Gene expression analysis of 3 node positive vs 3 node negative intestinal type gastric cancers by gene array technology.

Gastric cancer is one of the most common causes of cancer-related deaths worldwide. The lymph node status represents the strongest prognostic factor. Due to its extremely poor prognosis, the identification of novel therapeutic targets is urgently needed. Therefore, we aimed to assess differentially expressed genes in nodal negative versus nodal positive intestinal type gastric carcinoma by GeneChip array technique. The transcriptional profile of 6 gastric cancers with and without lymphatic dissemination was analyzed. A total of 115 transcripts were found to be up- and 219 to be down-regulated in node positive compared with node negative gastric cancers. Next we searched for differentially expressed GPCRs. We identified 52 GPCRs and GPCR-related genes, which were up- or down-regulated with a fold change factor greater 1.5. Tissue samples of gastric cancer were obtained surgically at the Charité University Hospital Berlin. Tumours were classified by histology according to the WHO and Laurén classification. Fresh frozen tissue of 6 intestinal type gastric carcinoma cases was used for Affymetrix GeneChip analysis (nodal negative: 3 patients; nodal positive: 3 patients; female-male-ratio: 1:2). Total RNA was isolated from each sample. Subsequently to gene array analysis the transcription of candidate genes was validated by real-time RT-PCR on an independent series of 37 gastric cancers.