Type 73 human papillomavirus in esophageal squamous cell carcinoma: a novel association

Human papillomaviruses (HPVs) commonly cause proliferative lesions of squamous epithelia, and infection with certain HPV types carries a high risk of malignant transformation, especially in the uterine cervix but also at other sites, including the esophagus. We used molecular techniques to detect and type HPV in an in situ squamous cell carcinoma in the esophagus of a 39-year old woman.

DNA was extracted from paraffin sections of the esophageal lesion and of the uterine cervix (which was removed several years earlier), and analyzed for HPV by polymerase chain reaction (PCR). Primers complementary to highly conserved regions of the open reading frame of most genital HPVs were used to amplify a approximately 450 base pair product that contained both conserved and divergent regions. The PCR products were hybridized with probes specific for HPV-6, HPV-11, HPV-16, and HPV-18, and with a consensus probe. A conspicuous band in the esophageal sample failed to hybridize with any of the probes. The amplimer was subcloned and sequenced. The sequence was compared with other known HPVs.

The intraepithelial neoplasia in the patient's cervical cone biopsy contained HPV-16. The esophageal lesion contained HPV that did not hybridize with probes for types 6, 11, 16, or 18, but exhibited 98.3% homology with HPV-73.

Squamous cell carcinoma in situ of the esophagus may be associated with infection by HPV-73.