ESR1 and breast carcinoma: Mortimer et al. [62] studied this metabolic effect with FDG-PET and 16 alpha-[29]fluoroestradiol-17 beta (FES)-PET in 40 women with biopsy-proved advanced ER-positive breast cancer receiving therapy with tamoxifen and concluded that this flare effect could be an indicator of hormone responsiveness in advanced breast cancer.