Phylogeny and Classification of Human Papillomavirus (HPV)16 and HPV18 Variants Based on E6 and L1 genes in Tunisian Women with Cervical Lesions

摘要

Background: High-risk human papillomavirus (HPV) types are the main etiological factors for cervical cancer.HPV16 and HPV18 are generally the most common forms associated with development of high-grade cervical lesions.This study was undertaken to identify intratypic variants of HPV16 and HPV18 among women with cervical lesionsin Tunisia. Materials and Methods: DNA was extracted from cervical samples collected from 49 women. using aPureLinkTM Genomic DNA mini Kit (Invitrogen). E6 and L1 open reading frames (ORF) were amplified by PCRand viral DNA amplicons were subjected to automated sequencing using Big Dye Terminators technology (AppliedBiosystems). The obtained sequences were analyzed using an appropriate software program to allow phylogenetictrees to be generated. Results: HPV16 and HPV18 were detected in 15 and 5 cases, respectively. HPV16 E6 sequencesclustered with the European German lineage (A2) whereas one isolate diverged differently in the L1 region andclustered with the African sub-lineage (B1). HPV 18 E6 sequences clustered with the European sub-lineage (A1)but L1 sequences clustered as a new clade which diverged from A1-A5. Conclusions: Our results suggest that thedistribution of HPV16 and HPV18 sequences in women with cervical lesions in Tunisia is mainly related to Europeanepidemiological conditions and point to the presence of recombinant HPV forms.