Background/Aim: The development of colon cancer is influenced by the tumour immune microenvironment, in which specific immune cell subsets may be useful predictors for patient's clinical outcome and devising treatment strategies. Materials and Methods: The distribution of tumour-infiltrating immune cell subpopulations of three cohorts of The Cancer Genome Atlas (n=225), GSE39582 (n=493), and GSE17536 (n=137) datasets were analysed on the basis of single cell RNA sequencing data via the Cibersortx software. A prognostic model was constructed via a penalised Cox regression model with least absolute shrinkage and selection operator (LASSO) penalty according to the one standard error rule. Results: Conventional type 2 dendritic cells were correlated with a good prognosis, whereas NLRP3-expressing macrophages, C1QCexpressing tumour-associated macrophages, and GALTBexpressing B cells were correlated with a poor prognosis. We constructed a prognostic model based on prognosis related cell subsets including nine specific immune cell subsets. By using the LASSO method, we found that the model had a superior prediction ability in all three cohorts of patients.
Conclusion: Multiple immune cell subpopulations in the tumour microenvironment are associated with the prognosis of colon cancer. The established prognostic model has important clinical value in predicting the clinical outcome of patients with colon cancer and in treatment decision.Colon cancer is one of the most common aggressive tumours worldwide (1). Current treatment methods, including surgery, chemotherapy, radiotherapy, or their combination have significantly improved patient survival rate (2). In addition, the application of biomarkers enables effective screening and helps identify patients with a high risk of relapse and resistance to therapy, which in turn makes individualised treatment plans and follow-up strategies possible. In particular, treatment modalities involving immune checkpoint inhibitors have improved the survival of patients with malignant tumours (3). However, in patients with colon cancer, the therapeutic efficacy of immune checkpoint inhibitors is poor, except for those with deficient mismatch repair (dMMR) associated with a high degree of microsatellite instability (4).The immune tumour microenvironment (TME) is now considered as a potential target for immunotherapy (5). The TME includes tumour cells, stromal cells such as fibroblasts, endothelial cells, and immune cells, and non-cellular components of extracellular matrix such as collagen, fibronectin, hyaluronan, and laminin. The interaction of tumours with cellular and noncellular components of the TME results in the generation of a complex network that can be used by tumour cells to ensure favourable conditions for their proliferation, dissemination, and resistance to therapy (6). In colon cancer, CD8-positive T cells, tertiary lymphoid structures, regulatory T cells, and macrophages have shown strong correlation with prognosis (7). Recently, Zhang et al. (8) performed systematic evaluat...