Cervical cancer is the second leading type of neoplasia in Mexican women and high risk HPV has been associated with its development[1, 2]. Variations in HPV genomes have been associated with the severity of cervical lesions [3, 4]. We determined genetic variations founded in L1 region from different HPV types isolated from northeastern Mexican patients and compared them with the results obtained with real time PCR genotyping kit.
We collected 255 cervical samples from patients who attended colposcopy consultation at the Hospital Universitario “Dr. Jose Eleuterio Gonzalez” of the Universidad Autónoma de Nuevo León in Monterrey, Nuevo Leon, Mexico. One hundred forty-one samples were HPV positive, and genotyped using the E. coli Amplisens HPV HRC Genotype titre FRT kit using the AB7500 Fast Real Time PCR. We detected 43 HPV monoinfected samples and amplified the L1 region using PGMY 09/11 primers and sequenced the PCR product. The obtained sequences were assembled, and posteriorly analyzed with MEGA7. We built a phylogenetic tree with the maximum likelihood method using the GTR +G model [4, 5].
The most frequent HPV was HPV 52. Seventy percent of our samples were infected with more than one HPV type. We identified 43 HPV strains from Mexican patients, were the 14% of those patients had a persistent HPV infection. Most of the patients (41%) presented a clinically valuable viral load. These strains had different genetic variations in the L1 region, and most of them were synonymous. There was no significant association of the detected HPV type with the viral load. Twenty HPV sequences differed from the HPV detected by real-time PCR.
The discrepancy between the HPV type detected by real-time PCR and Sanger sequencing was high [6]. This could be due to coinfections with several HPV types, with higher viral loads. We speculate that the included HPV probes cross-react with other HPVs not included in the kit [7]. Due to the samples background and the high frequency of the HPV coinfections in our population, there is a need to isolate HPV strains to evaluate their carcinogenic potential and the genetic evolution of these viruses circulating in the northeastern region. Even if their viral load was not associated with the HPV type, the genetic variations found could explain the carcinogenic potential these strains might have.
1. INEGI Instituto Nacional de Estadística y Geografía. Available at: http://www.inegi.org.mx/default.aspx
2. OMS | Salud de la mujer. WHO. 2013. doi: /entity/mediacentre/factsheets/fs334/es/index.html.
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4. King AJ, Sonsma JA, Vriend HJ, van der Sande MA, Feltkamp MC, Boot HJ, et al. Genetic Diversity in the Major Capsid L1 Protein of HPV-16 and HPV-18 in the Netherlands. PLoS One. 2016;11(4):e0152782. Epub 2016/04/14. doi: 10.1371/journal.pone.0152782. PubMed PMID: 27070907; PubMed Central PMCID: PMCPMC4829201.
5. Ferenczi A, Gyongyosi E, Szalmas A, Laszlo B, Konya J, Veress G. Phylogenetic and functional analysis of sequence variation of human papillomavirus type 31 E6 and E7 oncoproteins. Infect Genet Evol. 2016;43:94-100. Epub 2016/05/20. doi: 10.1016/j.meegid.2016.05.020. PubMed PMID: 27197052.
6. Wong OG, Lo CK, Chow JN, Tsun OK, Szeto E, Liu SS, et al. Comparison of the GenoFlow human papillomavirus (HPV) test and the Linear Array assay for HPV screening in an Asian population. J Clin Microbiol. 2012;50(5):1691-7. Epub 2012/02/18. doi: 10.1128/jcm.05933-11. PubMed PMID: 22337983; PubMed Central PMCID: PMCPMC3347143.
7. Ostrbenk A, Kocjan BJ, Poljak M. Specificity of the Linear Array HPV Genotyping Test for detecting human papillomavirus genotype 52 (HPV-52). Acta Dermatovenerol Alp Pannonica Adriat. 2014;23(3):53-6. Epub 2014/09/23. PubMed PMID: 25242161.