Studies in osteosarcoma, breast and prostate cancer bone metastases have described increased nerve infiltration associated with tumour growth within bone, with blockade of nerve growth factor (NGF) effective to reduce pain indices, despite having no effect on tumour or bone disease11–13, and NGF-related pain in models of breast cancer have also been attributed to sprouting of CGRP+ nerves and formation of localised neuroma12,14. Here, NGF is linked to neoplasm.