphoma and related neoplasias

结节性淋巴细胞为主型霍奇金淋巴瘤（NLPHL）与经典型霍奇金淋巴瘤（cHL）相比，具有B细胞表型保留、男性多见、临床表现惰性等特点。在目前的资助期间，我们能够通过对NLPHL-DLBCL复合淋巴瘤的弥漫性大细胞淋巴瘤（DLBCL）组分进行全基因组测序，在NLPHL中鉴定出三种新的复发突变基因SGK 1、DUSP 2和JUNB。此外，通过基因表达谱研究了从NLPHL转化的更大系列的DLBCL，其揭示了具有PD-L1表达的显著宿主抗淋巴瘤反应和几种情况下肿瘤细胞中MYC的下调。富含T细胞/组织细胞的大B细胞淋巴瘤（THRLBCL）和THRLBCL样NLPHL通常难以描述。我们在这里研究了新血管形成的模式，这进一步支持了两种淋巴瘤类型之间的密切关系。另一个诊断挑战是鉴别进行性转化的生发中心（PTGC）和NLPHL早期累及淋巴结。我们描述了PTGC的五种典型模式，便于病理学家区分非肿瘤性PTGC和早期NLPHL。鉴于小男孩可能受到NLPHL的影响，通常是IgD阳性，我们假设儿科NLPHL可能是由儿童中经常观察到的传染病引发的。重组Fab B片段来自B细胞受体序列的主要LP细胞进行了测试，对细菌裂解物，事实上，几个案件显示对卡他莫拉氏菌裂解物的反应性。在新的资助期内，我们的目标是进一步确定突变的基因，有助于NLPHL的发病机制。因此，我们计划对从原代NLPHL获得的3000个显微切割的LP细胞的整个外显子组进行测序，而不进行转化。此外，我们希望进一步阐明基于突变基因的NLPHL和THRLBCL的关系。在NLPHL中经常突变的候选基因将应用定制的富集方法在THRLBCL病例的子集中筛选突变。此外，我们还旨在阐明持续的免疫应答和T细胞库在NLPHL肿瘤维持中的作用。因此，T细胞在M.将对卡他相关的NLPHL病例进行显微解剖，并对T细胞受体γ基因进行PCR扩增和测序。如果我们的假设是正确的，即NLPHL肿瘤需要持续的T细胞应答，我们将期望找到寡克隆T细胞群。此外，目前还不清楚为什么NLPHL可以显示不同的生长模式与预后的影响。将检测特定组织病理学生长模式的发生是否与某些HLA亚型相关。最后，我们计划研究可能在NLPHL中鉴定的新突变基因的功能作用。

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) displays a variety of differences to classical Hodgkin lymphoma (cHL), which consist of a preserved B cell phenotype, a strong male predominance and an indolent clinical behavior. In the present funding period we were able to identify three novel recurrently mutated genes, SGK1, DUSP2 and JUNB in NLPHL, by whole genome sequencing of the diffuse large cell lymphoma (DLBCL) component of NLPHL-DLBCL composite lymphomas. Furthermore, a larger series of DLBCL transformed from NLPHL was investigated by gene expression profiling which revealed a prominent host anti-lymphoma reaction with PD-L1 expression and a downregulation of MYC in the tumor cells of several cases. T cell/histiocyte rich large B cell lymphoma (THRLBCL) and THRLBCL-like NLPHL are often difficult to delineate. We studied here the patterns of neovascularization which furthermore support the strong relationship between both lymphoma types. Another diagnostic challenge is the differentiation between progressively transformed germinal centers (PTGC) and early involvement of the lymph node by NLPHL. We described five typical patterns of PTGC, which facilitate pathologists to differentiate between non-neoplastic PTGC and early NLPHL. Given that young boys can be affected by NLPHL, which is often IgD-positive, we had the hypothesis that pediatric NLPHL could be triggered by an infectious disease which is frequently observed in children. Recombinant Fab fragments derived from the B cell receptor sequences of primary LP cells were tested against bacterial lysates, and indeed, several cases showed reactivity against lysates of Moraxella catarrhalis.In the new funding period, we aim to identify further mutated genes which contribute to the pathogenesis of NLPHL. Therefore we plan to sequence the whole exome from 3000 microdissected LP cells obtained from primary NLPHL without transformation. Additionally, we want to further elucidate the relationship of NLPHL and THRLBCL based on mutated genes. Candidate genes, which are frequently mutated in NLPHL will be screened for mutations in a subset of THRLBCL cases applying a custom made enrichment approach. Moreover, we also aim to clarify the role of an ongoing immune response and the T cell repertoire in the maintenance of the NLPHL tumor. For this reason, T cells rosetting around LP cells of M. catarrhalis-associated NLPHL cases, will be microdissected and the T cell receptor gamma genes will be PCR amplified and sequenced. If our hypothesis is correct that the NLPHL tumor needs an ongoing T cell response, we would expect to find oligoclonal T cell populations. Furthermore, it is unclear, why NLPHL can show different growth patterns with prognostic implications. It will be tested if the occurrence of particular histopathologic growth patterns is associated with certain HLA subtypes. Last, we plan to study the functional role of the novel mutated genes that could be identified in NLPHL.