ObjectivesTo compare and describe type-specific characteristics of HPV16, HPV18 and HPV45 in cervical cancer with respect to 3′LCR methylation and disruption of E1/E2.MethodsThe methylation level of 137 cervical cancer samples (70 with HPV16, 37 with HPV18, and 30 with HPV45) of Brazilian patients was analyzed by pyrosequencing. PCR amplifications were performed to characterize E1 and E2 disruption as an episomal surrogate.ResultsThe 3′LCR of HPV16 showed a higher methylation at all CpG sites (7%, 9%, 11%, 10% and 10%) than homologous HPV18 regions (4%, 5%. 6%, 9% and 5%) and HPV45 regions (7%, 7% and 5%). Presence of intact E1/E2 was associated with higher HPV16 and HPV18 methylation levels at all CpG sites (p < 0.05). Disruption of E1/E2 was more frequently found in HPV45 (97%) and HPV18 (84%) than in HPV16 DNA (30%). HPV16 disruption was more frequently found in E1 (48%) unlike HPV18, where it was found in E2 (61%). Concomitant disruption of E1/E2 was most frequent in HPV45 (72%).ConclusionsThe findings showed a higher methylation associated with intact E1/E2 for HPV16 and HPV18. The closely phylogenetic related HPV18 and HPV45 share a similar methylation level and the frequency of viral genome disruption.

In Brazil, most studies of intra-type variants of human papillomavirus (HPV) have focused on HPV16 and HPV18, but other high-risk HPV types have not been studied. Here, we report the prevalence of lineages and variants of HPV35, HPV45 and HPV58 in cervical cancers from the Amazonian and Southeast Brazilian regions. The most frequent sublineages were A1 for HPV35, B2 for HPV45, and A2 for HPV58. The Southeast region had a higher frequency of the B2 sublineage of HPV45, and for HPV35, the genetic and nucleotide sequence diversity were higher in the Southeast region, suggesting that regional factors are influencing the diversity and lineage prevalence.

The APOBEC3 (A3) proteins are cytidine deaminases that exhibit the ability to insert mutations in DNA and/or RNA sequences. APOBEC3B (A3B) has been evidenced as a DNA mutagen with consistent high expression in several cancer types. Data concerning the A3B influence on HPV infection and cervical cancer are limited and controversial. We investigated the role of A3B expression levels in cervical cancer in affected women positive for infection by different HPV types. Tumor biopsies from cancerous uterine cervix were collected from 216 women registered at Hospital do Câncer II of Instituto Nacional de Câncer, and infecting HPV was typed. A3B expression levels were quantified from RNA samples extracted from cervical biopsies using real-time quantitative PCR. Median A3B expression levels were higher among HPV18+ samples when compared to HPV16+ counterparts and were also increased compared to samples positive for other HPV types. In squamous cell carcinoma, HPV18+ samples also showed increased median A3B expression when compared to HPV Alpha-9 species or only to HPV16+ samples. Our findings suggest that A3B expression is differentially upregulated in cervical cancer samples infected with HPV18. A3B could be potentially used as a biomarker for HPV infection and as a prognostic tool for clinical outcomes in the context of cervical cancer.

IntroductionThe human papillomavirus (HPV) E5 gene encodes a small and highly hydrophobic oncoprotein that affects immune evasion, cell proliferation, loss of apoptotic capacity and angiogenesis in tumors. E5 shows an affinity for biological membranes and was associated with an increase of epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) signaling through the accumulation of EGFR in cellular membranes. Due to the frequent integration of the HPV genome into the host cell genome, E5 is frequently not transcribed in cervical tumors.AimIn this study we looked forward to verifying whether the potential expression of E5 protein in human papillomavirus 16 positive (HPV16+) and human papillomavirus 18 positive (HPV18+) cervical tumors was associated with levels of EGFR and vascular endothelial growth factor A (VEGFA) transcription and with patients overall survival.ResultsAssociation between the presence of E5 transcripts and viral genome disruption was observed for HPV16+ and HPV18+ tumors. Association was not observed between tumors potentially capable of translating E5 and EGFR or VEGFA transcriptional levels. Similarly, the capability of translating E5 and overall survival in patients with HPV16+ squamous cell carcinoma tumors stage ≥ IB2 were not associated.ConclusionThe likely presence of E5 transcripts was neither associated to a higher activity of the EGFR‐VEGFA pathway nor to the overall survival of patients with HPV16+ squamous cell carcinoma in stages ≥ IB2.