Epstein-Barr virus DNA is not increased in tonsillar carcinoma

Epstein-Barr virus (EBV) is a known oncogenic virus associated with a wide variety of cancers, including nasopharyngeal carcinoma. Waldeyer's ring, a collection of lymphoid tissues, includes the nasopharynx, pharyngeal, and lingual tonsils. To determine if EBV plays a causative role in carcinomas arising from other tissues in Waldeyer's ring, we examined pharyngeal tonsillar carcinomas for evidence of EBV infection. As previously reported, DNA was extracted from 53 consecutive tonsil cancers, as well as from age- and gender-matched non-cancerous tonsillectomy specimens. Three different sets of primers for discrete exons of EBV were then used to determine if active or latent EBV infection was expressed in the extracted DNA using the polymerase chain reaction (PCR). All positive bands were then sequenced to confirm the presence of amplified EBV fragments. None of the samples showed evidence for active EBV infection. In primers demonstrating latent infection, 1 of 53 (1.9%) of tumors were positive, versus 6 of 53 (11.3%) of the controls. These results indicate that EBV expression is not increased in DNA from tonsil cancers and that EBV infection does not have a causal relationship with tonsil cancer.