Identification of prognostic biomarkers for gastric cancer by gene expression analysis

4623 Background: Endoscopic biopsy before chemotherapy provides an excellent opportunity for studying biomarkers related to therapy-induced tumor responses or overall survival. This study was designed to identify prognostic biomarkers in patients with unresected gastric cancer. Methods: Samples were taken from histologically proved primary gastric cancers in 40 patients before chemotherapy. Microarray analysis was performed using Affymetrix HG-U133Plus2.0 GeneChips after RNA quality checks of the samples. Correlations between gene expression data and survival time were statistically evaluated with a univariate Cox proportional-hazards model. Identified genes were validated by real time RT-PCR analysis in same 40 test-set samples. Then, PCR-validated genes were evaluated for independent samples (validation set) to predict survival. Results: We obtained 185 candidate genes that were significantly associated with survival (p<0.005) on univariate testing in the 40 test-set sample. Real time RT-PCR analysis id...