CXCL8 and intervertebral disk degenerative disorder: Five of these genes were significantly highly expressed in IDD: CDKN2B (p < 0.05), CDKN2C (p < 0.01), CXCL8 (p < 0.01), MAP4K4 (p < 0.001), and MDM2 (p < 0.05).