Results revealed that loss of CYLD DNA copy number was detected in NPC-derived cell lines (0.608 ± 0.08 and 0.613 ± 0.073 for individual amplicon, respectively) as well as in primary NPC cell strains (0.852 ± 0.056 and 0.73 ± 0.04) compared to normal nasopharyngeal epithelial cell strains (NPE) or fibroblasts (Fig. 5C, D). The gene discussed is CYLD; the disease is nasopharyngeal carcinoma.