Identification of crucial ubiquitin-associated genes for predicting the effects of immunotherapy and therapeutic agents in colorectal cancer.

• The ubiquitin–proteasome system is significantly disturbed in patients with CRC. • The ubiquitin prognostic risk model can predict the survival rate of CRC patients. • Ubiquitin-associated prognostic genes can forecast the efficacy of immunotherapy. • Sorafenib and regorafenib can treat high ubiquitin-related risk CRC patients. A growing body of research indicates that colorectal cancer (CRC) is significantly influenced by the ubiquitin–proteasome system. Nevertheless, reliable immune landscapes and ubiquitin-associated prognostic markers are still scarce. We systematically analyzed the RNA-seq data of 2,830 ubiquitin-related genes from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). A CRC prognostic risk model was developed based on ubiquitin-associated gene signatures. In-depth multi-dimensional analyses were performed on ubiquitin-related subgroups with high and low risk. Drug response sensitivity for high-risk CRC patients was also predicted. A total of 131 ubiquitin-related differentially expressed genes were retrieved, of which 9 prognostic genes for CRC were ultimately identified and further validated by our clinical CRC tumor and adjacent normal samples. The expression pattern of these 9 ubiquitin-associated genes was found to be strongly related to overall survival, immune cell fractions, and immune-related genes of CRC patients. CRC patients stratified by the ubiquitin prognostic model exhibited distinct clinicopathological characteristics and immune landscapes. A comprehensive framework for personalized medicine prediction identified regorafenib and sorafenib as the most promising therapeutic agents for high ubiquitin-related risk CRC patients, which was confirmed in cell viability assays. Ubiquitin characteristics can reflect CRC prognosis and help develop innovative biomarkers for precision treatment. [ABSTRACT FROM AUTHOR]