Receptor tyrosine kinase inhibitors: molecularly targeted drugs for veterinary cancer therapy.

Tyrosine kinases (TKs) are key mediators of signalling pathways in cells. Located at the surface of the cell, within the cytoplasm or in the nucleous, TKs have been showed to be involved in regulation of normal cellular processes and also play an important role in the development, progression and spread of several types of cancer. Seventy percent of TK's are Receptor Tyrosine Kinases and these have become key targets for cancer therapy. This short synopsis is intended to give the reader an introduction to this area of targeted therapy for cancer as a prelude to this special edition of Veterinary and Comparative Oncology.