Transcriptome profile of human colorectal adenomas.

Background: Colorectal cancers are believed to arise predominantly from adenomas. Although these precancerous lesions have been subjected to extensive clinical, pathological, and molecular analyses, little is currently known about the global gene expression changes accompanying their formation. Results: To characterize the molecular processes underlying the transformation of normal colonic epithelium, we compared the transcriptomes of 32 prospectively collected adenomas with those of normal mucosa from the same individuals. Important differences emerged not only between the expression profiles of normal and adenomatous tissues, but also between those of small and large adenomas. A key feature of the transformation process was the remodeling of the Wnt pathway reflected in patent over- and underexpression of 78 known components of this signaling cascade. Conclusions: Our transcriptomic profiles of normal colonic mucosa and colorectal adenomas shed new light on the early stages of colorectal tumorigenesis. Keywords: tissue comparison Pedunculated, sporadic colorectal polyps and corresponding normal mucosa were obtained during colonoscopies. The tissues were collected prospectively with informed patient consent and the approval of the local Human Research Ethics Committee.