Genetic variability in E6 and E7 oncogenes of human papillomavirus Type 16 from Congolese cervical cancer isolates

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.

Variants of human papillomaviruses 16 (HPV16) in Uigur women in Xinjiang, China

“…In good agreement with previous reports [ 22 , 33 , 34 ], the current study showed that E7 region was strongly conserved as compared to E6. We found only one mutation A647G (N29S), which is common in Asia women.…”

Performance of OncoE6 cervical test with collection methods enabling self-sampling

“…Congo, Morocco, Romania, China). The mutation we found in our sample set # 5, however, was not described in any of the studies [ 17 – 25 ]. We therefore conclude that this mutation represents a very low frequency mutation and will thus not influence the clinical performance of the OncoE6 Test in the general population, since it is highly unlikely to find this same mutation in relevant numbers elsewhere.…”

Identifikasi Gen E7 Isolat Human Papillomavirus Tipe 18 (HPV18) dari Penderita Kanker Serviks

“…Hasil ini mendukung penelitian yang telah dikerjakan sebelumnya mengenai identifikasi tipe-tipe HPV yang berasal dari kedua rumah sakit tersebut, dimana ditemukan 40,4% merupakan HPV tipe 18 dan 28,5% merupakan HPV tipe 16 [10]. Diperlukan penelitian lebih lanjut terhadap varian gen E7 HPV18 ini, karena beberapa penelitian menyebutkan bahwa varian yang berbeda dari gen E7 HPV18 dapat memberikan aktivitas onkogenik yang berbeda pula terhadap kanker serviks yang ditimbulkannya [11] sehingga nantinya bisa dirancang jenis vaksin yang sesuai untuk penderita kanker serviks di wilayah Sumbar dan Riau khususnya dan Indonesia pada umumya.…”