Single cell RNA sequencing identifies a novel tenogenic heterologous differentiation in endometrial carcinosarcomas

This study presents a single-cell RNA sequencing (scRNAseq) analysis of six carcinosarcomas and two normal endometrial samples, profiling over 96,000 cells. By integrating transcriptomic data with inferred copy number variations (CNVs), immunohistochemistry (IHC), and fluorescence in situ hybridization (FISH), we resolve the complex cellular architecture and differentiation dynamics of these tumors. We identify distinct lineage-specific programs and uncover heterologous differentiation trajectories—including rhabdomyogenic, osteogenic, and a previously undescribed tenogenic lineage defined by SCX, MKX, and TNMD expression. Our results reveal that carcinosarcomas exhibit multilineage plasticity within their mesenchymal component and highlight the power of single-cell analysis to refine tumor classification and uncover hidden developmental programs. Overall design: Six carcinosarcoma samples and two normal endometrial controls were analyzed using scRNAseq. Tumors were dissociated and processed for droplet-based scRNAseq, followed by integration with inferred CNVs, IHC, and FISH validation. The study aimed to characterize epithelial and mesenchymal lineages, identify novel differentiation programs, and explore the genomic architecture underlying carcinosarcoma plasticity.

本研究对6例癌肉瘤（carcinosarcomas）样本与2例正常子宫内膜样本开展单细胞RNA测序（single-cell RNA sequencing, scRNAseq）分析，共覆盖超96000个细胞。本研究将转录组数据与推断的拷贝数变异（copy number variations, CNVs）、免疫组化（immunohistochemistry, IHC）及荧光原位杂交（fluorescence in situ hybridization, FISH）结果整合，解析了这类肿瘤复杂的细胞架构与分化动态。我们鉴定出独特的谱系特异性程序，并揭示了异源分化轨迹——涵盖横纹肌源性、成骨性，以及以SCX、MKX与TNMD表达为特征的此前尚未见报道的腱系谱系。本研究结果显示，癌肉瘤的间叶组分具备多谱系可塑性，同时证实了单细胞分析在优化肿瘤分类、揭示隐藏发育程序上的卓越能力。总体实验设计：本研究采用单细胞RNA测序对6例癌肉瘤样本与2例正常子宫内膜对照样本进行分析。首先对肿瘤组织进行解离，通过液滴法完成单细胞RNA测序，随后将测序数据与推断的拷贝数变异、免疫组化及荧光原位杂交验证结果进行整合。本研究旨在表征上皮与间叶谱系、鉴定新型分化程序，并探究癌肉瘤可塑性背后的基因组架构。