美国斯隆·凯特琳纪念癌症中心Ross L. Levine小组近日取得一项新成果。经过不懈努力，他们利用单细胞突变分析了骨髓恶性肿瘤克隆的进化。相关论文于2020年10月28日在线发表于《自然》杂志。

为了揭示骨髓恶性肿瘤的克隆结构，探究人员对来自123位患者的146个样本进行了单细胞突变分析。

研究发现急性骨髓性白血病（AML）是由少数克隆控制，这些克隆经常在表观遗传调控因子中同时发生突变。相反，信号基因的突变通常频繁发生在不同的亚克隆中，这与克隆多样性的增加是一致的。研究人员描绘了每个样本的克隆轨迹，并发现了协同促进克隆扩增的突变组合。最后，研究人员将蛋白质表达与突变分析相结合揭示了体细胞基因型和具有免疫表型的克隆结构。该发现为了解髓样转化的发病机理以及克隆复杂性如何随疾病的进展而发展提供了基础。

据悉，包括AML在内的骨髓恶性肿瘤是由造血干细胞和获得体细胞突变的祖细胞扩增造成的。大量分子生物学分析表明突变是逐步获得的：具有高等位基因频率的突变出现在白细胞生成早期，而具有低等位基因频率的突变则被认为是随后出现的。尽管批量测序可以提供有关白血病生物学和预后的信息，但是它无法区分同一克隆中发生了哪些突变也无法准确测量克隆的复杂性或确定突变的顺序。

附：英文原文

Title: Single-cell mutation analysis of clonal evolution in myeloid malignancies

Author: Linde A. Miles, Robert L. Bowman, Tiffany R. Merlinsky, Isabelle S. Csete, Aik T. Ooi, Robert Durruthy-Durruthy, Michael Bowman, Christopher Famulare, Minal A. Patel, Pedro Mendez, Chrysanthi Ainali, Benjamin Demaree, Cyrille L. Delley, Adam R. Abate, Manimozhi Manivannan, Sombeet Sahu, Aaron D. Goldberg, Kelly L. Bolton, Ahmet Zehir, Raajit Rampal, Martin P. Carroll, Sara E. Meyer, Aaron D. Viny, Ross L. Levine

Issue&Volume: 2020-10-28

Abstract: Myeloid malignancies, including acute myeloid leukaemia (AML), arise from the expansion of haematopoietic stem and progenitor cells that acquire somatic mutations. Bulk molecular profiling has suggested that mutations are acquired in a stepwise fashion: mutant genes with high variant allele frequencies appear early in leukaemogenesis, and mutations with lower variant allele frequencies are thought to be acquired later1–3. Although bulk sequencing can provide information about leukaemia biology and prognosis, it cannot distinguish which mutations occur in the same clone(s), accurately measure clonal complexity, or definitively elucidate the order of mutations. To delineate the clonal framework of myeloid malignancies, we performed single-cell mutational profiling on 146 samples from 123 patients. Here we show that AML is dominated by a small number of clones, which frequently harbour co-occurring mutations in epigenetic regulators. Conversely, mutations in signalling genes often occur more than once in distinct subclones, consistent with increasing clonal diversity. We mapped clonal trajectories for each sample and uncovered combinations of mutations that synergized to promote clonal expansion and dominance. Finally, we combined protein expression with mutational analysis to map somatic genotype and clonal architecture with immunophenotype. Our findings provide insights into the pathogenesis of myeloid transformation and how clonal complexity evolves with disease progression. 

DOI: 10.1038/s41586-020-2864-x

Source: https://www.nature.com/articles/s41586-020-2864-x