The high heterogeneity of tumor cells and the surrounding immune microenvironment affects the response to treatment in colorectal cancer (CRC) patients. Therefore, there is a need to identify new immune biomarkers to predict the treatment efficacy of CRC. This study aimed to explore the predictive value of tumor-infiltrating lymphocytes (TIL) for survival in CRC patients. Flow cytometry and gated analysis were performed to measure the TILs in tissue samples obtained from 536 CRC patients. The COX regression analysis showed that the CD8 + CD279+ cells had the highest impact of all evaluated TILs on postoperative disease-free survival (DFS) (P < 0.05). The optimal CD8 + CD279+ cutoff point for the prediction of survival was 12.2%. The Kaplan-Meier analysis showed significantly higher DFS in the high CD8 + CD279+ group compared with the low CD8 + CD279+ group (P < 0.05). CD8 + CD279+ cells were associated with DFS in CRC patients with the KARS mutation, MSI/MMR, perineural invasion, and those treated with neoadjuvant chemotherapy and other chemotherapeutic treatments (P < 0.05). After the multivariate adjustment, the expression of CD8 + CD279+ remained an independent risk factor for DFS. Overall, the CD8 + CD279+ cells were identified as an independent prognostic factor in CRC patients and could be used as a potential marker for postoperative DFS.
Keywords: Colorectal cancer; Disease-free survival; Flow cytometry; Tumor-infiltrating lymphocytes.
Copyright © 2022. Published by Elsevier B.V.