Targeted therapies: the rare cancer paradigm.

This review analyzes the state of the art of targeted therapies for several tumors, starting from the paradigmatic example of Imatinib treatment in chronic myelogenous leukemia (CML). We discuss how rare tumors can be models for various mechanisms of receptor tyrosine kinase (RTK) activation, and provide the opportunity to develop new therapies also for more common cancer types. We discuss the activation of the downstream RTK effectors as further targets for therapies in colorectal cancer. Finally, we highlight how a novel multidimensional approach which adds an in silico dimension to the in vitro and in vivo approach, can predict clinical results.