Prevalence of human papillomavirus infection and phylogenetic analysis of HPV-16 E6 variants among infected women from Northern Brazil

Abstract

Background: The main cause of cervical cancer in the world is high risks human papillomavirus infection (mainlyrepresented by HPV-16 and HPV-18), that are associated to the development of malign transformation of the epithelium. HPV prevalence exhibits a wide geographical variability and HPV-16 variants have been related to an increased risk of developing cervical intraepithelial lesion. The aim of this study was to describe DNA-HPV prevalence and HPV-16 variants among a women population from Northern Brazil. Methods: One hundred and forty three women, during routine cervical cancer screening, at Juruti Project, fulfilled an epidemiological inquiry and were screened through a molecular HPV test. HPV-16 variants were determined by sequencing the HPV-16 E6 open reading frame. Results: Forty two samples were considered HPV positive (29.4 per cent). None of those had abnormal cytology results. HPV prevalence varied between different age groups (Z(U) = 14.62; p = >0.0001) and high-risk HPVs were more frequent among younger ages. The most prevalent type was HPV-16 (14 per cent) and it variants were classified, predominantly, as European (87.5 per cent). Conclusions: HPV prevalence in our population was higher than described by others and the most prevalent HPV types were high-risk HPVs. The European HPV-16 variant was the most prevalent among HPV-16 positive samples. Our study reinforces the fact that women with normal cytology and a positive molecular test for high-risk HPVs should be submitted to continuous follow up, in order to verify persistence of infection, promoting an early diagnosis of cervical cancer and/or its precursors.