Microarray gene-expression data to validate a 17-gene biomarker obtained from excessive meta-analysis to test its PDAC specificity in the presence of pancreatitis tissues.

Clinical signs and radiographic findings of PDAC and pancreatitis are often indistinguishable, highlighting the need of a PDAC biomarker to be insensitive to pancreatitis. Therefore we validated a biomarker signature of 17-genes in this gene expression data containing PDAC, non-tumor pancreatic and pancreatitis of fresh-frozen and formalin-fixed paraffin-embedded tissues. Total RNA was obtained from 3 FF and 1 FFPE non-tumor pancreatic, 3 FF and 3 FFPE PDAC, 4 FFPE non-tumor pancreatic, and 10 FFPE pancreatitis tissues. Data was quantile normalized and manufactor IDs were matched to unique Entrez IDs using the probe with the largest interquartile range. Subsequently, classification performance of the biomarker genes were tested by distinguishing between PDAC and non-tumor (adjacent pancreas and pancreatitis) tissues.