Human Papillomavirus 16 Lineage D is Associated with High Risk of Cervical Cancer in the Brazilian Northeast Region / Papillomavirus humano 16 da linhagem D associado a alto risco de câncer de colo do útero em região do nordeste brasileiro

Abstract Objective Similar to Human Papillomavirus (HPV) genotypes, different lineages of a genotype also have different carcinogenic capabilities. Studies have shown that specific genotype lineages of oncogenic HPV are associated with variable risks for the development of cervical intraepithelial neoplasia (CIN2/CIN3) and cervical cancer. The present study aimed to analyze the genetic diversity of the HPV16 genotype in women with CIN2/CIN3 and cervical cancer, from the northeast region of Brazil. Methods A cross-sectional multicenter study was conducted in the northeast region of Brazil, from 2014 to 2016. This study included 196 cases of HPV16 variants (59 and 137 cases of CIN2/CIN3 and cervical cancer, respectively). The difference of proportion test was used to compare patients with CIN2/CIN3 and cervical cancer, based on the prevalent HPV16 lineage (p < 0.05). Results According to the histopathological diagnosis, the percentage of lineage frequencies revealed a marginal difference in the prevalence of lineage A in CIN2/CIN3, compared with that in cervical cancer (p = 0.053). For lineage D, the proportion was higher in cancer cases (32.8%), than in CIN2/CIN3 cases (16.9%), with p = 0.023. Conclusion HPV16 lineage A was the most frequent lineage in both CIN2/CIN3 and cervical cancer samples, while lineage D was predominant in cervical cancer, suggesting a possible association between HPV16 lineage D and cervical cancer.

Resumo Objetivo Tanto os tipos quanto as linhagens do Papilomavírus Humano (HPV) parecem ter diferentes capacidades carcinogênicas e estão associados a riscos variados para o desenvolvimento de neoplasia intraepitelial cervical (NIC) e câncer de colo do útero. O presente estudo tem como objetivo analisar a diversidade genética do genótipo HPV 16 nos casos de NIC2/NIC3 e câncer de colo de útero em mulheres da região Nordeste do Brasil. Métodos Estudo transversal de base hospitalar realizado na região Nordeste do Brasil no período de 2014 a 2016. A amostra foi composta por 196 casos da variante HPV-16 (59 casos de NIC2/NIC3 e 137 de câncer do colo do útero). O teste de diferença de proporção foi usado para comparar os grupos NIC2/NIC3 e câncer de colo do útero por linhagem viral em relação à prevalência da linhagem HPV-16. Foi considerada significância estatística o valor de p < 0,05. Resultados As frequências de linhagem por diagnóstico histopatológico mostraram diferença limítrofe da linhagem A no grupo NIC2/NIC3 em relação ao grupo câncer de colo de útero (p = 0,053). Por outro lado, em relação à linhagem D, houve uma proporção maior nos casos de câncer (32,8%) quando comparado ao grupo NIC2/NIC3 (16,9%) e esta diferença se mostrou estatisticamente significante (p = 0,023). Conclusão A linhagem A do HPV-16 foi a mais frequente tanto nas amostras CIN2/CIN3 quanto nas amostras de câncer de colo de útero, enquanto a linhagem D predominou no câncer de colo do útero, sugerindo uma possível associação da linhagem D de HPV-16 com câncer de colo de útero.

Methylation of p16 ink4a promoter is independent of human papillomavirus DNA physical state: a comparison between cervical pre-neoplastic and neoplastic samples

BACKGROUND Epigenetic modifications in host cells, like p16 ink4a methylation, have been considered as putative complementary mechanisms for cancer development. Because only a small proportion of infected women develop cervical cancer, other factors might be involved in carcinogenesis, either independently or in association with high-risk human papillomavirus (HR-HPV) infections, including epigenetic factors. OBJECTIVES We hypothesised that p16 ink4a methylation might have a role in cancer development driven by HPV16, mainly in the presence of intact E1/E2 genes. Thus, our objectives were to assess the status of p16 ink4a methylation and the HPV16 E1/E2 integrity in samples in different stages of cervical diseases. METHODS Presence of HPV16 was determined by E6 type-specific polymerase chain reaction (PCR). Methylation status of the p16 ink4a promoter was assessed by methylation-specific PCR in 87 cervical specimens comprising 29 low-grade (LSIL), 41 high-grade (HSIL) lesions, and 17 cervical cancers (CC). Characterisation of E1 and E2 disruption (as an indirect indicator of the presence of episomal viral DNA) was performed by PCR amplifications. FINDINGS We observed a significantly increased trend (nptrend = 0.0320) in the proportion of methylated p16 ink4a in cervical samples during cancer development. Concomitant E1 and E2 disruptions were the most frequent pattern found in all groups: CC (76%), HSIL (54%), and LSIL (73%). No statistically significant differences between p16 ink4a methylation and E1/E2 integrity, in histological groups, was observed. MAIN CONCLUSIONS There was an increase in methylation of the p16 ink4a promoter from pre-neoplastic lesions to cancer. Additionally, a high frequency of E1/E2 disruptions in LSIL/HSIL suggested that viral DNA integration was an early event in cervical disease. Moreover, the methylation status was apparently independent of HPV16 integrity.