DNA Methylation in Lung Cancer

Abstract

To the Editor: Brock et al. (March 13 issue)1 report that gene methylation, especially methylation of the p16 and CDH13 genes, was associated with early recurrence of stage I non–small-cell lung cancer (NSCLC). We previously evaluated the relationship between methylation of five genes and prognosis in 351 Japanese patients who underwent resection for NSCLC and found that only p16 methylation was significantly related to a poor prognosis.2 We analyzed our results again and found that methylation of both p16 and CDH13 was also associated with a poor prognosis in 199 patients with lung adenocarcinomas, even when these tumors were limited to stage I disease. We also reported that methylation of p16 and CDH13 was significantly less frequent in epidermal growth factor receptor (EGFR)-mutant tumors than in EGFR wildtype tumors, suggesting less involvement of methylation of these genes in EGFR-related tumorigenesis.3 Our findings provide support for those of Brock et al. with regard to the prognostic significance of gene methylation in NSCLC.