Targeted therapy from the point of view of medical oncology

&nbspIn the last few years, targeted therapy has become an integral part of the armamentarium of medical oncology. Targeted agents have been introduced into the treatment of the most common malignant tumors, including breast, colorectal and non-small cell lung carcinoma. The advent of targeted therapy has also changed the course of tumors that were hitherto resistant to any systemic agents, e.g. renal cell carcinoma and gastrointestinal stromal tumors. The term targeted therapy implies a precise knowledge of the target but with some targeted agents the expanding knowledge on tumor biology has so far failed to translate into defining a predictive factor. On the other hand, evidence is emerging that the host immune response may play a crucial role in determining the response to some targeted agents, specifically monoclonal antibodies. Thus, algorithms for the prediction of response to targeted treatment may include not only molecular targets expressed by the tumor cell but also parameters determining the host immune response.