Suzuki et al. employed siRNA to down-regulate the DNMT1 expression in NSCLC cell line NCIH1299, and resulted in >80% reduction of promoter methylation in RASSF1A, CDKN2A (alias P16/INK4a), CDH1 and HPP1 gene. Here, CDKN2A is linked to non-small cell lung carcinoma.