Some preliminary results of the phase II clinical trial, investigating the evaluation of the diagnostic, prognostic and follow-up potential of [18F]F-4FMFES PET imaging for ER-positive advanced BCas, have shown that [18F]F-4FMFES PET achieves a lower non-specific signal and better tumor contrast than [18F]FES PET, resulting in improved diagnostic confidence and lower false-negative rates (NCT04824014) [20]. The gene discussed is ESR1; the disease is neoplasm.