CNR1 and neoplasm: Owing to the multi-factorial nature of bone—tumour—sensory nerve cell interactions and crosstalk in the skeleton19,20,61–63 and disparity in receptor expression among these cells, there is an urgent need for examining of the mechanism(s) by which CB1/2 receptor ligands affect the initiation and progression of bone pain, and understanding of the downstream signal transduction pathways and biological and pathological functions and processes involved64–71.