Abstract
BackgroundThe molecular epidemiological studies showed that some variants of HPV-16, distributed geographically, would present a higher risk of causing cervical cancer. This study aimed to analyze nucleotide changes of HPV-16 E6 and E7 genomic regions from infected Southwestern Congolese women.MethodsDNA of twenty HPV-16 isolates was analyzed by amplifying the E6 and E7 genes using type-specific primers PCR and direct sequencing. The sequences obtained were aligned with the HPV-16 GenBank reference sequences.ResultsThirteen (65.0%) out of 20 DNA-samples were successfully amplified. Genetic analysis revealed 18 and 4 nucleotide changes in E6 and E7 genomic regions respectively. The most frequently observed nucleotide variations were the missense C143G, G145T and C335T in E6 (100%), leading to the non-synonymous amino acid variation Q14D and H78Y. E7 genomic region was found to be highly conserved with two most common T789C and T795G (100%) silent variations. All HPV-16 variants identified belonged to the African lineage: 7 (53.8%) belonged to Af-1 lineage and 6 (46.1%) to Af-2 lineage. The missense mutation G622A (D21N) in the E7 region seems to be described for the first time in this study.ConclusionThis study reported for the first time the distribution of HPV-16 E6 and E7 genetic variants in infected women from southwest Congo. The findings confirmed almost ascendancy of the African lineage in our study population.
Highlights
The molecular epidemiological studies showed that some variants of human papillomaviruses (HPV)-16, distributed geographically, would present a higher risk of causing cervical cancer
Epidemiological and molecular studies are showed that High-risk human papillomaviruses (HPV) types are the etiological agents of cervical cancer [2,3]
Out of 20 HPV-16 single infected cervical cancer samples examined in this study, the E6 and E7 genes were able to be amplified and sequenced in 13 (13/20, 65.0%) DNA samples
Summary
The molecular epidemiological studies showed that some variants of HPV-16, distributed geographically, would present a higher risk of causing cervical cancer. Epidemiological and molecular studies are showed that High-risk human papillomaviruses (HPV) types are the etiological agents of cervical cancer [2,3]. HPV-16 is the most HPV infections resolve spontaneously, suggesting that other co-factors are necessary in the persistence and lesion progression to cancer. These cofactors include some variants of high-risk types such as those of HPV16. Several molecular variants were described and classified according to geographical regions for the HPV-16 genotype [5,6]. The variants have been classified in six major phylogenetic lineages (European, E; Asian, As; African-1, Af-1; African-2, Af-2; Boumba et al Infectious Agents and Cancer (2015) 10:15
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