However, a short-term reduction of FDG and [11C]-MET uptake (after 7 and 14 days of treatment) was clearly observed in the MC7-L1 ER+ tumor when using fulvestrant or letrozole treatment compared to the control group (with the exception of letrozole followed by FDG at day 14, where a non-significant reduction was observed). This evidence concerns the gene SMUG1 and neoplasm.