In conclusion, our present study suggests that implantation of Walker 256 mammary gland carcinoma cells into the tibia of rats produces a prominent expression of CXCL12/CXCR4 in the spinal cord, which may underlie the activation of these spinal neurons and glial cells as well as hyperalgesic behaviors in bone cancer rats. Here, CXCR4 is linked to bone neoplasm.