The changing role of the pathologist in the era of targeted therapy in personalized medicine

For a long time, the pathologist has mainly been dedicated to the morphological diagnosis, including macroscopic and microscopic examination of organs and tissues. Moreover, interaction between clinicians and pathologists was limited to the morphological diagnostic reports provided by pathologists. Recently, medical science has dramatically changed due to technological progress, recent discoveries in cellular and molecular pathways, the growing sub-specialization in the medical fields, the need to individualize oncological therapies. Indeed, due to the development of an increasingly individualbased therapy, the ‘companion diagnostic,’ specifically analyzing tumor markers able to predict the response of the patients to targeted therapies [1]. Thus, while the previous approach in diagnostic pathology were addressed to define prognostic biomarkers, currently the pathologists are required to identify biomarkers useful to predict patient’s potential response to target drugs [2]. For this reasons, classifications of the diseases, particularly neoplasms, enriched of immunohistochemical and molecular features. In this scenario, the pathologist has gone beyond the morphological diagnosis, definitively entering the patients’ clinical management, and leading the therapeutic addresses. Indeed, pathologists in a synergic collaboration with molecular biologists can provide necessary molecular information useful for a complete diagnosis. Therefore, pathologists become the final certifier of a complex diagnostic process, being medical professionals with the required skills to integrate morphological and molecular information in a report, including diagnosis and predictive biomarkers. This integrated information allows clinicians to choose the best therapeutic procedure for the individual patient (e.g. chemotherapy or immunotherapy or gene therapy) [3].