HHV-6 antigen and viral DNA detected in cervical cells from archived tissue using histochemical staining and hybridization

Abstract

Background: Human herpesvirus type 6 (HHV-6), an ubiquitous virus, is the causative agent for exanthem subitum. The virus is frequently associated with lymphoproliferative disorders and other diseases. Recently, we have reported the frequent presence of HHV-6 in oral carcinoma and the present study extends the observation to cervical carcinoma. Objective: To examine the presence of HHV-6 in cervical carcinoma. Study design: Formalin-fixed, paraffin-embedded cervical carcinoma tissues were examined for the presence of HHV-6 by immunohistochemistry using two monoclonal antibodies that react to HHV-6-encoded p41/38 and gp 116/64/54. In situ hybridization with variant-specific probes were used to type the HHV-6 DNA sequences present. Results: A total of 14/26 (53.9%) carcinoma tissue specimens and 5/8 (62.5%) normal tissue specimens were positive for viral antigens. In situ hybridization studies revealed the presence of HHV-6 DNA sequences in 10/26 (38.5%) carcinoma tissue specimens and 1/8 (12.5%) normal tissue specimens. In the normal tissue, the HHV-6 was present in the endocervical ciliated columnar-epithelial cells and some cells in the subepithelial mucosa but in the carcinoma, the transformed cells were positive for the virus. Conclusion: HHV-6 viral proteins and DNA were found in more than one third of the cervical tissue examined suggesting possible viral expression in these tumours. The significance of the distribution and role of the HHV-6 in cervical tissue remains unclear. Since HHV-6 has an oncogenic potential, the virus may cooperate with other transforming agents for the progression of the disease.