Immune-related gene signature in predicting prognosis of early-stage colorectal cancer patients

Aim Immune-related genes are associated with the prognosis of colorectal cancer (CRC) patients. The aim of this study was to evaluate the impact of an immune-related gene signature (IRGS) in predicting the prognosis of early-stage CRC patients. Methods In total, 309 CRC patients were selected for the identification of prognostic IRGS using the CIT/GSE39582 microarray dataset. Five independent datasets including 1587 CRC patients were divided into a training cohort (n = 566) and two validation cohorts (n = 624 in validation-1 and n = 397 in meta-validation). Prognostic analyses were performed to test the predictive value of IRGS. Results A prognostic IRGS that included 23 immune-related genes was constructed and significantly stratified patients into immune low-vs. high-risk groups in terms of disease-free survival using patients with early-stage disease (I or II) in the training cohort. Similarly, a higher IRGS was correlated with significantly worse prognosis of early-stage patients in validation-1 and meta-validation cohorts. Compared with Oncotype DX colon, we found that IRGS exhibited an improved survival correlation in the training cohort. After integration with clinical characteristics, IRGS remained as an independent prognostic factor in multivariate analysis. Furthermore, IRGS-stratified immune low-risk group patients gained less benefit from adjuvant chemotherapy in the validation-1 cohort. Several biological processes, including inflammatory response, were enriched among genes in identified the immune high-risk group. Consistent with this finding, the IRGS-identified immune high-risk group exhibited significantly increased immune and stromal cell infiltration. Conclusion The proposed prognostic IRGS is a promising system for estimating DFS of colorectal cancer patients, especially those with early-stage disease.