Molecular Biomarkers in Colorectal Cancer in the Era of Precision Medicine: A Review

Colorectal cancer (CRC) is a primary cause of death among cancer patients. This heterogeneous disease is characterized by alterations in many molecular pathways during its development. Mutations in RAS, combined with the mismatch repair gene defect are currently widely studied in clinics. Such biomarkers provide information for patient risk classification and for the selecting of the appropriate therapy alternatives. Nevertheless, likely, and robust prognostic markers that can identify “high-risk” CRC patients, who can benefit from adjuvant chemotherapy, in early stages, are currently absent. To solve this gap, genomic information has lately gained interest as a potential technique for estimating the likelihood of recurrence. However, due to several limitations of gene-based signatures, these have not yet been realistically used. In this review, we summarise the multiple molecular markers in clinical use for CRC, highlight potential indicators that might become indispensable over the next years, discuss recently discovered gene expression-based assays and emphasise the difficulties in biomarker development.