A systematic approach to the metastatically relevant microRNA landscape

Identification of differentially expressed microRNAs in Colorectal Cancer Distant metastasis is the major determinant of patient outcome in colorectal cancer and microRNAs have emerged as an increasingly important class of molecules which can regulate several steps of the metastatic cascade. By systematically analysing the miR expression profiles of resected metastasis-, corresponding primary tumor- and normal tissues of colorectal cancer patients, we were able to delineate a miR-signature indicative of the metastatically critical microRNA landscape. 9 colorectal cancer patients were profiled comprising 5 patients with tissues from the primary tumor, normal mucosa, secondary metastasis and the background tissue in which the metastasis ocurred. In the remaining 4 patients, one of these four tissue entitities is missing. One patient had two synchronous primary tumors, one in the colon and the other in the rectum.