Expression and potential mechanism of metabolism-related genes and CRLS1 in non-small cell lung cancer.

Cardiolipin (CL) is a phospholipid localized in the mitochondria, which is essential for mitochondrial structure and function. Human cardiolipin synthase 1 (CRLS1) is important in regulating phosphatidylglycerol (PG) remodeling and CL biosynthesis. However, the expression and distinct prognostic value of CRLS1 in neoplasms, including non-small cell lung cancer (NSCLC), is not well established. In the present study, the mRNA expression of CRLS1 was investigated using Oncomine analysis and the prognostic value was assessed using the Kaplan-Meier plotter database for patients with NSCLC. The results of the analyses indicated that the expression of CRLS1 in lung cancer was lower, compared with that in normal lung tissues. Notably, a high expression of CRLS1 was found to be associated with improved overall survival (OS) in all patients with NSCLC and lung adenocarcinoma (Ade). However, this was not observed in patients with squamous cell carcinoma (SCC). The results also demonstrated an association between the mRNA expression of CRLS1 and the clinicopathological parameters of patients with NSCLC, including sex, smoking status, tumor grade, clinical stage, lymph node status and chemotherapy. These results indicated that CRLS1 was associated with improved prognosis in patients with NSCLC, particularly at an early stage (T1N1M0). In addition, it was revealed that CRLS1 was co-expressed with well-known genes associated with metabolism using Gene Ontology term enrichment analysis. Kyoto Encyclopedia of Genes and Genomes pathway analysis also showed that tumor-related metabolism and the mitogen-activated protein kinase (MAPK) signaling pathways were enriched with CRLS1-co-expression genes. The results of the present study suggested that CRLS1 may be a novel tumor suppressor involved in regulating lipid and seleno-amino acid metabolism in the tumor microenvironment, and suppressing the MAPK signaling pathway during tumorigenesis and development. Comprehensive evaluation of the expression, prognosis and potential mechanism of CRLS1 is likely to promote an improved understanding of the complexity of the molecular biology of NSCLC.