Tailoring chemotherapy in advanced colorectal cancer.

In this post-genomic era, the individualization of chemotherapy through the study of pharmacogenetics is becoming an ever attainable reality. Keys to individual variations in drug response and toxicity are being identified through the study of drug targets, metabolizing enzymes, efflux and DNA repair systems at the genomic, mRNA and protein levels. Several promising pharmacogenetic candidates with predictive and/or prognostic value have been identified. These candidates, along with others yet to be identified, could in the near future allow for the tailoring of therapy with an ever increasing chemotherapeutic armamentarium. Well-designed and large prospective analyses, which include relevant pharmacogenetic parameters, are needed to confirm the initial clinical associations reported thus far.