KRAS and non-small cell lung carcinoma: Here, we showed that demethylation drug treatment causes restoration of miR-199b expression in K-Ras mutant NSCLC cells, and mutant K-Ras-dependent inhibition of miR-199b expression was abolished by demethylation drug treatment in NSCLC cells, suggesting that decreased expression of miR-199b in K-Ras mutant NSCLC cells was associated with the methylation status of the miR-199b promoter.