CUL4A and nasopharyngeal carcinoma: Finally, Cox multivariate analysis determined that CUL4A expression (OS: P = .016; PFS: P = .022), as well as primary tumor (both P < .001), nodal status (OS: P = .002; PFS: P = .005) and distant metastasis (OS: P = .012; PFS: P = .017) were independent factors with prognostic value in patients with NPC (Table 2).