混合表型急性白血病（MPAL）是一种罕见的白血病亚组，其特征是母细胞具有髓系和淋巴系谱系特征，诊断和治疗非常困难。更好地表征 MPAL 对于了解亚型异质性及其与急性髓系白血病 (AML) 和急性淋巴细胞白血病 (ALL) 的比较至关重要。因此，我们对儿科 MPAL 骨髓 (BM) 样本进行了单细胞 RNA 测序 (scRNAseq)，以绘制 MPAL 原始细胞和微环境景观的颗粒图。我们分析了来自 9 个儿科 MPAL BM 样本的 40,000 多个细胞，以生成单细胞B/骨髓 (B/My) 和 T/骨髓 (T/My) MPAL 的细胞转录组景观。使用无监督的单细胞方法对细胞进行聚类，并对恶性母细胞和免疫簇进行注释。通过比较 MPAL 与正常 BM、AML 和 ALL 的转录组图谱，进行差异表达分析，以鉴定 B/My 和 T/My MPAL 母细胞特异性特征。进行基因集富集分析 (GSEA)，并比较 MPAL 亚型中显着富集的途径。B/My 和 T/My MPAL 母细胞显示出不同的母细胞特征。转录组分析显示，B/My MPAL 谱与 B-ALL 和 AML 样本重叠。同样，T/My MPAL 与 T-ALL 和 AML 样本有重叠。与 AML、ALL 和健康 BM 相比，两种 MPAL 亚型的母细胞中过度表达的基因包括 MAP2K2 和 CD81。亚型特异性基因包括 B/My 的 HBEGF 和 T/My 的 PTEN。这些标记集根据表达谱分离大量 RNA-seq AML、ALL 和 MPAL 样本。将 T/My MPAL 与 ETP、近 ETP 和非 ETP T-ALL 进行比较的分析表明，T/My MPAL 与 ETP-ALL 病例有更大的重叠。成人和儿童样本之间 MPAL 亚型的比较显示了相应亚型的类似转录组景观。基于对诱导化疗的反应，在 MPAL 样本中观察到转录组差异，包括复发样本中 IL-16 通路的选择性上调。我们首次描述了儿科 MPAL 的单细胞转录组景观，并证明 B/My和 T/My MPAL 具有彼此不同的 scRNAseq 配置文件、AML 和 ALL。根据对治疗的反应，转录组图谱存在差异，但需要更大规模的研究来验证这些发现。© 2023。BioMed Central Ltd.，Springer Nature 旗下公司。

Mixed phenotype acute leukemia (MPAL), a rare subgroup of leukemia characterized by blast cells with myeloid and lymphoid lineage features, is difficult to diagnose and treat. A better characterization of MPAL is essential to understand the subtype heterogeneity and how it compares with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Therefore, we performed single-cell RNA sequencing (scRNAseq) on pediatric MPAL bone marrow (BM) samples to develop a granular map of the MPAL blasts and microenvironment landscape.We analyzed over 40,000 cells from nine pediatric MPAL BM samples to generate a single-cell transcriptomic landscape of B/myeloid (B/My) and T/myeloid (T/My) MPAL. Cells were clustered using unsupervised single-cell methods, and malignant blast and immune clusters were annotated. Differential expression analysis was performed to identify B/My and T/My MPAL blast-specific signatures by comparing transcriptome profiles of MPAL with normal BM, AML, and ALL. Gene set enrichment analysis (GSEA) was performed, and significantly enriched pathways were compared in MPAL subtypes.B/My and T/My MPAL blasts displayed distinct blast signatures. Transcriptomic analysis revealed that B/My MPAL profile overlaps with B-ALL and AML samples. Similarly, T/My MPAL exhibited overlap with T-ALL and AML samples. Genes overexpressed in both MPAL subtypes' blast cells compared to AML, ALL, and healthy BM included MAP2K2 and CD81. Subtype-specific genes included HBEGF for B/My and PTEN for T/My. These marker sets segregated bulk RNA-seq AML, ALL, and MPAL samples based on expression profiles. Analysis comparing T/My MPAL to ETP, near-ETP, and non-ETP T-ALL, showed that T/My MPAL had greater overlap with ETP-ALL cases. Comparisons among MPAL subtypes between adult and pediatric samples showed analogous transcriptomic landscapes of corresponding subtypes. Transcriptomic differences were observed in the MPAL samples based on response to induction chemotherapy, including selective upregulation of the IL-16 pathway in relapsed samples.We have for the first time described the single-cell transcriptomic landscape of pediatric MPAL and demonstrated that B/My and T/My MPAL have distinct scRNAseq profiles from each other, AML, and ALL. Differences in transcriptomic profiles were seen based on response to therapy, but larger studies will be needed to validate these findings.© 2023. BioMed Central Ltd., part of Springer Nature.