Pharmacogenetics and biomarkers in colorectal cancer.

The prognosis of patients with colorectal cancer (CRC) is affected by various factors at the time of diagnosis, including location of the tumor, gender, age and overall performance status of the patient. Predicting response and limiting drug-induced toxicity for patients with CRC are also critical. Interpatient differences in tumor response and drug toxicity are common during chemotherapy. Genomic variability of key metabolic enzyme complexes, drug targets and drug transport molecules are important contributing factors. At present, there is inconsistent and rather low use of pharmacogenetic testing in the clinical setting because of a lack of robust evidence or of resources. Patients' selection and tailored treatments by the introduction of genetic testing will hopefully allow better response prediction and limit drug-induced toxicity leading to improved patient outcomes in the most cost-effective way. Here, we review the main genetic alterations observed in familial and sporadic CRC and their associations with the metabolism, efficacy and toxicities of drugs used in this disease.