Genotyping, levels of expression and physical status of human papilloma virus in oropharyngeal squamous cell carcinoma among Colombian patients

Abstract

Introduction: One of the risk factors for squamous cell oropharyngeal carcinoma is infection with the human papilloma virus (HPV), with prevalences that vary depending on the geographical region. Objective: To identify the most frequent HPV viral types in oropharyngeal cancer, the levels of expression and the physical condition of the viral genome. Materials and methods: Forty-six patients were included in the study from among those attending head and neck surgical services in the cities of Bogotá, Manizales and Bucaramanga. In the histopathological report all study samples were characterized as oropharyngeal squamous cell carcinoma. DNA extraction was subsequently performed for HPV genotyping and to determine the physical state of the viral genome, as well as RNA to determine viral transcripts using real-time PCR. Results: HPV prevalence in tumors was 21.74% (n=10) and the most common viral type was HPV-16 (nine cases). Viral expression for HPV-16 was low (one of 11 copies) and the predominant physical state of the virus was mixed (eight cases), with disruption observed at the E1 - E2 binding site (2525 – 3720 nucleotides). Conclusion: The prevalence of HPV associated with oropharyngeal carcinoma among the Colombian study population was 21.7%, which is relatively low. The most frequent viral type was HPV-16, found in a mixed form and with low expression of E7, possibly indicating a poor prognosis for these patients.