Variabilidad genética del gen E6, virus del papiloma humano genotipo 16 en muestras aisladas en el Ecuador

Abstract

Human papillomavirus (HPV) infection is caused by papillomaviruses, which are responsible for cervical cancer—one of the most common cancers worldwide. For this study, the E6 sequence of genotype 16 was analyzed; this HPV genotype is classified as high-risk for causing cervical cancer. The E6 gene is frequently used in phylogenetic studies; it is employed alongside the Long Control Region (LCR) to distinguish lineages and alongside the E7 gene to assess the oncogenic potential of the samples. Specific primers for the E6 gene were used in the study, yielding a 220-bp amplicon; these primers were designed at the laboratory of the National Institute of Public Health and Research of Ecuador. A total of 15 samples were used, and the methodology allowed for the analysis of 7 samples that yielded high-quality sequencing chromatograms. Phylogenetic analysis was performed using the BEAST 1.8.4 software with the Neighbor-Joining method and the Jukes-Cantor model (this parameter was selected based on a prior study conducted using MEGA 5.2 software). The results identified the lineages circulating in the country: African (28%), European (28%), and Asian-American (44%), with the latter showing the highest prevalence among the analyzed samples. The Asian-American lineage exhibits higher oncogenic potential compared to other lineages of the same genotype. This finding serves as a warning for the Ministry of Public Health, as it suggests future cancer cases in the country; the fact that HPV infection is often asymptomatic further exacerbates the problem. This study aims to observe the genetic variability present in the country in order to track how the disease is mutating and identify the most predominant lineages.