OSM and adenoma: To confirm the gene expression data obtained from microarray analysis, eight genes were selected for validation by RT-qPCR (SIM2, ESM1, SFRP4, IL8, IL6, OSM, ETV4 and RETNLB) on 25 adenomas and 16 adenocarcinomas (the initial 10 adenoma/adenocarcinoma paired samples and additional 15 adenomas and 6 adenocarcinoma samples).