DNA methylation in tumor and matched non-cancerous tissues from non-small cell lung cancer (NSCLC) patients

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We used MethyLight assays to analyze the DNA methylation status of 27 genes in 49 paired cancerous and non-cancerous tissue samples from non-small cell lung cancer (NSCLC) patients who underwent surgical resection. Seven genes (RARB, BVES, CDKN2A, KCNH5, RASSF1, CDH13, and RUNX) were found to be methylated significantly more frequently in tumor tissues than in non-cancerous tissues. Only methylation of CCND2 and APC was frequently detected in non-cancerous tissues, supporting the hypothesis that the methylation of these two genes is a pre-neoplastic change and may be associated with tobacco smoking exposure. Methylation of any one of eight genes (RASSF1, DAPK1, BVES, CDH13, MGMT, KCNH5, RARB, or CDH1) was present in 80% of NSCLC tissues, but only in 14% of non-cancerous tissues. Detection of methylation of these genes in blood might have utility in monitoring for and detecting tumor recurrence in early stage NSCLC patients after complete and presumably curative surgical resection.