We examined the expression of BTK, CD72, PTPN6, and VAV1 in NPC cell lines by qRT-PCR, and the expression levels of BTK, CD72, PTPN6, and VAV11 were lower in human nasopharyngeal carcinoma SUNE-1 cells compared with human nasopharyngeal epithelial cells NP69 (P<0.05) (Figure 6). Here, CD72 is linked to nasopharyngeal carcinoma.