Characteristics of circadian rhythm-related genes and establishment of a prognostic scoring system (CRscore) for lung adenocarcinoma with experimental verification

Background Non-small-cell lung cancer (NSCLC) is one of the most common malignant tumors worldwide. Lung adenocarcinoma (LUAD), which is the m ain subtype of NSCLC, has a poor prognosis. In recent years, circadian rhythm (CR)-related genes (CRRGs) have demonstrated associations with tumor occurrence and development, but the relationship between CRRGs and LUAD is not clear. Methods Based on data from The Cancer Genome Atlas and Gene Expression Omnibus databases, we explored the biological function and immune cell infiltration of LUAD in different CR clusters and quantified CR genes using principal component analysis. Then, we built a CR scoring system (CRscore) to explore the relationship between CRRGs and LUAD prognosis. Results Patients were divided into three clusters (A, B, and C). Biological characteristics, such as survival, immune cell infiltration, and gene enrichment, were significantly different among the three clusters. We then established the usefulness of the CR score, which could effectively predict the prognosis of LUAD. Specifically, patients with a high CR score had a better prognosis and were more sensitive to chemotherapy than patients with a low CR score. Conclusion CRRGs can be used to assess the prognosis of patients with LUAD. Quantification of CR using the CRscore tool in patients with LUAD could help to guide personalized cancer immunotherapy strategies in the future. Thus, the CRscore may be a powerful prognostic tool for LUAD.