Identification and validation of a prognostic signature based on six immune-related genes for colorectal cancer

Abstract

Abstract Background Colorectal cancer (CRC) is a prevalent malignancy with high death and morbidity rates. Even though the significant efficacy of immunotherapy is well-established, it is only beneficial for a limited number of individuals with CRC. Methods Differentially expressed immune-related genes (DE-IRGs) were retrieved from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Immport databases. The prognostic signature comprising DE-IRGs was developed by means of Univariate, Lasso, and Multivariate Cox-regression analyses. Following this, a nomogram integrating the independent prognostic factors was also developed. CIBERSORT was applied to ascertain the immune cell infiltration (ICI). Furthermore, wound healing, colony formation, migration, and invasion assays were executed to study the involvement of ACTG1 in CRC. Results A signature including six DE-IRGs was developed. It could estimate the rate of overall survival (OS) accurately for the TCGA and GSE38832 cohorts. The risk score (RS) of the signature was an independent factor for OS. Moreover, a nomogram encompassing age, RS, and pathological T could accurately predict the long-term OS probability of individuals with CRC. The high-risk group had an elevated proportion of ICI relative to the low-risk group, including native B cells. Additionally, ACTG1 expression was upregulated, which supported the proliferation, migration, and invasion abilities of CRC cells. Conclusions An immune-related prognostic signature was developed for predicting OS and to ascertain the immune status in individuals with CRC. It could provide new insights into accurate immunotherapy for individuals with CRC. Moreover, ACTG1 can possibly serve as a new immune biomarker.