Department of Gynaecology and Obstetrics, University Hospital, Copenhagen, Denmark.
The polymerase chain reaction was used to examine paraffin-embedded tissues of 37 nasopharyngeal carcinomas (NPC) for Epstein-Barr virus (EBV) genomic sequences. EBV DNA was found in 2/14 keratinising squamous cell (WHO 1) carcinomas and in all of 23 non-keratinising and undifferentiated (WHO 2 and 3) NPC. The study confirms the infrequent association of keratinising NPC and EBV, in contrast with the 100% association of the less differentiated NPCs and the virus. The results may indicate a different carcinogenesis for the WHO 1 NPC subtype.