GJA1 and neoplasm: More interestingly, both Cx43 osteocyte-specific knockout mice and osteocyte-specific Δ130–136 transgenic mice with impaired Cx43-GJs and Cx43-HCs showed increased tumor growth and an attenuated inhibitory effect of bisphosphonate drugs, whereas R76W transgenic mice with functional Cx43-HCs but not Cx43-GJs in osteocytes did not show significant differences compared to control mice (167).