Breast cancer risk in NF1-deleted patients

Neurofibromatosis type 1 (NF1, OMIM #162200) is a genetic condition with an autosomal dominant transmission. The disorder is caused by loss-of-function variants in NF1. The tumour suppressor gene NF1 (OMIM *613113) encodes neurofibromin, a negative regulator of the RAS-mitogen-activated protein kinase (MAPK) pathway. NF1 is associated with an increased risk of developing malignant tumours, mainly malignant peripheral nerve sheath tumours.1

NF1 women were previously reported to have standardised incidence ratio (SIR) for the development of breast cancer (BC) of 3.5 compared with the general population,2 with an SIR of 11.1 in women aged under 40 years.3 Some NF1 patients were eventually described with bilateral BC,4–8 a poor prognosis condition.9 In a study published in 2019, Frayling et al identified the germline NF1 pathogenic variants in an international cohort of 78 NF1 patients with…