Epstein-Barr virus infection of sinonasal lymphoepithelial carcinoma in Guangzhou

Objectives To investigate the prevalence of sinonasal lymphoepithelial carc inoma (SNLEC) in Guangzhou, a high incidence area of nasopharyngeal carcino ma (NPC), and to detect whether it is associated with Epstein-Barr virus (E BV) infection. Methods Twenty confirmed SNLEC specimens were collected from all of the sin onasal carcinoma biopsies performed in the 8 years 1989 - 1996 at the Sun Y at-sen University of Medical Sciences. EBV encoded early RNAs were detected by use of in-situ hybridization. A variety of antigens, including the EBV nuclear antigen 1, latent membrane protein 1, BZLF1 protein, diffuse early antigen, viral capsid antigen and membrane antigen, were detected using imm unohistochemistry. Additionally, 36 NPC specimens were used for comparison. Results Twenty SNLECs were identified. Seventeen SNLECs were developed in t he nasal cavity, and 3 in the maxillary sinus. The mean age (46.25 y), male to female ratio (3:1), histopathology and lymphoinfiltration of the 20 SNL ECs were identical with those of the 36 NPCs. Thirteen (65.0%) of the 20 SN LECs showed an expansive growth pattern, while 27 (75.0%) of the 36 NPCs sh owed an infiltrating or mixed growth pattern. The majority of cancer cells in all of the 20 SNLECs showed EBV encoded early RNAs. The EBV nuclear anti gen 1 expression of SNLEC was less intensive than that of NPC. The expressi on rate of latent membrane protein 1 for SNLEC (3/20,15%) was lower than th at for NPC (19/36, 52.8%). The expression rates of BZLF1 protein (2/20, 10. 0%), diffuse early antigen (19/20, 95.0%), viral capsid antigen (15/20, 75. 0%), and membrane antigen (13/20, 65.0%) for SNLEC were higher than those ( 0/36, 0.0%; 31/36, 86.0%; 18/36, 50%; and 14/36, 38.9%) for NPC. Conclusions SNLEC is not uncommon in Guangzhou. This tumour is also consist ently associated with EBV infection like NPC. As compared to NPC, the EBV h arbored in SNLECs seems to express the EBV nuclear antigen 1 weakly and has a lower expression rate of latent membrane protein 1 as well as higher exp ression rates of EBV lytic products.