KRAS and NRAS genes mutations as biomarkers in the therapy of colorectal cancer and the basic methods of their detection

Determination of the mutations' status in the KRAS and NRAS genes is a necessary requirement in the treatment of patients with colorectal cancer (CRC). Patients with certain mutations in the KRAS and NRAS genes are resistant to anti-EGFR drug therapy and have a lower median survival rate than those with WT (wild type) genotypes, that indicates a negative prognosis in the case when mutations are present. Currently, there are no registered targeted drugs for carriers of the KRAS and NRAS genes mutations, however, preparations based on small molecules are under way. The gold standard for detecting mutations in the KRAS and NRAS genes is the analysis of the biopsy material in paraffin blocks. However, this method has significant limitations that can be circumvented by the analysis of circulating tumor DNA a promising new method in the diagnosis of colorectal cancer.