Predictive biomarkers for response to therapy in advanced colorectal/rectal adenocarcinoma

Over the past couple of decades, with discovery of novel targeted therapies, and expansion of our understanding of the molecular biology of rectal cancer, there has been an emergence of a wide variety of therapeutic options designed to facilitate a personalized approach for the treatment of this malignancy. A plethora of new prognostic and predictive single genes and proteins are being discovered that may reflect susceptibility and/or resistance to therapy. Pathologic complete response rates occur in 10-16% of patients and have been shown to correlate with both disease-free and overall survival. However, the response to neoadjuvant therapy remains variable and unpredictable. In this review, some of these novel markers are discussed for their potential use as pharmacogenetic predictors for specific therapy, drug toxicity, and disease outcome.