Abstract 4089: Identification of a DNA methylation marker to detect the presence of lymph node metastases of gastric cancers

Accurate detection of the presence of lymph node metastases of gastric cancers (GCs) is clinically important. However, current methods to detect it are unsatisfactory. As a marker, DNA methylation is advantageous because it is biologically and chemically stable and the DNA methylation profile is not disturbed by a small population of cells. Therefore, we focused on aberrant DNA methylation in GCs as a possible marker to detect the presence of lymph node metastases. We first performed genome-wide methylation analyses by Illumina Infinium HumanMethylation450 BeadChip array using three metastatic lymph nodes (MLNs) and three primary GCs without MLNs, and isolated 31 differentially methylated CpG sites. Then, using primary GCs with and without MLNs (screening set; 28 GCs with MLNs and 10 GCs without MLNs), their methylation levels were analyzed by quantitative PCR-based methods. Among the 31 regions, 10 regions showed higher methylation levels in GCs with MLNs than in GCs without MLNs (P < 0.05). In further analysis of the 10 regions using another sample set (validation set; 129 GCs with MLNs and 20 GCs without MLNs), hypermethylation of a region (cg06436185) in GCs with MLNs was validated, and the presence of lymph node metastases was detected with sensitivity of 43% and specificity of 85%. These results indicated that the methylation status of the cg06436185 region is a good marker to detect the presence of lymph node metastases of GCs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4089. doi:1538-7445.AM2012-4089