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

Differences in the mutation of the p53 gene in exons 6 and 7 in cervical samples from HIV- and HPV-infected women

Background

Human Papillomavirus (HPV) infection is a serious problem for human immunodeficiency virus (HIV)-infected women, increases their risk of cervical lesions and cancer. In cervical carcinogenesis, mutations in the p53 gene occur most frequently within exons 5–8. To our knowledge, no previous studies have analyzed mutations in exons 5–8 of the p53 gene in HIV- and HPV-infected women. In our study, we verified these mutations in women with and without cervical abnormalities.

Findings

The study included 160 women, divided into three groups: (1) 83 HPV- and HIV-infected women (HIV group); (2) 37 HPV-infected/HIV-uninfected (control group); and (3) 40 normal cytology/DNA-HPV negative/HIV-uninfected women (negative control p53 reactions). HPV-DNA was detected using polymerase chain reaction (PCR) and genotyping by PCR-restriction fragment length polymorphism analysis. Using primers for exons 5–8, the mutation of the p53 gene was verified by PCR-single strand conformational polymorphism. The total mutation of the p53 gene in exons 5–8 was not significantly associated with the HIV and control groups. The mutations in exon 7 were the highest in the HIV group (43.8%) and in exon 6 in the control group (57.2%) (p = 0.0793) suggesting a tendency toward differential mutation in exon 7 in the HIV group.

Conclusions

Our study provides preliminary evidence that the mutation in exon 7 might be an important differentiating factor for cervical carcinogenesis in HIV-infected women. This aspect deserves an additional cross-sectional and longitudinal study using a larger sample size with a higher number of High-grade squamous intraephitelial lesion (HSIL) to observe the evolution of cervical lesions.

A review of methods for detect human Papillomavirus infection

Human Papillomavirus (HPV) is the most common sexually transmitted virus. Worldwide, the most common high-risk (HR)-HPV are -16/18, and approximately 70% of cervical cancers (CC) are due to infection by these genotypes. Persistent infection by HR-HPV is a necessary but not sufficient cause of this cancer, which develops over a long period through precursor lesions, which can be detected by cytological screening. Although this screening has decreased the incidence of CC, HPV-related cervical disease, including premalignant and malignant lesions, continues to be a major burden on health-care systems. Although not completely elucidated, the HPV-driven molecular mechanisms underlying the development of cervical lesions have provided a number of potential biomarkers for both diagnostic and prognostic use in the clinical management of women with HPV-related cervical disease, and these biomarkers can also be used to increase the positive predictive value of current screening methods. In addition, they can provide insights into the biology of HPV-induced cancer and thus lead to the development of nonsurgical therapies. Considering the importance of detecting HPV and related biomarkers, a variety of methods are being developed for these purposes. This review summarizes current knowledge of detection methods for HPV, and related biomarkers that can be used to discriminate lesions with a high risk of progression to CC.

Adeno-associated virus may play a protective role against human papillomavirus-induced cervical lesions independent of HIV serostatus

This study investigated the prevalence of adeno-associated virus (AAV) and human papillomavirus (HPV) DNA in cervical samples of HIV-seropositive and -seronegative women attending a clinic in south-eastern Brazil. Both viruses were investigated by polymerase chain reaction (PCR) and cytological exams were performed. AAV was typed by PCR and restriction fragment length polymorphism analysis. AAV prevalence was 19.7% (56/284), with 18.7% (21/112) and 20.3% (35/172) in HIV-positive and -negative women, respectively. AAV type 2 was the single virus type detected. AAV was detected with higher frequency in HPV-infected women ( P < 0.05) as was HPV in HIV-positive women ( P < 0.05). The AAV–HPV co-infected women showed a lower rate of atypical squamous cells of undetermined significance or cervical intraepithelial neoplasia development compared with those infected only with HPV. The prevalence of AAV2 confirms this type as the most common in human samples. This is the first report examining AAV in cervical samples of HIV-infected women and indicates that HIV infection does not appear to influence AAV prevalence or AAV–HPV co-infection.

Type-specific HPV prevalence in cervical cancer and high-grade lesions in Latin America and the Caribbean: systematic review and meta-analysis

Background

Cervical cancer is a major public health problem in Latin America and the Caribbean (LA&C), showing some of the highest incidence and mortality rates worldwide. Information on HPV type distribution in high-grade cervical lesions (HSIL) and invasive cervical cancer (ICC) is crucial to predict the future impact of HPV16/18 vaccines and screening programmes, and to establish an appropriate post-vaccinal virologic surveillance. The aim was to assess the prevalence of HPV types in HSIL and ICC in studies in LA&C.

Methods and Findings

We performed a systematic review, following the MOOSE guidelines for systematic reviews of observational studies, and the PRISMA statement for reporting systematic reviews and meta-analyses. Inclusion criteria were at least ten cases of HSIL/ICC, and HPV-type elicitation. The search, without language restrictions, was performed in MEDLINE, Cochrane Library, EMBASE, LILACS from inception date to December 2009, proceedings, reference lists and consulting experts. A meta-analysis was performed using arc-sine transformations to stabilize the variance of simple proportions. Seventy-nine studies from 18 countries were identified, including 2446 cases of HSIL and 5540 of ICC. Overall, 46.5% of HSIL cases harbored HPV 16 and 8.9% HPV18; in ICC, 53.2% of cases harbored HPV 16 and13.2% HPV 18. The next five most common types, in decreasing frequency, were HPV 31, 58, 33, 45, and 52.

Study's limitations comprise the cross-sectional design of most included studies and their inherent risk of bias, the lack of representativeness, and variations in the HPV type-specific sensitivity of different PCR protocols.

Conclusions

This study is the broadest summary of HPV type distribution in HSIL and ICC in LA&C to date. These data are essential for local decision makers regarding HPV screening and vaccination policies. Continued HPV surveillance would be useful, to assess the potential for changing type-specific HPV prevalence in the post-vaccination era in Latin America.

Diversity and uncommon HPV types in HIV seropositive and seronegative women attending an STI clinic

Given the causal relationship between specific types of HPV with cervical cancer and precursor lesions, it is important to identify the viral type involved. The aim of this study is to access the prevalence of HPV types in HIV seropositive and seronegative women. Accordingly, 77 HPV positive cervical samples were obtained from 284 women (seropositive (n=112) and seronegative (n=172) for HIV) who attended a Sexually Transmitted Infection clinic, in Vitoria, Southeastern Brazil. Viral DNA was amplified by PCR using MY09/MY11 degenerated primers and the genotyping was performed by Restriction Fragment Length Polymorphism. Seventy five out of the 77 HPV samples were genotyped: 6, 11, 13, 16, 18, 26, 31, 31b, 32, 33, 34, 35, 52, 53, 55, 56, 58, 59, 61, 62, 64, 66, 71, 81, 83, 84. The most prevalent type was HPV16 followed by HPV types 6, 11 and 53. Fifty five percent and 45% belonged to high and low risk types, respectively. High risk types corresponded to 59% and 54.5% of the HPV detected in HIV seronegative and seropositive women, respectively. The uncommon HPV 13 type in cervical samples was also observed in this study. The oncogenic types were more common in the HIV seronegative samples and the number of cases with multiple infections was similar for the two groups. HPV typing is not only important clinically for the establishment of monitoring and treatment of a patient, it also provides knowledge of the viral types circulating in a population, which is of interest in the development of prevention and treatment programs for this disease.

Human papillomavirus in women with and without HIV-1 infection attending an STI clinic in Vitoria, Brazil

We conducted a cross-sectional study in Vitória, Brazil, to assess the prevalence of human papillomavirus (HPV) infection in HIV-positive and HIV-negative women attending a sexually transmitted infection (STI)/AIDS clinic. We also investigated the presence of HPV genotypes and assessed covariates for HIV infection. Enrolled patients received a gynecological evaluation, and cervical scrape samples were collected for cytological analysis and HPV-DNA polymerase chain reaction (PCR). A blood sample was obtained to determine HIV status. HPV infection and squamous intraepithelial lesions were studied in 284 women, 112 (39.4%) HIV-positive women and 172 (60.5%) HIV-negative women. HPV-DNA was detected in 133 (46.8%). HIV-infected women were almost twice as likely to be concurrently infected with HPV than HIV-negative women (OR = 1.87 95% CI: 1.16-3.03). The high proportion of HPV detected among women attending an STI/AIDS clinic, particularly among HIV-infected women, proves the importance of screening this high-risk group in the hope of earlier detection and treatment of cervical intraepithelial neoplasia (CIN).

The use of viral load as a surrogate marker in predicting disease progression for patients with early invasive cervical cancer with integrated human papillomavirus type 16

OBJECTIVE

The purpose of this study was to assess the effectiveness of the use of human papillomavirus type 16 (HPV16) physical status and viral load in combination to predict clinical outcome during cervical development.

STUDY DESIGN

A follow-up study was monitored in association with HPV integration and viral load in 121 cervical samples with the use of multiplex quantitative polymerase chain reaction.

RESULTS

A significant increase of viral load was found earlier from preinvasive to invasive groups compared with normal groups, except with clinical staging and clinical outcome. High occurrence of integrated HPV16 was observed in preinvasive (27/44 samples) and invasive cervical carcinoma (40/68 samples). Cervical progression was observed significantly in most preinvasive (18/27 samples) and invasive cases (25/40 samples) that were infected with integrated HPV. Integrated HPV16 with significant viral load can be used as a predictive marker for tumor progression in the early stage of invasive cervical carcinoma.

CONCLUSION

Integrated HPV16 in combination with viral load is a predictive indicator for tumor progression in early invasive stage but not in preinvasive and advanced invasive stage.

Low prevalence of p53, p16(INK4a) and Ha-ras tumour-specific mutations in low-graded actinic keratosis

BACKGROUND

Ultraviolet radiation induces DNA damage and is the major risk factor for the development of non-melanoma skin cancer (NMSC). Different mutation rates of p53, p16(INK4a) and Ha-ras in cutaneous squamous cell carcinoma (SCC) and the earlier stage actinic keratosis (AK) have been reported.

OBJECTIVES

To assess the presence of missense mutations in hotspot exons of p53, p16(INK4a) and Ha-ras in low-graded AK.

PATIENTS/METHODS

Cryo-biopsies of 75 sun-exposed AK lesions and 75 sun-shielded areas of normal skin from 75 AK patients were analysed to identify mutations in p53 (exons 7 and 8), p16(INK4a) (exon 2) and Ha-ras (exon 1) using polymerase chain reaction (PCR) followed by direct sequencing. As a representative subset of the specimens, ten mutation-negative AK were also micro-dissected in order to exclude the possibility that additional mutations were undetected.

RESULTS

Eight missense and one nonsense point mutations were found in the 75 AK lesions examined (12%), of which seven (9%) were tumour-specific (i.e. present in AK lesions only) and two (3%) were p16(INK4a) mutations (i.e. also detected in normal skin). Three of the tumour-specific mutations (42%) were cytosine (C) to thymine (T) transitions at pyrimidine-rich sequences. Tumour-specific mutations were identified in 1% of p16(INK4a) (exon 2), 1% of Ha-ras (exon 1) and at a higher rate of 7% in p53 (exons 7 and 8), including one nonsense mutation.

CONCLUSIONS

The evaluation of a large number of AK specimens in this study have found a low gene mutation rate in low-graded AK lesions. p53 mutations rather than p16(INK4a) and/or Ha-ras mutations may be an early event in the development of AK to cutaneous SCC.

Viral DNA load, physical status and E2/E6 ratio as markers to grade HPV16 positive women for high-grade cervical lesions

OBJECTIVES

Cervical intraepithelial neoplasias (CIN) associated with high-risk (HR) human papillomavirus infection, in addition to HR-HPV typing need other viral marker testing to distinguish a subset of lesions with clinical relevant infections. This study has evaluated the significance of viral markers, such as viral load, physical status and E2/E6 ratio, to stratify HPV16 infected women at a single point in time for grade of cervical lesions.

METHODS

One hundred sixty-six cytological specimens were selected from women with low (n=72) and high (n=94) grade squamous intraepithelial lesions (SIL), and positive to HPV16. All the 72 LSIL were CINI, 83 of the 94 HSIL were CINII/III and 11 SCC (Squamous Cervical Carcinoma). Cytological specimens were analysed by two different SYBR Green Real-time PCR assays (RT-PCR). Specific primers for both E2 and E6 viral genes and GAPDH cellular gene were designed to determine viral load, physical status and E2/E6 ratio.

RESULTS

The viral load was significantly higher in HSIL than in LSIL. In CINI episomal DNA was prevalent (72.2%), mixed forms (episomal and integrated) were 27.8%, suggestive of an early integration of viral DNA into cellular genome, no pure integrated forms were detected. However in CINII/III mixed DNA forms were prevalent (73.5%). In SCC pure integrated DNA was prevalent (81.8%) in absence of episomal forms. E2/E6 ratio decreased significantly from CINI to CINII/III and SCC with a linear trend. The logistic regression analysis showed that viral load higher than 1.38x10(6) genome copies per 300 ng of total DNA associated with E2/E6 ratio lower than 0.90 was highly significant in differentiating CINII/III versus CINI, while the only E2/E6 value lower than 0.17 was significant in differentiating SCC from CINI.

CONCLUSIONS

Viral load higher than 1.38x10(6) genome copies per 300 ng of total DNA and E2/E6 ratio values allow HPV16 infected women with high grade cervical intraepithelial lesions to be recognized.

Human papillomavirus status and cervical abnormalities in women from public and private health care in Rio de Janeiro State, Brazil

This article reports the HPV status and cervical cytological abnormalities in patients attended at public and private gynecological services from Rio de Janeiro State. It also comments the performance of each HPV DNA tests used. A set of 454 women from private health clinics was tested by routine Capture Hybrid II HPV DNA assay. Among these, 58.4% presented HPV and nearly 90% of them were infected by high risk HPV types. However, this group presented few premalignant cervical lesions and no invasive cervical cancer was registered. We also studied 220 women from low income class attended at public health system. They were HPV tested by polymerase chain reaction using My09/11 primers followed by HPV typing with E6 specific primers. The overall HPV prevalence was 77.3%. They also showed a high percentage of high squamous intraepithelial lesion-HSIL (26.3%), and invasive cervical carcinoma (16.3%). HPV infection was found in 93.1% and 94.4% of them, respectively. The mean ages in both groups were 31.5 and 38 years, respectively. In series 1, HPV prevalence declined with age, data consistent with viral transient infection. In series 2, HPV prevalence did not decline, independent of age interval, supporting not only the idea of viral persistence into this group, but also regional epidemiological variations in the same geographic area. Significant cytological differences were seen between both groups. Normal and benign cases were the most prevalent cytological findings in series 1 while pre-malignant lesions were the most common diagnosis in the series 2. HPV prevalence in normal cases were statistically higher than those from series 1 (p<0.001), indicating a higher exposure to HPV infection. Women from both samples were referred for previous abnormal cytology. However, socio-demographic evidence shows that women from series 1 have access to treatment more easily and faster than women from series 2 before the development of pre-malignant lesions. These data provides baseline support for the role of social inequalities linked to high risk HPV infection leading to cervical cancer. Broadly screening programs and the development of safe and effective vaccines against HPV would diminish the toll of this disease that affect mainly poor women.

The natural history of cervical HPV infection: unresolved issues

The identification of high-risk human papillomavirus (HPV) types as a necessary cause of cervical cancer offers the prospect of effective primary prevention and the possibility of improving the efficiency of cervical screening programmes. However, for these opportunities to be realized, a more complete understanding of the natural history of HPV infection, and its relationship to the development of epithelial abnormalities of the cervix, is required. We discuss areas of uncertainty, and their possible effect on disease prevention strategies.

HPV prevalence, viral load and physical state of HPV-16 in cervical smears of patients with different grades of CIN

Human papillomavirus (HPV) infection is the most important event in malignant transformation of human cervical epithelium. We analysed in cervical smears, HPV genotypes with a focus on single/multiple infections, then characteristics of HPV-16 infections (presence of other genotypes, viral load and physical state) according to the grade of histological lesions. The purpose of this study was to know if these parameters could allow to differentiate histological diagnoses. DNA was extracted from 363 cervical samples corresponding to 24 cases without lesion, 96 CIN1, 92 CIN2, 144 CIN3 and 7 cancers. Our results show that HPV-16 was predominant and its prevalence increased with the severity of lesions (CIN1: 27.1%; CIN3: 65.3%). In addition, we showed that the frequency of single infections, as compared with multiple infections, increased with the severity of the lesion (CIN1: 25.0%; CIN3: 54.8%). Among HPV-16 positive samples (n = 170), we found that viral load, determined on cervical samples by real-time PCR, did not vary significantly according to the different CIN grades. Concerning HPV-16 integration, the mixed and integrated HPV-16 forms, already present in women with normal histology, increased to the benefit of pure episomal forms with the severity of lesions (normal cervix: 28.6%; CIN3: 73.8%). Thus, our data raise the question of the viral load as a valuable clinical parameter to discriminate between lesion grades. Moreover, we emphasize integration as an early event in cervical carcinogenesis, increasing with the severity of lesions. Finally, this study underlines the importance of single versus multiple infections linked to the severity of CIN.

Early integration of high copy HPV16 detectable in women with normal and low grade cervical cytology and histology

BACKGROUND

Integration of human papillomavirus (HPV) DNA has been considered a late event in cervical carcinogenesis. However, integrated forms of HPV were recently detected in cancer precursor lesions using a new real time polymerase chain reaction (PCR) to detect the deletions at the 3362-3443 region of HPV16 E2 OBJECTIVE: To study the frequency of HPV16 DNA integration in cervical lesions and compare the sensitivity of an additional upstream region of the E2 ORF (2962-3138) in detecting HPV integration.

METHODS

Using the TaqMan based PCR, HPV16 positive DNA samples were analysed in 164 cervical scrapings from women participating in a multicentre screening trial. Biopsy confirmation was available in 62 cases.

RESULTS

Primers targeting the 3362-3443 region detected the majority of E2 deletions. In only 23% of the samples was the E2 upstream region equal or better target than the 3362-3443 region. Mixed (episomal/integrated) pattern was the most prevalent physical state of HPV16, also present in PAP smears with normal morphology. Pure integrated form was most prevalent in HSIL and cancer lesions, but also detectable in low grade abnormalities (NSIL, ASC-US, LSIL). Women with only integrated HPV16 were almost 10 years older than those with episomal HPV16. Viral load of integrated HPV16 was related to cytological abnormality (p = 0.003) but not to histology.

CONCLUSIONS

Integrated HPV16 is present in low grade cervical lesions, mostly mixed with the episomal form. Women with the pure integrated form of HPV16 are older than those with the other forms.