HPV 16 detection in cervical lesions, physical state of viral DNA and changes in p53 gene

Abstract

CONTEXT: Persistent infection with high risk human papillomavirus (HPV) has been linked to cervical carcinoma. Integration of viral DNA into host cell DNA is essential for this cancer development, promoting disruption of the HPV E2 gene, thus leading to unregulated increases in E6 and E7 proteins and inactivating the products of p53 and Rb tumor suppressor genes. OBJECTIVE: To investigate HPV 16 infection in cervical lesions, physical state of viral DNA and p53 gene alterations in a group of women attending a public health service. DESIGN: Prospective, non-controlled, transversal study. SETTING: Gynecological clinic of the School od Medicine, Universidade Federal Fluminense. SAMPLE: 43 consective patients with cervical lesions referred to our service. MAIN MEASUREMENTS: Cases were classified via cytology/histology as normal, HPV infection, condyloma, low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL) and carcinoma. HPV infection was studied via polymerase chain reaction (PCR) using two PCR primer sets, to determine DNA integration. p53 gene changes were investigated by single-strand conformation polymorphism (SSCP) analysis. RESULTS: One normal case, 7 HPV infections, 6 condylomas, 7 LSIL, 14 HSIL and 8 cancers were found, with 95% positive for HPV genome when tested using both L1 and E6 primers. HPV 16 was most prevalent (73.1%). HPV 16 DNA was integrated within the host genome in 3 LSIL. One LSIL progressed to HSIL by 13 months after first diagnosis. Among HPV 16-positive HSIL cases, 50% contained integrated viral DNA. HPV 16 E2 gene disruption was seen in 7 cancers (87.5%). Only smal-cell carcinoma showed intact HPV 16 E2 gene. Abnormal p53 bands detected by PCR/SSCP were observed in 4 cases: 2 squamous carcinoma with parametrium (exon 8) and two cervical intraepithelial neoplasia (CIN) III (exons 5 and 7). All cases presented HPV 16 E2 gene loss. CONCLUSIONS: The sample had a high rate of high-risk HPV detected in benign and malignant lesions; high cervical cancer burden; HPV 16 DNA integration in all except one case of cancer; p53 gene changes in CIN III and in invasive cancer cases associated with DNA integration.

Human papillomavirus infection in Rio de Janeiro, Brazil: a retrospective study

“…Various epidemiological investigations have already shown that periodic convocation of women is essential to conduct a proper follow up, and this helps explain the program's efficiency [24]. We focused on an intermediate-economic-level female population that had good access to health care; in fact, we did not find cancer cases, corroborating the idea that the victims of cervical cancer are poor women, with a low level of education and limited access to medical care [7].…”

“…High annual cancer incidences have been reported in Brazil. Nevertheless, there have been few published epidemiological studies concerning the prevalence of HPV DNA in the female genital tract and the natural history of the infection [7]. Vaccine trials against HPV are underway, and one of the problems in vaccine development is to accurately determine which types of HPV to include, since geographical variations in the prevalence of high-risk types have been observed [8].…”

Human Papillomavirus in Women With and Without HIV-1 Infection Attending an STI Clinic in Vitoria, Brazil

“…HPV-DNA was investigated by PCR, using the protocol previously established which detects a fragment of 450 base pair (bp) of L1 gene region using consensus primers MY09/11. All positive samples were screened for HPV genotype 16 using a PCR reaction to detect the most common types: 6, 11, 16, 18, 31, 33, and 35. A blood sample was collected for HIV testing: enzyme-linked immunosorbent serologic assay (ELISA; HIV-1 Micro-elisa, Organon Laboratories, Boxtel, Holland) and confirmed by indirect immunofluorescent assay (Fiocruz, Rio de Janeiro).…”

Ocorrência de papilomavírus humano na cérvice uterina de mulheres da região ocidental da Amazônia Brasileira

“…De acordo com Bosch et al (2002), em estudo de caso controle com amostras provenientes da cérvice uterina é observado a presença de HPV na faixa e 90% a 100%, com o auxílio de técnicas moleculares. No Brasil, estudos similares observaram a presença do HPV entre 73,9% a 95% das amostras (Noronha et al 1999;Cavalcanti et al 2000;Oliveira et al 2003). As variações encontradas nos trabalhos citados e a porcentagem de HPV observada no presente estudo, deve-se a dois fatores: os trabalhos citados correlacionam os resultados do uso de diferentes técnicas moleculares na metodologia como, por exemplo, PCR, RFLP, hibridização in situ e ou captura híbrida I e II.…”