Clinical implication of immunohistochemical markers

The role of the pathologist is to establish accurate diagnosis more and more with the help of complementary techniques. At present immunohistochemical expression of some diagnostic and prognostic factors may possibly predict the response to specific therapies. We focus here on the expression of three of these markers: epidermal growth factor receptor which overexpression is correlated with aggressive tumoral behaviour and with the possibility of a targeted therapy, cytokeratins 7 and 20 with their diagnostic implication in carcinomatous differentiation, and we close this review with the identification of markers related to hereditary non-polyposis colorectal cancer involving microsatellite instability.