BackgroundThe Linear Array® (LA) genotyping test is one of the most used methodologies for Human papillomavirus (HPV) genotyping, in that it is able to detect 37 HPV genotypes and co-infections in the same sample. However, the assay is limited to a restricted number of HPV, and sequence variations in the detection region of the HPV probes could give false negatives results. Recently, 454 Next-Generation sequencing (NGS) technology has been efficiently used also for HPV genotyping; this methodology is based on massive sequencing of HPV fragments and is expected to be highly specific and sensitive. In this work, we studied HPV prevalence in cervixes of women in Western Mexico by LA and confirmed the genotypes found by NGS.MethodsTwo hundred thirty three cervical samples from women Without cervical lesions (WCL, n = 48), with Cervical intraepithelial neoplasia grade 1 (CIN I, n = 98), or with Cervical cancer (CC, n = 87) were recruited, DNA was extracted, and HPV positivity was determined by PCR amplification using PGMY09/11 primers. All HPV- positive samples were genotyped individually by LA. Additionally, pools of amplicons from the PGMY-PCR products were sequenced using 454 NGS technology. Results obtained by NGS were compared with those of LA for each group of samples.ResultsWe identified 35 HPV genotypes, among which 30 were identified by both technologies; in addition, the HPV genotypes 32, 44, 74, 102 and 114 were detected by NGS. These latter genotypes, to our knowledge, have not been previously reported in Mexican population. Furthermore, we found that LA did not detect, in some diagnosis groups, certain HPV genotypes included in the test, such as 6, 11, 16, 26, 35, 51, 58, 68, 73, and 89, which indicates possible variations at the species level.ConclusionsThere are HPV genotypes in Mexican population that cannot be detected by LA, which is, at present, the most complete commercial genotyping test. More studies are necessary to determine the impact of HPV-44, 74, 102 and 114 on the risk of developing CC. A greater number of samples must be analyzed by NGS for the most accurate determination of Mexican HPV variants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12985-015-0391-4) contains supplementary material, which is available to authorized users.

Background Human papillomavirus infection is an important factor associated with cervical cancer (CC) development. The prevalence and genotype distribution vary greatly worldwide. Examining local epidemiological data constitutes an important step towards the development of vaccines to prevent CC. In this work, we studied the prevalence of HPV genotypes in women from Western Mexico with the COBAS 4800 and/or Linear Array Genotyping Test (LA). Methods The samples analysed in this study represent a population from Western Mexico, which includes six different states. Our approach was first to test for HPV in cervical samples from women who attended their health clinic for routine gynaecological studies (open-population, n = 3000) by utilizing COBAS 4800. Afterwards, 300 of the HPV-positive samples were randomly selected to be genotyped with LA; finally, we genotyped samples from women with cervical intraepithelial neoplasia grade 1 (CIN 1, n = 71) and CC (n = 96) with LA. Sociodemographic data of the diverse groups were also compared. Results The overall HPV prevalence among the open-population of women as determined by COBAS 4800 was 12.1% (n = 364/3000). Among the HPV-positive samples, single infections (SI) with HPV16 were detected in 12.4% (n = 45/364), SI with HPV18 were detected in 1.4%, and infection with at least one of the genotypes included in the high-risk HPV pool was detected in 74.5% of the cases. LA analysis of the samples showed that in addition to HPV genotypes 16 and 18, there was a high prevalence of HPV genotypes 59, 66, 52, 51, 39 and 56 in women from Western Mexico. With respect to the sociodemographic data, we found statistically significant differences in the number of pregnancies, the use of hormonal contraceptives and tobacco intake. Conclusions Our data indicate that there is a high prevalence of HPV genotypes which are not covered by the vaccines currently available in Mexico; therefore, it is necessary to include HPVs 59, 66, 51, 39 and 56 in the design of future vaccines to reduce the risk of CC development. It is also essential to emphasize that the use of hormonal contraceptives and tobacco smoking are risk factors for CC development in addition to the presence of HPV.

Background: Cervical cancer (CC) is associated to high-risk human papillomavirus (HPV) infections, for this reason it is crucial to have sensitive and accurate HPV diagnostic tests. To date, most research is focused on HPVs within the Alphapapillomavirus (α-PVs) genus and little attention has been paid to cervical infections with other HPV genotypes, like those of the Betapapillomavirus (β-PVs) and Gammapapillomavirus (γ-PVs) genera. The aim of this study was to determine the HPV genotypes from different genera in women with CC using Next-Generation Sequencing (NGS). Methods: The study comprised 48 HPV positive CC samples evaluated with the Linear Array HPV Genotyping test and individually sequenced by 454 NGS using PGMY09/11 and FAP primers. To determine the HPV genotypes present in each sample, the obtained sequences were compared with all HPV L1 gene reference sequences from the Papillomavirus Episteme database (PaVE). Moreover, 50 HPV positive low-grade cervical lesion samples individually genotyped with NGS were also included to determine the genotypes present preferentially in CC patients.

BackgroundDiffuse gastric cancer (DGC) is associated with the reduction or absence of the expression of the cell adhesion protein E-cadherin (encoded by the CDH1 gene). Molecular characteristics are less well described for mixed gastric cancer (MGC). The main somatic alterations that have been described in the CDH1 gene are mutations, loss of heterozygosity (LOH) and promoter methylation. The aim was to analyze CDH1 somatic alterations in Mexican patients with diffuse and mixed gastric cancer.MethodsWe searched for mutations in the CDH1 gene in tumor DNA from DGC (n = 13) and MGC (n = 7) patients by next generation sequencing (NGS). Validation of findings was performed using Sanger sequencing. LOH was analyzed using dinucleotide repeat markers surrounding the CDH1 gene, and methylation was investigated by DNA bisulfite conversion and sequencing. E-cadherin protein deficiency was analyzed by immunohistochemistry.ResultsSeventeen point variants were identified by NGS, 13 of them were validated by Sanger sequencing. Only 1/13 had not been previously reported (c.-137C > A), and 12/13 were already reported as polymorphisms. Two DGC cases presented LOH at the locus 16q22.1 (13.3%). CDH1 promoter methylation was positive in (7/11) 63.6% and (4/6) 66.6% of the cases with DGC and MGC, respectively. E-cadherin protein deficiency was observed in 58.3% of DGC cases while 100% in MGC cases.ConclusionsWhile no pathogenic somatic mutations were found that could explain the diffuse histology of gastric cancer in DGC and MGC, methylation was the most common somatic inactivation event of the CDH1 gene, and LOH was rare. The previously unreported c.-137C > A variant modify the CDH1 gene expression since it alters the binding sites for transcription factors.Electronic supplementary materialThe online version of this article (10.1186/s12885-019-5294-0) contains supplementary material, which is available to authorized users.