To interrogate the impact of NF1 loss in breast cancer, we performed an analysis of the METABRIC breast cancer data set which contained 2,051 patients with clinical annotation including CNV and SNP genotypes.33 In this cohort, there were 43 patients (2.1%) with truncating mutations, including frameshift deletions or insertions, nonsense mutations, and splice site alterations (Fig. 5a). This evidence concerns the gene NF1 and breast cancer.