Mutational and Expressional Analysis of ATG5 Gene in Non-Small Cell Lung Cancers

ABSTRACT

PURPOSE: Several lines of evidence have indicated that perturbations of autophagy are involved in the development of many human diseases, including cancer. The autophagy-related genes (ATG) encode proteins that play important roles in autophagic processes. The aim of this study was to see whether alterations of the ATG5 protein expression and somatic mutations of the ATG5 gene are present in human non-small cell lung cancers (NSCLCs). MATERIALS AND METHODS: We analyzed the ATG5 somatic mutations in 45 NSCLCs by performing single-strand conformation polymorphism (SSCP). We examined the ATG5 protein expression in 45 NSCLCs by performing immunohistochemistry. RESULTS: The SSCP analysis revealed no evidence of somatic mutation in the DNA sequences encoding the ATG5 gene in the 45 NSCLCs. On the immunohistochemistry, ATG5 protein was expressed in the normal bronchial epithelial cells, while it was lost in 9 (20%) of the NSCLCs. CONCLUSION: Our data indicates that ATG5 is altered in NSCLC at the expressional level, but not at the mutational level. The data also suggests that the loss of expression of ATG5 might play a role in the pathogenesis of NSCLC by altering autophagic and apoptotic cell death.