In this review, we detail the frequency of somatic NF1 mutations in many non-NF1-associated sporadic cancers including melanoma, glioblastoma, neuroblastoma, breast cancer, ovarian serous carcinoma, paraganglioma and phaeochromocytoma, lung adenocarcinoma, lung squamous cell carcinoma, bladder, colorectal and leukaemia. The gene discussed is NF1; the disease is breast cancer.