Cancer pharmacogenomics: implications on ethnic diversity and drug response

The goal of pharmacogenomic research is to discover and validate genetic variants that are predictive of drug response, for eventual implementation into clinical practice. Cancer pharmacogenomics provides the opportunity to analyze two sets of DNA, that of the tumor (somatic) and that of the host (germline). Germline variants are inherited variations and are often associated with the pharmacokinetic behavior of a drug, including drug disposition and ultimately drug efficacy and/or toxicity, whereas somatic mutations are often useful in predicting the pharmacodynamic response to drugs. Pharmacoethnicity, or ethnic diversity in drug response or toxicity, is an increasingly recognized factor accounting for interindividual variations in anticancer drug response. Pharmacoethnicity is often determined by germline pharmacogenomic factors and the distribution of single nucleotide polymorphisms across various populations, but it may also be influenced by nongenetic factors, such as environmental factors. This review aims to elucidate the importance of pharmacoethnicity in cancer pharmacogenomic research and implementation, focusing solely on germline variants.