16α-[18F]-fluoro-17ß-oestradiol ([18F]FES): A biomarker for imaging oestrogen receptor expression with positron emission tomography (PET)

Abstract Oestrogens play a major role in the development of gynaecological oestrogen-dependent diseases that overexpress oestrogen receptors (ER+). The ER status is assessed using immunohistochemistry analysis of tissues samples. It is believed that a non-invasive method such as positron emission tomography (PET) that would accurately evaluate and quantify in vivo the presence of ER could play an important role in managing such diseases. PET using fluorinated oestrogen analogues may be helpful in selecting patients who will benefit from endocrine therapy or could be used to identify high-grade cancer with poorer prognosis. Among more than 20 fluorinated oestrogens analogues that have been proposed as PET tracer candidates, 16α-[ 18 F]fluoro-17β-oestradiol ([ 18 F]FES) has been the most actively investigated in preclinical and clinical studies.