mRNA expression data from human adenocarcinomas of the stomach

Gastric cancer can be divided in two major histological subtypes: diffuse and intestinal-type adenocarcinomas. Since both types diverge in many clinical and molecular characteristics, is widely accepted that both represent distinct disease entities that may benefit from different therapeutic approaches. The diffuse type is explicitly more invasive and affected patients possess extremely poor prognosis. Gene expression profiling studies identified numerous genes with differences in mRNA expression between the two types. However, little overlap of published gene lists exists forcing the need for further and more comprehensive analyses. We used microarray-based whole-transcriptome expression profiling to characterize the gene expression profile of both histologiocal types and to identify differentially expressed genes. Tumor tissue samples were controlled for tumor contents higher than 75% and pathologically evaluated by two independent blinded pathologist. Total RNA was extracted and controlled for high quality (Agilent Bioanalyzer RIN above 7). Messenger RNA population was labelled and hybrizied on Affymetrix microarrays. The obtained gene expression data was bioinformatically and statistically analyzed with the goal to identify differentially expressed genes.