Molecular Testing in Colorectal Cancer

Colorectal cancer (CRC) is a complex disease, in which at least three distinct molecular pathways to carcinogenesis have been described. There has been an increasing role for molecular testing in the diagnosis and clinical management of CRC and a rapid expansion in the molecular technologies available for use in the clinical laboratory. Current clinical recommendations for molecular testing in CRCs are aimed at identification of hereditary colon cancer syndromes, predicting response to antiepidermal growth factor receptor (EGFR) monoclonal antibody therapies, and testing of microsatellite instability status in individual cancers. Molecular biomarkers with predictive or prognostic significance in CRC are increasingly utilized in clinical management, with a particular focus on the EGFR signaling pathway. In addition, high-throughput molecular testing of CRCs in cancer-specific mutation panels by multiplexed assays and new sequencing technologies have been developed and are quickly becoming validated diagnostic assays for use in the clinical laboratory. Therefore, the standard-of-care recommendations for molecular testing of CRCs will likely continue to evolve as we advance in our understanding of the molecular mechanisms of disease and rapidly develop targeted therapeutics for the treatment of CRC.