Several target genes of endogenous opioid system (POMC, PENK and MOR), apoptosis-related genes (Xiap, Smac, Bim, NF-κB and p53), and the neurokinin receptor 1 (NK1R) gene were detected to explore the potential molecular mechanisms involved in our leukemia bone cancer pain. This evidence concerns the gene TACR1 and bone neoplasm.