Detection of Epstein-Barr Virus DNA in well and poorly differentiated nasopharyngeal carcinoma cell lines.

Undifferentiated and poorly differentiated nasopharyngeal carcinoma (NPC) were known to be tightly associated with Epstein-Barr Virus (EBV). Its association with well differentiated NPC was also reported. In the present study, the presence of EBV was investigated by nucleic acid hybridization, Polymerase Chain Reaction (PCR), Immunoblot and in situ hybridization in two well differentiated NPC cell lines (CNE-1 and HK-1) and two other poorly differentiated NPC cell line (CNE-2 and CNE-3). Contrary to previous report indicating the absence of EBV in these cell lines, EBV DNA and proteins were present in all cell lines. The detection of EBV became more easily when the investigation was carried out on the nude mice tumor induced by transplantation of each NPC epithelial cell line. The EBV latent membrane protein (LMP1) was found by in situ hybridization to be integrated partly in the chromosomal DNA of these cell lines. The observations indicate that EBV could persist for a long time in the carcinoma cells established directly from well and poorly differentiated tumor biopsies and from transplantable NPC tumor in nude mice.