Advanced insights on tumor-associated macrophages revealed by single-cell RNA sequencing: The intratumor heterogeneity, functional phenotypes, and cellular interactions

• Published in: Cancer letters 2024-03, Vol.584, p.216610-216610, Article 216610
• Main Authors: Yang, Sen, Wang, Mengyi, Hua, Yuze, Li, Jiayi, Zheng, Huaijin, Cui, Ming, Huang, Nan, Liu, Qiaofei, Liao, Quan
• Format: Article
• Language: English
• Subjects: Intratumor heterogeneity; Single-cell RNA sequencing (scRNA-seq); Tumor microenvironment; Tumor-associated macrophages (TAMs)
• ISSN: 0304-3835; 1872-7980
• DOI: 10.1016/j.canlet.2024.216610

Single-cell RNA sequencing (scRNA-seq) is an emerging technology used for cellular transcriptome analysis. The application of scRNA-seq has led to profoundly advanced oncology research, continuously optimizing novel therapeutic strategies. Intratumor heterogeneity extensively consists of all tumor components, contributing to different tumor behaviors and treatment responses. Tumor-associated macrophages (TAMs), the core immune cells linking innate and adaptive immunity, play significant roles in tumor progression and resistance to therapies. Moreover, dynamic changes occur in TAM phenotypes and functions subject to the regulation of the tumor microenvironment. The heterogeneity of TAMs corresponding to the state of the tumor microenvironment has been comprehensively recognized using scRNA-seq. Herein, we reviewed recent research and summarized variations in TAM phenotypes and functions from a developmental perspective to better understand the significance of TAMs in the tumor microenvironment. •The advance of scRNA-seq has revealed the landscape and heterogeneity of tumor microenvironment.•TAMs functioning as main immune cells in tumor microenvironment presents significant spatial and temporal heterogeneity by scRNA-seq.•TAMs have varying phenotypes and functions according to their distribution in tumor stroma.•TAMs fluctuate with tumor progression, thus exhibiting dynamic changes.•ScRNA-seq further describes the developmental TAMs from their origin, polarization, and reprogramming.•Novel phenotypes have been revealed by scRNA-seq, which provides substantial therapeutic targets.