Turkiye Klinikleri Journal of Medical Sciences, cilt.30, sa.3 SUPPL., 2010 (SCI-Expanded)
There is wide variability in the response of individuals to standard doses of drug therapy. This is an important problem in clinical practice, where it can lead to therapeutic failures or adverse drug events. Polymorphisms in genes coding for metabolizing enzymes and drug transporters can affect drug efficacy and toxicity. Pharmacogenetics is the study of inherited differences in interindividual drug metabolism and effects, with the aim to select the optimal drug and dosage for patients. Pharmacogenetics is especially important for oncology, because systemic toxicity and unpredictable efficacy commonly occur in cancer therapies. Genetic polymorphisms in drug metabolizing enzymes and transporter molecules are responsible for much of the interindividual differences in the response of many chemotherapy agents. There are also genetic polymorphisms in drug targets that have been shown to influence drug response. Large scale clinical trials demonstrated that pharmacogenetic testing in the clinical setting can improve the benefit/risk ratio of drug therapy. However, complexities in pharmacogenenetics should be understood before individualized therapy can be applied on a routine basis. This review focuses on the clinical significance of polymorphisms in drug-metabolizing enzymes, transporters and target molecules in influencing efficacy and toxicity of anticancer therapy. © 2010 by Türkiye Klinikleri.