Examination of gene deletion as a mechanism of RBM5 downregulation in tobacco smoke-associated lung cancer

Abstract

RBM5 is a tumour suppressor gene with substantially decreased expression in most lung cancers, especially in smokers, that may result from gene deletion. The objective of this study was to determine if significantly decreased levels of RBM5 expression in the lung cancers of smokers was related to RBM5 deletion. Using DNA from patient lung tissue, RBM5 gene copy number was quantified by quantitative polymerase chain reaction. Although deletions were detected in the lung specimens, RBM5 gene copy number was not significantly decreased in lung tumours. RBM5 deletions were detected in the non-tumour DNA of smokers, but not in the never-smokers, indicating that RBM5 gene deletion might be related to smoking. In conclusion, it appeared as though RBM5 was downregulated by more than one mechanism, which included gene deletion. Further analyses must be carried out to examine other mechanisms by which RBM5 is downregulated.