Moreover, our current study also showed that expression of RBM5 protein in NSCLC tissues was negatively correlated with tobacco smoke, The data that decreased expression of RBM5 protein was more frequent in smokers than in non-smokers suggest tobacco carcinogens may lead to the loss of RBM5 expression in NSCLC, which is in agreement with previous studies that had shown deletions at 3p21.3 were the earliest lesions in lung cancer, and were associated with smoking alone [15]. This evidence concerns the gene RBM5 and lung cancer.