Cancer Over-expressed Receptors as Targets for PET Molecular Imaging

Positron Emission Tomography (PET) is a nuclear §medicine imaging technology which§allows for four-dimensional, quantitative§determination of the distribution of labeled§biological compounds within the human body. The§high sensitivity of PET and the low concentration of§the tracers used, allow quantitative visualization§of low capacity biochemical systems such as§receptors.§Epidermal growth factor receptor (EGFR) is involved §in proliferation, cell movement, §cell survival and differentiation of both normal and §malignant cells. EGFR over-expression has been §detected in a variety of malignant epithelial tumors.§Androgen Receptor (AR) plays a critical role in §initiation and growth of §prostate cancer cells. Nearly 80-90% of prostate §cancers are dependent on androgen at initial §diagnosis.§While EGFR and AR are established targets for §treatment, the clinical outcome in most cases is §suboptimal.§Development of suitable labeled biomarkers that bind §to the EGFR or to the AR may allow the mapping §and quantification of these receptors in cancer in-§vivo, and will lead to monitoring of response to§hormonal or other chemotherapeutic treatment.