Molecular signatures for Hairy cell leukemia

Analysis of the expression profile of 298 mRNA's, measured with the nCounter (Nanostring Technologies platform), in 13 samples from the peripheral blood of Hairy cell leukemia patients Hairy cell leukemia (HCL) is a rare chronic B-cell malignancy, characterized by infiltration of bone marrow, blood and spleen by typical “hairy cells” that bear the BRAFV600E mutation. However, in addition to the intrinsic activation of the MAP kinase pathway as a consequence of the BRAFV600E mutation, the potential participation of other signaling pathways to the pathophysiology of the disease remains unclear. Using mRNA gene expression profiling based on the Nanostring technology and the analysis of 290 genes with crucial roles in B-cell lymphomas, we defined a 17 gene expression signature specific for HCL. Our analysis revealed intrinsic activation of the non-canonical NF-B pathway with underexpression of BIRC2 and BIRC3, two specific non-canonical NF-B inhibitors. Western blots confirmed activation of this pathway with increased processing of p100 in primary HCL samples. Separate analysis of samples from classical and variant forms of hairy cell leukemia showed almost similar mRNA expression profiles apart from overexpression in vHCL of the immune checkpoints CD274 and PDCD1LG2 and underexpression of FAS. Our results provide a better understanding of the pathogenesis of HCL and describe new and potential targets for treatment approaches and guidance for studies in the molecular mechanisms of HCL. 24 samples from peripheral blood: 13 CLL samples (11 cHCL, 2 vCHL); 8 samples from normal blood donors; 3 samples from purified B lymphocytes本研究采用nCounter（Nanostring Technologies平台）技术，对298条信使核糖核酸（mRNA）的表达谱进行检测，分析了13例毛细胞白血病（Hairy cell leukemia, HCL）患者的外周血样本。毛细胞白血病是一种罕见的慢性B细胞恶性肿瘤，其特征为典型的“毛细胞”浸润骨髓、血液与脾脏，此类毛细胞携带BRAFV600E突变。然而，除BRAFV600E突变引发的丝裂原活化蛋白激酶（MAP kinase）通路固有激活外，其他信号通路在该病病理生理过程中的潜在参与机制仍不明确。本研究基于Nanostring技术开展mRNA基因表达谱分析，并对B细胞淋巴瘤中具有关键作用的290个基因进行检测，最终确立了17个毛细胞白血病特异性的基因表达特征。分析结果显示，非经典核因子κB（NF-κB）通路存在固有激活，同时两种特异性非经典NF-κB抑制剂BIRC2与BIRC3呈现低表达。蛋白质免疫印迹（Western blots）实验证实，在原发性毛细胞白血病样本中，p100的剪切体水平升高，印证了该通路的激活状态。对经典型与变异型毛细胞白血病样本的独立分析显示，二者的mRNA表达谱整体相似，但变异型毛细胞白血病中免疫检查点CD274与PDCD1LG2呈高表达，而FAS呈低表达。本研究结果有助于加深对毛细胞白血病发病机制的理解，同时为该病的治疗策略提供了全新的潜在靶点，并可为毛细胞白血病分子机制的相关研究提供指导。本研究共纳入24例外周血样本：包括13例慢性淋巴细胞白血病（CLL）样本（其中11例经典型毛细胞白血病、2例变异型毛细胞白血病）、8例健康供血者样本，以及3例纯化B淋巴细胞样本。