Molecular predictive factors of response to anti-EGFR antibodies in colorectal cancer patients

Monoclonal antibodies against EGFR represent one of the most important recent advancements in the treatment of colorectal cancer. Anyway, to date, only a subset of patients can really take advantage from this kind of drugs. The identification of predictive factors that are able to stratify patients who potentially can benefit by these biological treatment, is an important aim of anticancer research both in clinical and in pre-clinical fields. Many studies evaluating classical IHC analysis of protein expression failed in this purpose. So in the last years there was the need to look forward to a new class of molecular predictive factors. Indeed a number of biomarkers have been evaluated in their potential to predict the response to anti-EGFR-based therapies. These include marker related to EGFR amplification, activation and phosphorylation, EGFR polymorphisms, but also markers related to Ras/Raf/MAPK and the PI3K/Akt signalling pathways and angiogenesis. This review will focus the attention to these new genetic and molecular markers.