ESR1 and endometrial cancer: PET imaging of endometrial cancer with tracers specific for e.g., hypoxia, cell proliferation, amino acid metabolism, angiogenesis, apoptosis, blood flow, fatty acid metabolism, or estrogen receptors may, however, lead to increased understanding of the biologic processes relevant for tumor progression and metastatic spread in endometrial cancer, and will be particularly interesting to explore as predictive markers sequentially during treatment with targeted and novel therapeutics for early signs of response.