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Pathology Research International
Volume 2012 (2012), Article ID 597497, 14 pages
Review Article

Molecular Events in Primary and Metastatic Colorectal Carcinoma: A Review

1Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 0W8
2Royal University Hospital, Room 2868 G-Wing, 103 Hospital Drive, Saskatoon, SK, Canada S7N 0W8
3Department of Surgery, University of Saskatchewan, Saskatoon, SK, Canada S7N 0W8

Received 25 December 2011; Accepted 23 February 2012

Academic Editor: Marco Volante

Copyright © 2012 Rani Kanthan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Colorectal cancer (CRC) is a heterogeneous disease, developing through a multipathway sequence of events guided by clonal selections. Pathways included in the development of CRC may be broadly categorized into (a) genomic instability, including chromosomal instability (CIN), microsatellite instability (MSI), and CpG island methylator phenotype (CIMP), (b) genomic mutations including suppression of tumour suppressor genes and activation of tumour oncogenes, (c) microRNA, and (d) epigenetic changes. As cancer becomes more advanced, invasion and metastases are facilitated through the epithelial-mesenchymal transition (EMT), with additional genetic alterations. Despite ongoing identification of genetic and epigenetic markers and the understanding of alternative pathways involved in the development and progression of this disease, CRC remains the second highest cause of malignancy-related mortality in Canada. The molecular events that underlie the tumorigenesis of primary and metastatic colorectal carcinoma are detailed in this manuscript.