Epstein-Barr Virus and p53 in Laryngeal and Nasopharyngeal Carcinomas

ABSTRACT

To investigate the correlation between EBV infection and p53 overexpression in laryngeal carcinomas (LC) and nasopharyngeal carcinomas (NPC) in Korea, we analyzed 37 laryngeal squamous cell carcinomas and 33 nasopharyngeal (11 squamous cell and 22 undifferentiated) carcinomas. We used the immunohistochemistry and polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) for p53 overexpression and p53 gene mutation, respectively, and EBER-1 in situ hybridization and PCR using primer for EBNA-1 and EBNA-2 type 1 and 2 for prevalence and the subtype of EBV. The results were as follows; 1) The p53 expression was found in 43.2% of squamous cell LCs, in 54.6% of squamous cell NPCs and in 22.7% of undifferentiated NPCs. The p53 gene mutation was detected in 6 of 23 squamous cell LCs and 3 of 14 undifferentiated NPCs. 2) EBV was detected more frequently in undifferentiated NPCs (95.5%) than in squamous cell NPCs (63.6%) and squamous cell LCs (37.0%). Only type 1 was found in squamous cell LCs and NPCs, whereas both type 1 and type 2 were detected in undifferentiated NPCs. 3) There was no difference according to EBV infection (EBV+ ; 7 cases, EBV- ; 7 cases) in the cases with p53 protein overexpression but mutaion. From the above results, it can be concluded that squamous cell LCs and NPCs are associated with both p53 and EBV, whereas undifferentiated NPCs are more closely associated with EBV than p53. In Korea, both type 1 and 2 are detected in undifferentiated NPCs. Also, our result suggests that EBV infection does not seem to contribute to p53 overexpression. The interrelationship between EBV infection and p53 remains to be further defined.