Molecular testing in colorectal cancer

Colorectal cancer (CRC) is a complex disease, in which at least three distinct molecular pathways to carcinogenesis and four consensus molecular subtypes have been described. There has, therefore, 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 targeted therapeutics, and testing of microsatellite instability (MSI) status in individual tumors. Molecular biomarkers with predictive or prognostic significance in CRC are increasingly utilized in the clinical management of these patients, with a particular focus on the EGFR signaling pathway and immunotherapies. In addition, high-throughput molecular testing of CRCs in cancer-specific mutation panels by next-generation sequencing have become increasingly utilized as diagnostic assays in the clinical laboratory. 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 new targeted therapeutics for the treatment of CRC.