When compared with the immortalized nasopharyngeal epithelial cell line, NP69, the protein levels of BRCA1 in all EBV‐positive NPC patient‐derived xenografts and two EBV‐positive NPC cell lines (NPC43, C17 cells) were highly reduced, whereas high BRCA1 expression was detected in the other three NPC cells, two of which were EBV‐negative (HK1 and NPC53). This evidence concerns the gene BRCA1 and nasopharyngeal carcinoma.