Oestrogen-receptor-positive breast tumours harbouring a sporadic NF1 mutation have a poor outcome,90 and depletion of oestrogen through ovariectomy in a NF1-loss-driven rat model of breast cancer leads to tumour regression.91 Breast cancer patients with NF1 sporadic mutations treated with the oestrogen-receptor antagonist fulvestrant showed a good outcome,92 suggesting the potential use of fulvestrant in the context of NF1 patients. This evidence concerns the gene NF1 and breast neoplasm.