Expression of Epstein-Barr virus-encoded RNA and biological markers in Italian nasopharingeal carcinomas

Nasopharingeal carcinoma (NPC) is frequently associated with Epstein-Barr virus (EBV), but little is known about its pathogenesis in Western countries, where its incidence is low and EBV is not endemic. We studied 26 Italian cases of NPC: 24 of the non-keratinizing subtype, and 2 keratinizing. We used immunohistochemistry to evaluate p53, bcl-2 and Ki-67 protein expression, and in situ hybridization (ISH) to assess bcl-2 mRNA and the EBV transcript, EBER1, with bcl-2 protein and mRNA expression being compared in serial sections. As regards bcl-2, the protein or mRNA was expressed in 15/26 (58%) and 17 (65%) cases respectively, with co-expression being found only in 9 (35%) cases; 23 (88%) cases were positive for one or the other. EBER1 was detected in 17/26 (65%) cases, of which 80% and 71% coexpressed bcl-2 protein or mRNA, respectively. Only 9/26(35%) cases had a high Ki67 proliferative index; 3/26(12%) overexpressed p53. This study of NPC in Italy confirms the importance of EBV and bcl-2 in Western cases. The discrepancy between bcl-2 mRNA and protein expression invites investigation into a possible internal bcl-2 regulation system.