Sequence Variations of Human Papillomavirus Type 16 E6 and E7 Genes in Cervical Cancer Isolates from Gabon
Samira Zoa Assoumou
Laboratoire de Virologie, Microbiologie et Qualité/ETB, Faculté des Sciences et Techniques de Mohammedia, Université Hassan II Casablanca, B.P. 146, Mohammedia 20650, Maroc and Laboratoire d’Agroalimentaire et Santé, Département de Biologie Appliquée, Faculté des Sciences et Techniques, Université Hassan 1Er Settat, B.P. 577 Settat, Maroc.
Luc Magloire Anicet Boumba
Laboratoire de Virologie, Microbiologie et Qualité/ETB, Faculté des Sciences et Techniques de Mohammedia, Université Hassan II Casablanca, B.P. 146, Mohammedia 20650, Maroc and Laboratoire d’Agroalimentaire et Santé, Département de Biologie Appliquée, Faculté des Sciences et Techniques, Université Hassan 1Er Settat, B.P. 577 Settat, Maroc.
Angelique Ndjoyi Mbiguino
Laboratoire de référence MST/Sida, Laboratoire de Référence Rougeole, Rubéole et Fièvre Jaune, Département de Bactériologie et Virologie, Faculté de Médecine et des Sciences de la Santé, Université des Sciences de la Santé, Libreville, Gabon.
Barthelemy Mabika Mabika
Département d’Anatomie et de Cytologie Pathologiques, Faculté de Médecine et des Sciences de la Santé, Université des Sciences de la Santé, Libreville, Gabon.
Ernest Belembaogo
Institut de Cancérologie d’Agondjé, Libreville, Gabon.
Abdelkrim Khattabi
Laboratoire d’Agroalimentaire et Santé, Département de Biologie Appliquée, Faculté des Sciences et Techniques, Université Hassan 1Er Settat, B.P. 577 Settat, Maroc.
Moulay Mustapha Ennaji *
Laboratoire de Virologie, Microbiologie et Qualité/ETB, Faculté des Sciences et Techniques de Mohammedia, Université Hassan II Casablanca, B.P. 146, Mohammedia 20650, Maroc.
*Author to whom correspondence should be addressed.
Abstract
Aims: HPV-16 variants distribution is reported to differ geographically and in their oncogenic potential for progression to cervical cancer. In this study, we investigated the HPV 16 variants distribution among women from Gabon.
Methodology: Amplification of E6 and E7 genes of 29 HPV-16 isolates was performed by using type-specific primers PCR and then directly sequenced. The sequences obtained were aligned with the HPV-16 GenBank reference sequences.
Results: Out of the 29 samples investigated, 25 were successfully amplified. In the 25 samples analyzed 9 and 3 nucleotide changes in E6 and E7 gene respectively were found. In the E6 gene, the most frequently observed mutation were C143G, G145T, T286A, A289G, C335T which led Q14D and H78Y non- synonymous amino acid variations. The others mutations found C109T; G132C; G132T; A403G were detected in 24% (6 of 25), 68% (17 of 25), 32% (8 of 25), 32% (8 of 25) respectively. The E7 gene appears to be better conserved than the E6 gene. Only 3 mutations were detected of which two were silent: T789C and T795G and the third A647G was missense mutation with substitution of Asparagine to Serine (N29S). This mutation was present in 32% (8 of 25) samples. All the variants detected in this study belonged to the Af1 (68%; 17 of 25) and Af2 (32%; 8 of 25) lineages
Conclusion: This study reported for the first time the distribution of HPV-16 E6 and E7 genetic variants in cervical cancer cases in Gabon. Our results highlight the predominance of African lineage in Gabonese population.
Keywords: HPV 16 variants, E6gene, E7 gene, cervical cancer, Gabon