Single Cell RNA Sequencing in Colorectal Cancer Immunology: Recent Updates, Application, and Emerging Challenges

Colorectal cancer poses a major global health issue, profoundly affecting both mortality and morbidity rates across the world. A key obstacle in understanding the pathogenesis of colorectal cancer lies in its high inter-patient and spatial heterogeneity, making standard treatments ineffective. Commonly, the study on colorectal cancer relies on bulk RNA sequencing, offering an average gene expression profile for a heterogenous cell population. However, this approach obscures the heterogeneous characteristics of the cancer cells and hinders a comprehensive understanding of the complex interplay among different cell populations. Recently, the advent of single-cell RNA sequencing has been revolutionary, enabling researchers to analyze individual immune cells and overcome the limitations of bulk RNA sequencing. Through single-cell RNA sequencing, researchers have gained insights into the dynamic nature of the immune response to cancer and potential targets for immunotherapy. In this review, we discuss the technical aspects of single-cell RNA sequencing, the application of single-cell RNA sequencing in cancer immunology, and the potential of single-cell RNA in clinical settings. We believe that harnessing singlecell RNA sequencing in cancer research holds immense potential to drive the development of personalized immunotherapies, aiming to improve patient outcomes in colorectal cancer.