Figure 1.

Schematic representation of the validation process of novel biomarkers by using immunohistochemistry. A typical scenario for biomarkers evaluated by immunohistochemistry contemplates that new candidate markers are identified through screen analyses. Then, if commercially available antibodies specific to those markers are found, sections of tissue microarray (TMA) blocks containing a large number of samples are used to prove preliminary results. Whenever a new antibody is used to test a novel biomarker on tissue samples, technical validation is mandatory.