单细胞RNA测序（scRNA-seq）和批量RNA测序（bulk RNA-seq）由于其解析细胞异质性的能力，正日益被广泛应用于筛选与癌变相关的基因。本研究旨在通过scRNA-seq与bulk RNA-seq相结合，揭示胃癌（GC）生长和转移的癌干细胞（CSCs）标记基因CXCR4的分子机制。GC相关的scRNA-seq数据从GEO数据库下载，在UMAP聚类分析后，利用K-means算法排除非恶性细胞。批量RNA-seq数据和临床样本信息从UCSC Xena数据库下载。GO和KEGG通路分析验证了基因与通路之间的相关性。利用体外和体内功能实验检测受扰动的CXCR4对恶性表型、肿瘤发生和肝转移的影响。在GC组织样本中鉴定出大量高变异基因。选取前20个主成分，并将细胞分为6种细胞类型。惡性上皮細胞的C4细胞聚类可能为CSCs。将CXCR4单独挑选为CSCs的标记基因。CXCR4表达高的GC患者生存率较差。CXCR4的沉默抑制了CSCs的恶性表型，同时在裸鼠体内抑制了肿瘤发生和肝转移。CSC标记基因CXCR4可能是促进CSCs的恶性表型、肿瘤生长和肝转移的关键基因。© 2023. Nature Publishing Group UK.

Single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (bulk RNA-seq) are increasingly used for screening genes involved in carcinogenesis due to their capacity for dissecting cellular heterogeneity. This study aims to reveal the molecular mechanism of the cancer stem cells (CSCs) marker gene CXCR4 in gastric cancer (GC) growth and metastasis through scRNA-seq combined with bulk RNA-seq. GC-related scRNA-seq data were downloaded from the GEO database, followed by UMAP cluster analysis. Non-malignant cells were excluded by the K-means algorithm. Bulk RNA-seq data and clinical sample information were downloaded from the UCSC Xena database. GO and KEGG pathway analyses validated the correlation between genes and pathways. In vitro and in vivo functional assays were used to examine the effect of perturbed CXCR4 on malignant phenotypes, tumorigenesis, and liver metastasis. A large number of highly variable genes were identified in GC tissue samples. The top 20 principal components were selected, and the cells were clustered into 6 cell types. The C4 cell cluster from malignant epithelial cells might be CSCs. CXCR4 was singled out as a marker gene of CSCs. GC patients with high CXCR4 expression had poor survival. Knockdown of CXCR4 inhibited the malignant phenotypes of CSCs in vitro and curtailed tumorigenesis and liver metastasis in nude mice. CSC marker gene CXCR4 may be a key gene facilitating malignant phenotypes of CSCs, which thus promotes tumor growth and liver metastasis of GC.© 2023. Nature Publishing Group UK.