Genome-wide gene expression differences between Crohn’s and ulcerative colitis from endoscopic pinch biopsies:

To identify pathogenic processes underlying these disease subtypes, using single endoscopic pinch biopsies, we elucidated gene expression patterns of active and inactive areas of UC and CD, and compared these to infectious colitis and healthy controls. An unsupervised classification of a total of 36 samples yielded promising separation between IBD affected, unaffected, non-IBD colitis and normal controls, suggesting distinctive gene expression patterns for each sample type. The Significance Analysis of Microarays (SAM) software to select biologically significant changes in gene expression between groups. The criteria selected for SAM analysis are, a median false discovery rate (FDR) ≤ 0.00001%, fold change >2, and a Log2 mean expression index > 6.64.