Tumor immune microenvironment and response of immunotherapy in patients with colorectal cancer

<b>Aim:</b> Biomarkers, such as PD-L1, have enabled significant progress in predicting the efficacy of immunosuppressants. However, they may not accurately predict the benefit degree from immunotherapy. Therefore, we associated PD-L1 with tumor-infiltrating lymphocytes for accurate guidance in immunotherapy. <b>Methods:</b> The expressions of diverse proteins in 68 patients with positive PD-L1 expression were detected. The response to immunotherapy and its clinical results were observed and analyzed. <b>Results:</b> The overall response rate of immunotherapy differed significantly among groups (75%; 57.58%; 10%; and 0), as did the 3-year overall survival rates (72.73%, 54.84%, 11.11%, and 0). <b>Conclusion:</b> We identified four immune subtypes of colorectal cancer with different tumor-infiltrating lymphocytes (TILs), and constructed a highly operable method for immunotyping to predict the immunotherapy efficacy. We identified four immune subtypes of colorectal cancer with different TILs, their distribution, and different immune responses and constructed a highly operable and simple method for immunotyping. Classification of immune microenvironment in colorectal cancer – four immune subtypes of colorectal cancer with different TILs and different immune responses were determined. Immune typing method – a highly operable and simple method for immunotyping was constructed. The necessity of tumor immunophenotyping – the tumor immune microenvironment is heterogeneous and patients with different immune microenvironments responded differently to PD-1 and PD-L1 inhibitors. Differences in therapeutic efficacy among different immune subtypes – the HIRG had a very good curative effect, the LIRG had a good curative effect and the IDG and IRG had poor or even ineffective curative effects. The significance of immune classification – TILs can be used as new biomarkers to predict the efficacy of immunotherapy, which is important for guiding individualized immunotherapy.