Padrão de metilação do gene P16INK4A e de infecções por HPV de alto risco acompanham a evolução de lesões cervicais

SUMMARY High-risk human papillomavirus (hr-HPV) infection is necessary but not sufficient for cervical cancer development. Recently, P16INK4A gene silencing through hypermethylation has been proposed as an important cofactor in cervical carcinogenesis due to its tumor suppressor function. We aimed to investigate P16INK4A methylation status in normal and neoplastic epithelia and evaluate an association with HPV infection and genotype. This cross-sectional study was performed with 141 cervical samples from patients attending Hospital Moncorvo Filho, Rio de Janeiro. HPV detection and genotyping were performed through PCR and P16INK4A methylation by nested-methylation specific PCR (MSP). HPV frequency was 62.4% (88/141). The most common HPV were HPV16 (37%), HPV18 (16.3%) and HPV33/45(15.2%). An upward trend was observed concerning P16INK4A methylation and lesion degree: normal epithelia (10.7%), low grade lesions (22.9%), high grade (57.1%) and carcinoma (93.1%) (p < 0.0001). A multivariate analysis was performed to evaluate an association between methylation, age, tobacco exposure, HPV infection and genotyping. A correlation was found concerning methylation with HPV infection (p < 0.0001), hr-HPV (p = 0.01), HSIL (p < 0.0007) and malignant lesions (p < 0.0001). Since viral infection and epigenetic alterations are related to cervical carcinoma, we suggest that P16INK4A methylation profile maybe thoroughly investigated as a biomarker to identify patients at risk of cancer.RESUMO É reconhecido que infecções por papilomavírus humanos de alto risco (HPV) são causa necessária, mas não suficiente para o desenvolvimento do câncer cervical. Recentemente, estudos de silenciamento gênico apontaram que a hipermetilação do gene p16INK4A é importante co-fator para a carcinogênese cervical, eliminando a função supressora de tumor da proteína p16 em lesões malignas. Entretanto poucos estudos avaliaram a relação da metilação com a progressão da doença. Nosso objetivo foi investigar o padrão de metilação do gene P16INK4A em diferentes graus de lesão cervical e sua associação com a infecção por diferentes tipos de HPV. Nosso estudo de corte transversal avaliou 141 amostras cervicais de pacientes atendidas no Hospital Moncorvo Filho, Rio de Janeiro. A detecção e tipagem do HPV foi realizada pela técnica de reação em cadeia da polimerase (PCR), e a metilação do gene P16INK4A pela PCR-metilação específica em formato nested (MSP). A frequência de HPV foi de 62,4% (88/141). O tipo mais prevalente foi o HPV16 (37%), seguido pelo HPV18 (16,3%) e HPV33/45 (15,2%). Curva ascendente foi observada quanto ao padrão de metilação do gene P16INK4A e o grau da lesão: a metilação foi identificada em somente 10,7% das amostras de epitélio normal, em 22,9% das lesões de baixo grau, em 57,1% das lesões de alto grau e em 93,1% dos carcinomas (p < 0,0001). Foram feitas análises univariada e multivariada a fim de correlacionar metilação, idade, exposição ao tabaco, infecção e genótipo de HPV. Foi encontrada correlação da metilação com a infecção pelo HPV (p < 0,0001), genótipos de alto risco (p = 0,01), lesões de alto grau (p < 0,0007) e câncer (p < 0,0001). Uma vez que infecções pelo HPV e alterações epigenéticas mostraram forte associação estatística com o carcinoma cervical, sugerimos que estes padrões de metilação possam ser avaliados como potenciais biomarcadores, combinados à detecção dos HPV oncogênicos para identificação de pacientes em risco de câncer

Prevalence of human papillomavirus infection in the genital tract determined by hybrid capture assay

Human Papillomavirus (HPV) infection is the most prevalent sexually-transmitted virus worldwide. It is known to be the etiological agent of cervical cancer and cervical intraepithelial neoplasia (CIN). Consequently, there is strong motivation to evaluate HPV testing in cervical cancer screening. Recently developed, the second generation of the hybrid capture test (HCA II) is a non-radioactive, relatively rapid, hybridization assay, designed to detect 18 HPV types divided into high and low-risk groups. We evaluated 7,314 patients (5,833 women and 1,481 men) for HPV infection by HCA II. Among them, 3,008 (41.1%) presented HPV infection: 430 (14.2%) had HPV DNA of low risk for cancer, 1,631 (54.2%) had high risk HPV types and 947 (31.5%) had both types. The prevalence in females was 44.9%. The prevalence of HPV DNA in the group for which cytological results were available was slightly higher: 55.3% (1007/1824). Significant differences were detected in the frequency of HPV infection of the cervix between normal cases and those with high-grade squamous-intraepithelial lesions (HSIL)(P<0.0001). Among males, the prevalence was 26.2%, composed of 9.1% in Group A, 9.7% in Group B and 7.4% with multiple infections. We observed that male prevalence was lower and that low-risk types were more frequent than in females. HPV viral load was significantly greater in SILs than in normal or inflammatory cases (P<0.0001), suggesting an association between high viral load values and risk of SIL. Because of high costs, the HCA II test cannot be recommended for routine mass screening for cervical infection in poor countries. Nevertheless, it was found to be a useful tool, when combined with cytology, discovering high-risk infections in apparently normal tissues and revealing silent infections that may be responsible for the maintenance of HPV in the general population. These findings point to the need for close and careful management of patients, thereby reducing overtreatment, allowing analysis of both sexual partners and finally contributing to the control of genital infections associated with a risk for cancer

Analysis of molecular biology techniques for the diagnosis of human papillomavirus infection and cervical cancer prevention

The objective of the present study was to evaluate the usefulness of molecular methodologies to access human papillomavirus genome in the genital tract. Samples from 136 women aged 17 to 52 years old obtained from the Dr. Sérgio Franco Laboratories between 2000 and 2001, were analyzed by the hybrid capture assay and amplified by PCR with generic primers MY09/MY11 and specific primers for types 16, 18, 31, 33, 35, 58. Viral genome was detected in 71.3% of the samples by hybrid capture and 75% by amplification. When cytopathology was used as a reference method for screening lesions, hybrid capture (p=0) and amplification (p=0.002) presented positive association. The 3 methods showed absolute agreement when cytopathology confirmed papillomavirus infection and high grade intraepithelial lesion. Disagreements occurred for 10 cases: seven inflammatory cases positive by PCR and negative for hybrid capture and 3 low squamous intraepithelial lesions positive for hybrid capture but negative for amplification. In conclusion, hybrid capture was shown to be sensitive and specific enough for use in clinical routines. Moreover, the evaluation of viral load values obtained by this method were shown to be related to the severity of the lesion and merit further studies to analyze the possible association with risk of progression to malignancy

Alexander Disease Modeling in Zebrafish: An In Vivo System Suitable to Perform Drug Screening

Alexander disease (AxD) is a rare astrogliopathy caused by heterozygous mutations, either inherited or arising de novo, on the glial fibrillary acid protein (GFAP) gene (17q21). Mutations in the GFAP gene make the protein prone to forming aggregates which, together with heat-shock protein 27 (HSP27), \u3b1B-crystallin, ubiquitin, and proteasome, contribute to form Rosenthal fibers causing a toxic effect on the cell. Unfortunately, no pharmacological treatment is available yet, except for symptom reduction therapies, and patients undergo a progressive worsening of the disease. The aim of this study was the production of a zebrafish model for AxD, to have a system suitable for drug screening more complex than cell cultures. To this aim, embryos expressing the human GFAP gene carrying the most severe p.R239C under the control of the zebrafish gfap gene promoter underwent functional validation to assess several features already observed in in vitro and other in vivo models of AxD, such as the localization of mutant GFAP inclusions, the ultrastructural analysis of cells expressing mutant GFAP, the effects of treatments with ceftriaxone, and the heat shock response. Our results confirm that zebrafish is a suitable model both to study the molecular pathogenesis of GFAP mutations and to perform pharmacological screenings, likely useful for the search of therapies for AxD

Human papillomavirus prevalence, genomic diversity and related risk factors in HIV-positive women from a countryside city in the state of Rio de Janeiro

Human papillomavirus (HPV) can cause genital warts and HPV-related cancer.People living with human immunodeficiency virus (HIV)are more symptomatic for HPV infections.Campos dos Goytacazes,a municipality of Rio de Janeiro,introduced the quadrivalent HPV vaccine (4vHPV)for HIV-positive women four years before initiation of a public vaccination program.This study analyzed the prevalence of HPV infection in HIV-positive women and the variables associated with infectionTwo groups were evaluated:group 1,with Pap smear and HPV-negative polymerase chain reaction (PCR);group 2, individuals with at least one positive result for HPV in PCR or pap smear.PCR was performed in endocervical samples using generic primers, and the LCD-Array Kit was used for genotyping.Univariate and multivariate analyzes were performed.Results in 109 women (Group 1 n = 70; group 2 n = 39)showed an overall HPV prevalence of 36%.Results also showed that 88% (n = 23) and 96% (n = 25)of typed viruses (total of typed viruses n = 26)were included in 4vHPV and 9vHPV (nonavalent HPV),respectively.In univariate analysis,age less than 45 years, a high number of sexual partners,and HIV-viral load were risk factors for infection.However, a CD4 indicator was associated with protection.Although HIV infection is generally related to multiple and rare types of HPV,this study showed that a vast majority of the HPV types found are included in 4vHPV.Considering that age less than 45 years is a risk factor, the use of 4vHPV in Brazil should be extended in the public vaccination program to HIV seropositive women up to age 45 year