While there is currently no gold standard non-invasive diagnostic assay for identifying GR-expressing tumors, the tumor-autonomous expression of other nuclear hormone receptors within the same subfamily (e.g. AR, ER, progesterone receptor [PR]) has been successfully detected in patients with radiolabeled agonists and positron emission tomography (PET) [16–18]. This evidence concerns the gene NR3C1 and neoplasm.