Persistent High-risk Human Papillomavirus Infection Research Articles

Genetic and Environmental Factors in Invasive Cervical Cancer: Design and Methods of a Classical Twin Study.

Persistent high-risk human papillomavirus (HPV) infection is a necessary prerequisite for development of cervical cancer and its precursor lesion, high-grade squamous intraepithelial lesion (HSIL). However, HPV infection is not sufficient to drive this process, and genetic and environmental factors may also play a role. The Cervical Cancer, Genetics and Environment Twin Study was established to investigate the environmental and genetic influences on variation in susceptibility to cervical pre-cancer in 25- to 69-year-old monozygotic (MZ) and dizygotic (DZ) twins recruited through the Australian Twin Registry. Reviews of Papanicolaou (Pap) screening histories were undertaken to identify individual women with a history of an abnormal Pap test. This was followed by detection of HPV in archival Pap smears of selected twin pairs to determine HPV persistence. Selected twin pairs also completed a detailed questionnaire on socio-demographic characteristics, sexual behavior, and HPV knowledge. In future analyses, under the assumptions of the classical twin design, case-wise concordance for persistent HPV infection and HSIL will be calculated for MZ and DZ twin pairs, and twin pairs (both MZ and DZ) who are discordant for the above outcomes will be used to assess the contributions of measured environmental risk factors. The study examines factors related to HPV persistence and development of HSIL among female MZ and DZ twins. The results will contribute to our understanding of the natural history of cervical HPV infection and the relative contributions of genetic and environmental factors in disease progression.

Human Papillomavirus Downregulates the Expression of IFITM1 and RIPK3 to Escape from IFNγ- and TNFα-Mediated Antiproliferative Effects and Necroptosis.

The clearance of a high-risk human papillomavirus (hrHPV) infection takes time and requires the local presence of a strong type 1 cytokine T cell response, suggesting that hrHPV has evolved mechanisms to resist this immune attack. Using an unique system for non, newly, and persistent hrHPV infection, we show that hrHPV infection renders keratinocytes (KCs) resistant to the antiproliferative- and necroptosis-inducing effects of IFNγ and TNFα. HrHPV-impaired necroptosis was associated with the upregulation of several methyltransferases, including EZH2, and the downregulation of RIPK3 expression. Restoration of RIPK3 expression using the global histone methyltransferase inhibitor 3-deazaneplanocin increased necroptosis in hrHPV-positive KCs. Simultaneously, hrHPV effectively inhibited IFNγ/TNFα-mediated arrest of cell growth at the S-phase by downregulating IFITM1 already at 48 h after hrHPV infection, followed by an impaired increase in the expression of the antiproliferative gene RARRES1 and a decrease of the proliferative gene PCNA. Knockdown of IFITM1 in uninfected KCs confirmed its role on RARRES1 and its antiproliferative effects. Thus, our study reveals how hrHPV deregulates two pathways involved in cell death and growth regulation to withstand immune-mediated control of hrHPV-infected cells.

High-risk human papillomavirus infection clearance following conization among patients with cervical intraepithelial neoplasm grade 3 aged at least 45years.

To investigate high-risk human papillomavirus (HPV) infection clearance rates following successful cold knife conization and factors predictive of HPV clearance among patients with cervical intraepithelial neoplasm grade 3. The present retrospective study analyzed clinical data from patients aged at least 45years with cervical intraepithelial neoplasm grade 3 who had undergone successful cold knife conization and attended regular follow-up at Peking Union Medical College Hospital, China, between January 1, 2002 and December 31, 2012. HPV clearance rates and potential indicators for HPV clearance were analyzed. Data from 156 patients were included; persistent high-risk HPV infection was recorded in 78 (50.0%), 45 (28.8%), 35 (22.4%), 24 (15.4%), and 21 (13.5%) patients at 4, 8, 12, 18, and 24months after conization, respectively. Clearance rates were significantly lower among patients aged at least 55years compared with younger patients, with increased odds of persistent HPV infection at 8months (odds ratio [OR] 4.038; 95% confidence interval [CI] 1.766-10.839), 12months (OR 5.923; 95% CI 2.450-16.604), 18months (OR 5.957; 95% CI 2.031-17.469), and 24months (OR 5.327; 95% CI 1.909-17.971) compared with patients aged 45-49years. Age was a prognostic factor for post-operative high-risk HPV infection clearance. Lower clearance rates were observed among patients aged at least 55years.

MiR-224-3p inhibits autophagy in cervical cancer cells by targeting FIP200.

Cervical cancer (CC) is a malignant solid tumor, which is one of the main causes of morbidity and mortality in women. Persistent High-risk human papillomavirus (hrHPV) infection is closely related to cervical cancer and autophagy has been suggested to inhibit viral infections. miRNAs have been reported to regulate autophagy in many solid tumors with many studies implicating miR-224-3p in the regulation of autophagy. In this study, we performed a miRNA microarray analysis on CC tissues and found that a large number of miRNAs with differential expressions in hrHPV-infected tissues. We identified miR-224-3p as a candidate miRNA selectively up regulated in HPV-infected tissues and cell lines. Further analysis revealed that miR-224-3p regulates autophagy in cervical cancer tissues and cell lines. While the overexpression of miR-224-3p inhibits autophagy in HPV-infected cells, knocking down endogenous miR-224-3p increases autophagy activity in the same cells. In addition, we found that miR-224-3p directly inhibits the expression of autophagy related gene, FAK family-interacting protein of 200 kDa (FIP200). In summary, we found that miR-224-3p regulates autophagy in hrHPV-induced cervical cancer cells through targeting FIP200 expression.

Human Papillomavirus.

Individuals with inherited immunodeficiencies, autoimmune disorders, organ or bone marrow transplantation, or infection with human immunodeficiency virus (HIV) are at increased risk of infection with both low-risk and high-risk human papillomavirus (HPV) types. Chronic immunosuppression provides an environment for persistent HPV infection which carries a higher risk of malignant transformation. Screening guidelines have been developed or advocated for processes that have detectable premalignant lesions, such as anal cancer or cervical cancer. For other anatomic locations, such as cutaneous, penile, and oropharyngeal, a biopsy of suspicious lesions is necessary for diagnosis. HPV cannot be cultured from clinical specimens in the laboratory, and diagnosis relies on cytologic, histologic, or molecular methods.

Linear viral load increase of a single HPV-type in women with multiple HPV infections predicts progression to cervical cancer.

Persistent high-risk human papillomavirus (HPV) infection is strongly associated with development of high-grade cervical intraepithelial neoplasia or cancer (CIN3+). In single type infections, serial type-specific viral-load measurements predict the natural history of the infection. In infections with multiple HPV-types, the individual type-specific viral-load profile could distinguish progressing HPV-infections from regressing infections. A case-cohort natural history study was established using samples from untreated women with multiple HPV-infections who developed CIN3+ (n = 57) or cleared infections (n = 88). Enriched cell pellet from liquid based cytology samples were subjected to a clinically validated real-time qPCR-assay (18 HPV-types). Using serial type-specific viral-load measurements (≥3) we calculated HPV-specific slopes and coefficient of determination (R(2) ) by linear regression. For each woman slopes and R(2) were used to calculate which HPV-induced processes were ongoing (progression, regression, serial transient, transient). In transient infections with multiple HPV-types, each single HPV-type generated similar increasing (0.27copies/cell/day) and decreasing (-0.27copies/cell/day) viral-load slopes. In CIN3+, at least one of the HPV-types had a clonal progressive course (R(2) ≥ 0.85; 0.0025copies/cell/day). In selected CIN3+ cases (n = 6), immunostaining detecting type-specific HPV 16, 31, 33, 58 and 67 RNA showed an even staining in clonal populations (CIN3+), whereas in transient virion-producing infections the RNA-staining was less in the basal layer compared to the upper layer where cells were ready to desquamate and release newly-formed virions. RNA-hybridization patterns matched the calculated ongoing processes measured by R(2) and slope in serial type-specific viral-load measurements preceding the biopsy. In women with multiple HPV-types, serial type-specific viral-load measurements predict the natural history of the different HPV-types and elucidates HPV-genotype attribution.

Long-Term Risk for Noncervical Anogenital Cancer in Women with Previously Diagnosed High-Grade Cervical Intraepithelial Neoplasia: A Danish Nationwide Cohort Study.

High-risk human papillomavirus (HPV) is essential for developing high-grade cervical intraepithelial neoplasia (CIN2 and CIN3) and has also been associated with noncervical anogenital cancers. However, limited knowledge exists about the long-term risk for anal, vulvar, and vaginal cancer following CIN2 or CIN3 diagnosis. In a nationwide cohort study, we followed nearly 2.8 million women born in 1918-1990 who were recorded as living in Denmark between January 1, 1978 and December 31, 2012. The cohort was linked to multiple nationwide registers to obtain information on cancer diagnoses and confounders. Follow-up started when the women reached 18 years, date of immigration, or January 1978, and continued until emigration, death, December 31, 2012, or the date of first diagnosis of anogenital or rectal cancer. Women with a history of CIN2 or CIN3 had higher risks for subsequent anal, vulvar, and vaginal cancer than women with no such history. The relative risks were higher for CIN3 than CIN2. No excess risk was found for rectal cancer. Analyses in which time since first CIN3 was taken into account showed increased relative risks for anal [HR = 4.8; 95% confidence interval (CI), 3.3-7.0], vulvar (HR = 3.2; 95% CI, 2.0-5.3), and vaginal (HR = 5.5; 95% CI, 2.4-12.3) cancers ≥25 years after CIN3 diagnosis. Women with a history of CIN2 or CIN3 have a long-term increased relative risk for developing anal, vulvar, and vaginal cancer due to an impaired ability to control a persistent HPV infection. This finding adds to our understanding of the relation between HPV infection and noncervical anogenital cancer. Cancer Epidemiol Biomarkers Prev; 25(7); 1090-7. ©2016 AACR.

Genetic and epigenetic mechanisms of regulation of human papillomavirus

Infections with high-risk human papillomaviruses (HPV) are the etiological factor of certain types of human cancers in anogenital tract and head and neck cancers. Extensive epidemiological studies demonstrated the association of persistent high-risk HPV infection and the later development of cervical and other cancers. Experimental data using cell lines models and cervical cancers demonstrate that in more than 99 % of clinical samples the viral E6 and E7 genes are retained and expressed. These genes can transform human cells and inhibition of their expression in cancer cells results in loss of neoplastic growth properties. Molecular mechanisms of immortalization and transformation by E6 and E7 have extensively been investigated. However, the mechanism of E6 and E7 deregulation that triggers the shift from permissive infection to neoplastic transforming infection is still unclear. This review describes the current knowledge about the viral life cycle and discusses the molecular mechanisms that potentially allow the virus to escape its normal control and may trigger neoplastic progression. The molecular clarification of these events required for transformation of HPV-infected cells into cancer will provide a basis for conceptually novel diagnostic and therapeutic strategies and approaches.

Cohort Profile: African Collaborative Center for Microbiome and Genomics Research (ACCME)

Abstract 65 Background: Cervical cancer is the second most common cancer in Africa. Much remains unknown about the prevalence and pathogenicity of human papillomavirus (HPV) types and the mechanism of disease, and there is a need for new biomarkers for screening programs. Methods: ACCME is a multicenter prospective cohort study of host germline, somatic and HPV genomics and epigenomics, and vaginal microenvironment; and their association with cervical cancer in 10,000 HIV negative women in Nigeria. Data on demographic, lifestyle, medical history, serum, germline DNA, HPV genotype, and vaginal pH are collected at baseline and during follow up visits every 6 months. Samples of exfoliated cervical cells are analyzed for high risk HPV with Roche LINEAR ARRAY and vaginal bacterial composition and abundance are characterized by deep sequencing of barcoded 16S rRNA gene fragments (V4) on a Illumina MiSeq platform. Colposcopies and biopsies are conducted on participants with clinical lesions and those with persistent high risk HPV infections. Results: By December 2015, 10,000 participants had been enrolled in the ACCME cohort. The mean (SD) age of the study participants at baseline was 40 (10) years. Most of the participants were married (76%), attended university (44%), and had professional jobs (37%). All the study participants have had vaginal sex, 17% have had oral sex, and only 2% have ever had anal sex. We found 30% of the study participants were HPV positive and 70% were HPV negative. The mean (SD) vaginal pH in the study population was 5.2 (0.5). Further analyses to characterize high-risk HPV types and determine persistence will be conducted at each follow up visit. Also, characterization of cervical cytokines and vaginal microbiome will be conducted after the follow up visits for all participants have been conducted. Conclusions: ACCME is a paradigm for translational research in biomarker discovery that addresses high impact public health challenges affecting women's health in Africa and the rest of the world. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST: No COIs from the authors.

Decreased RARβ expression induces abundant inflammation and cervical precancerous lesions

It is well known that vitamin A and its receptors protect against cancer development and that Retinoid Acid Receptor β (RARβ) is epigenetically silenced during tumoral progression. Cervical Cancer (CC) has been causally linked to high risk human papillomavirus (HR-HPV) infection. However, host factors are important in determining the outcome of persistent HR-HPV infection as most cervical precancerous lesions containing HR-HPVs do not progress to invasive carcinomas. Increasing evidence suggests that low diet in vitamin A and their receptors participate in the development of CC. The aim of this study has been to investigate the effects of abated RARβ expression in the development of cervical premalignant lesions in 4 month-old conditional mice (RARβL−/L−). Results demonstrated the development of spontaneous squamous metaplasia, inflammatory infiltrate, enhanced mitotic activity, loss of cell differentiation, as well as decreased apoptosis and p16INK4a protein levels in RARβL−/L− mice cervix. All these changes are hallmarks of moderate dysplasia. Importantly, our results suggest that the low expression of RARβ, may induce the down regulation of p16INK4a, chronic inflammation and decreased apoptosis and may be involved in vulnerability to HR-HPV and early stage cervical carcinogenesis.

P-B20 Evaluation of the feasibility of incorporating HPV DNA- based cervical cancer screening into routine antenatal care in Nigeria

Introduction: Persistent high-risk HPV infection is a necessary cause of cervical cancer. HPV DNA testing is now the primary WHO recommended approach to cervical cancer screening. Cervical cancer screening uptake remains abysmally low in Nigeria and in other low and middle income countries (LMIC). Antenatal care-based HPV DNA testing is a largely unexplored strategy to increase uptake of cervical cancer screening in LMIC. Up to 70% of women in Africa attend ANC at least once during their pregnancy and many attend at least twice. We evaluated the acceptability of HPV DNA testing as part of routine antenatal care among pregnant women and healthcare workers in Nigeria. Methodology: We conducted focus group discussions (FGD) among pregnant women and Key Informant Interviews among healthcare providers at a hospital facility in Abuja, Nigeria. A total of 24 muslim and christian pregnant women were invited for the focus groups and each group comprised of 6–10 participants. Obstetric/Gynaecologists (O&G) and ANC nurses were interviewed. We used content analysis method for data analysis. Coding sheets were developed to summarize findings. Results: Our study showed fair level of knowledge and awareness of cervical cancer and cervical cancer screening among the pregnant women, however, practice was poor, as none of the women had ever been screened for cervical cancer. Lack of awareness about cervical cancer screening, costs, and fear of screening outcome were commonly cited as barriers to uptake. The nurses interviewed expressed reservations about the willingness of pregnant women to participate in screening but there was a high level of willingness among the pregnant women to be screened during the ANC period. Their religion and parity played no role in determining the acceptance of HPV DNA testing in ANC. The O&G specialists expressed full support for integrating HPV DNA testing into routine ANC services. Conclusions: Our results show the need to explore more innovative public health interventions to reduce cervical cancer burden in LMIC.

Establishment and Application of a Method for High-Risk Human Papillomavirus Genotyping in Cervical Cancer Tissue.

Persistent high-risk HPV infection is a major cause of cervical cancer and E6/E7 genes and the Li gene in the HPV genome are key targets to detect high-risk HPV. This study aims to explore the relationship between cervical lesions and E6/7 by establishing a polymerase chain reaction (PCR) to detect multiplex genes based on HPV EE7 genes. It is hoped that such methods will provide a more reliable method for clinical screening and the prevention of cervical cancer. Based on alignment, specific primers were designed for HPV E6/E7 genes, the sequences of which came from five5 high-risk papillomaviruses that are common in China. This enabled an E6/E7 gene detection method based on multiplex PCR to be established. E6/E7 and Li gene testing were then performed on 65 cervical cancer tissue samples. The gene copy number of HPV E6/E7 genes and the Li gene were detected from different classifications by real-time fluorescence quantitative PCR. Out of the 65 cervical cancer tissue samples, 47 (72.31%) showed positive results in E6/E7 multiplex PCR, 21 (32.31%) showed positive results in the Ll gene PCR, and out of the 219 cervical exfoliate cell samples, 56 (25.57%) showed positive results in E6/E7 multiplex PCR, 21 (13.24%) showed positive results in the L1 gene PCR. There were significant differences (p < 0.05) between these two test results. Fluorescent quantitative PCR showed that the ratio of gene copy number of L1 genes and E6/E7 genes was below 1 (p < 0.05) in cervical cancer tissue, in which both the Li and E6/E7 genes coexist. The established HPV multiplex PCR assay based on the design of E6/E7 gene is a specific and sensitive method for the detection and genotype of five high-risk HPVs.

Functional assessment and structural basis of antibody binding to human papillomavirus capsid.

Persistent high-risk human papillomavirus (HPV) infection is linked to cervical cancer. Two prophylactic virus-like particle (VLP)-based vaccines have been marketed globally for nearly a decade. Here, we review the HPV pseudovirion (PsV)-based assays for the functional assessment of the HPV neutralizing antibodies and the structural basis for these clinically relevant epitopes. The PsV-based neutralization assay was developed to evaluate the efficacy of neutralization antibodies in sera elicited by vaccination or natural infection or to assess the functional characteristics of monoclonal antibodies. Different antibody binding modes were observed when an antibody was complexed with virions, PsVs or VLPs. The neutralizing epitopes are localized on surface loops of the L1 capsid protein, at various locations on the capsomere. Different neutralization antibodies exert their neutralizing function via different mechanisms. Some antibodies neutralize the virions by inducing conformational changes in the viral capsid, which can result in concealing the binding site for a cellular receptor like 1A1D-2 against dengue virus, or inducing premature genome release like E18 against enterovirus 71. Higher-resolution details on the epitope composition of HPV neutralizing antibodies would shed light on the structural basis of the highly efficacious vaccines and aid the design of next generation vaccines. In-depth understanding of epitope composition would ensure the development of function-indicating assays for the comparability exercise to support process improvement or process scale up. Elucidation of the structural elements of the type-specific epitopes would enable rational design of cross-type neutralization via epitope re-engineering or epitope grafting in hybrid VLPs.

Development of a fluorescence-based multiplex genotyping method for simultaneous determination of human papillomavirus infections and viral loads.

BackgroundPersistent high-risk human papillomavirus (HPV) infection is correlated with an increased risk of developing intraepithelial lesion or malignancy (NILM). The aims of the current study is to establish a method named BioPerfectus Multiplex Real Time (BMRT) HPV assay for simultaneous typing and quantifying HPVs, and to evaluate it by comparison with HPV GenoArray test and PCR-sequencing method, as well as histological status.MethodsA total of 817 cervical specimens were evaluated by BMRT method and HPV GenoArray test, using PCR-sequencing method as the reference standard; simultaneously, high-risk HPV-16 and -18 DNA loads were assessed in 443 specimens to investigate the correlation with infection outcomes.ResultsThe overall detection coincidence rate between BMRT assay and HPV GenoArray test is 96.6 % and the Kappa value is 0.760. In addition, the sensitivity and positive predictive value of BMRT is 98.4 % and 95.7 % compared with the results detected by PCR-sequencing method, respectively. HPV-16 viral load has a correlation with CINs or worse lesions. By comparing with infected women presenting NILM /cervicitis, the cutoff value for HPV-16 from patients with CINs was 0.827. With this cutoff value, 74.6 % sensitivity and 72.5 % specificity for prediction of HPV-16 infected patients with CINI and higher CIN were achieved. High significance was obtained when comparing the infected women presenting NILM/cervicitis with women either with CIN and cervical carcinomas (p < 0.001).ConclusionsThe BMRT assay seemed to be a good alternative approach for HR-HPV testing, due to its high level of automation and ability to quantify HPV-16, HPV-18 and other HR-HPVs.

Factors associated with type-specific persistence of high-risk human papillomavirus infection: A population-based study.

Persistent genital infection with high-risk (HR) human papillomavirus (HPV) is a prerequisite for cervical cancer development. The aim of this study was to identify factors associated with type-specific persistence of HR HPV infections. From a population-based cohort of 40,399 women participating in cervical cancer screening established during 2002-2005, we selected all HR HPV-positive women (N = 7,778). During follow-up (2005-2008), we collected cervical samples from these women and tested them for HPV DNA to determine type-specific HR HPV persistence in the interval 1-4.5 years after enrolment. Data on hospitalisations, prescriptions and socioeconomic factors were obtained from nationwide registers. Women with abnormal cytology at baseline or who had undergone conisation during follow-up were excluded. Factors associated with persistence were identified by logistic regression analysis. The overall rate of HR HPV persistence was 31.4%. The risk for persistence was significantly increased among women with a previous episode of genital warts (OR, 1.35; 95% CI, 1.04-1.74), current use of oral contraceptives (OR, 1.35; 95% CI, 1.13-1.63) or use of systemic glucocorticoids (OR, 2.04; 95% CI, 1.16-3.56). The number of pregnancies or births or use of a hormonal intrauterine device, hormonal therapy or nonsteroidal anti-inflammatory drugs was not associated with risk for HR HPV persistence. A history of genital warts and current use of oral contraceptives or systemic glucocorticoids increased the risk, potentially indicating a decreased immune response to HPV infection. These findings suggest that host immune response characteristics are important in HR HPV persistence and consequently in cervical cancer development.

The Role of Chlamydia trachomatis in High-Risk Human Papillomavirus Persistence Among Female Sex Workers in Nairobi, Kenya.

Little is known about risk factors for persistent high-risk human papillomavirus (hrHPV) infection in low-income settings, and prior research has not quantified the relative duration of hrHPV infections stratified by risk factors. We compared the duration of hrHPV infection among female sex workers (FSWs) by exposure to sexually transmitted infections (STIs), using a highly sensitive biomarker assay. From 2009 to 2011, 350 FSWs enrolled in this longitudinal study. Every 3 months, sociodemographic and sexual behavior data were collected via questionnaire, and APTIMA assays were used to detect the rRNA of Chlamydia trachomatis (CT), Neisseria gonorrhea, Trichomonas vaginalis, Mycoplasma genitalium, and messenger RNA of the E6/E7 oncoproteins expressed by hrHPV. Among 173 FSW who were infected with hrHPV during the observation period, accelerated failure time models estimated time ratios (TRs) for duration of hrHPV infection, comparing FSW infected with STIs at baseline to STI-uninfected FSWs. Median follow-up time was 26.2 months (interquartile range, 18.8-27.5 months). The median duration of hrHPV infection among all FSWs was 9.3 months (95% confidence interval [CI], 9.3-11.5). The duration of hrHPV infection among FSW infected with CT at baseline was greater than that among FSWs who were uninfected (adjusted TR, 1.7; 95% CI, 1.2-2.6). Among FSWs who were coinfected with hrHPV and CT at baseline, the adjusted TR was 3.4 (95% CI, 2.5-5.4) compared with FSWs infected with hrHPV only. No other STI was associated with hrHPV duration. Recent or concurrent CT infection was associated with prolonged hrHPV infection among a cohort of Nairobi FSWs. Management of CT could reduce risk for hrHPV persistence.

Serial type-specific human papillomavirus (HPV) load measurement allows differentiation between regressing cervical lesions and serial virion productive transient infections.

Persistent high-risk human papillomavirus (HPV) infection is strongly associated with the development of high-grade cervical intraepithelial neoplasia (CIN) or cancer. Not all persistent infections lead to cancer. Viral load measured at a single time-point is a poor predictor of the natural history of HPV infections. However the profile of viral load evolution over time could distinguish nonprogressive from progressive (carcinogenic) infections. A retrospective natural history study was set up using a Belgian laboratory database including more than 800,000 liquid cytology specimens. All samples were submitted to qPCR identifying E6/E7 genes of 18 HPV types. Viral load changes over time were assessed by the linear regression slope. Database search identified 261 untreated women with persistent type-specific HPV DNA detected (270 infections) in at least three of the last smears for a average period of 3.2 years. Using the coefficient of determination (R²) infections could be subdivided in a latency group (n = 143; R² < 0.85) and a regressing group (n = 127; R² ≥ 0.85). In (≥3) serial viral load measurements, serial transient infections with latency is characterized by a nonlinear limited difference in decrease or increase of type-specific viral load (R² < 0.85 and slopes between 2 measurements 0.0010 and −0.0010 HPV copies/cell per day) over a longer period of time (1553 days), whereas regression of a clonal cell population is characterized by a linear (R² ≥ 0.85) decrease (−0.0033 HPV copies/cell per day) over a shorter period of time (708 days; P < 0.001). Using serial HPV type-specific viral load measurements we could for the first time identify regressing CIN2 and CIN3 lesions. Evolution of the viral load is an objective measurable indicator of the natural history of HPV infections and could be used for future triage in HPV-based cervical screening programs.

Correction: Synergistic Effect of Viral Load and Alcohol Consumption on the Risk of Persistent High-Risk Human Papillomavirus Infection

Purpose This prospective study aimed to examine the combined effect of viral load and alcohol consumption on the risk of persistent high-risk (HR) human papillomavirus (HPV) infection. Methods Among women undergoing health screening between 2002 and 2011 at the National Cancer Center, 284 and 122 women with HR-HPV infection and cytological findings of low-grade squamous intraepithelial or lower-grade lesions were followed up for 1 and 2 years, respectively. Multivariate logistic regression analysis was performed, and the relative excess risk due to interaction (RERI) and synergy index (S) were calculated. Results Among drinkers, the risks of 1-year (odds ratio [OR] 4.09, 95% confidence interval [CI] 2.05–8.18) and 2-year persistence (OR 8.08, CI 2.36–27.6) were significantly higher for high HPV loads than for low HPV loads; this association was not seen for non-drinkers. The risks for 1-year (OR 4.14, CI 1.89–9.05) and 2-year persistence (OR 6.61, CI 2.09–20.9) were significantly higher in subjects with a high HPV load who were also drinkers than in those who were non-drinkers. A high HPV load together with a longer drinking duration or higher alcohol consumption was associated with increased risks of 1-year (OR 3.07, CI 1.40–6.75 or OR 2.05, CI 0.87–4.83) and 2-year persistence (OR 6.40, CI 1.72–23.8 or OR 4.14, CI 1.18–14.6). The synergistic effect of alcohol consumption and HR-HPV load was stronger on the risk of 2-year persistence (RERI = 3.26, S = 2.38) than on the risk of 1-year persistence (RERI = 1.21, S = 1.63). Conclusions The synergistic effect of HR-HPV load and alcohol consumption was associated with the risk of HR-HPV persistence and was stronger for longer-term HR-HPV infection. Limiting alcohol consumption might be an important measure to prevent the development of cervical cancer in women with a high HR-HPV load.

Genotyping of High Risk Human Papillomavirus (HPV) among cervical precancer and cancer patients

Introduction: Human papillomavirus (HPV) is a DNA virus which has tropism for epithelial cells, is the major etiological factor for development of cervical precancerous and cancerous lesions. Nearly 100 diff erent types of HPV have been characterized and thereare a large number of other types. HPV infection is one of the most common causes of sexually transmitted disease in both men and women worldwide. It is associated with a variety of clinical conditions that range from innocuous lesions to cancer. Genital HPV types are divided into high and low-risk types, according to the oncogenic potential. Molecular and epidemiologic studies have solidifi ed the association between high risk HPV types (especially HPV-16 and HPV-18) and cervical squamous cell carcinoma. HPV infection is often transient and self-limiting but infection may persists and progress to high grade lesions and cancer. In addition to persistent high-risk HPV infection, other viral factors such as high viral loads, HPV variants, infections with multiple high-risk HPV types and genetic predisposition contribute to the development of cervical cancer. Th e aim of the present study was to detect HPV DNA and identify high risk HPV genotype among women having cervical intraepithelial neoplasia and carcinoma and to evaluate potential effi cacy of prophylactic HPV vaccine. Methods: Cervical swab from histopathologically diagnosed CIN (n=51) and carcinoma (n=39) patients were taken and high risk HPV DNA was detected by HC II assay. Polymerase Chain Reaction was used to identify high risk HPV genotype. Result: HPV DNA was detected in 41 (45.56%) patients by HC II assay. HPV type 16 was detected in 27 (81.82%) followed by type 18 in 3 (9.09%) and type 45 in 2 (6.06%) cases of cervical carcinoma. Among precancerous cases, only type 16 was detected. Conclusion: Knowledge based on HPV prevalence and genotype could be used to predict the effi cacy of cost eff ective prophylactic vaccine, introduction of newer generation vaccine and management of cervical carcinoma.

The clearance of oral high-risk human papillomavirus infection is impaired by long-term persistence of cervical human papillomavirus infection

Persistence of high-risk (HR-) human papillomavirus (HPV) infection of the uterine cervix increases the risk of cervical cancer. Oral HPV infections are among potential covariates of long-term genotype-specific persistent cervical HR-HPV infections. It is not known whether this persistence reflects inability of the host to reject HPV infections in general. A case–control setting was designed to estimate the covariates of long-term persistent cervical HR-HPV infections using multivariate generalized estimating equation (GEE) models. HPV was detected with PCR using GP05+/GP06+-primers and genotyped for 24 HPVs with a Multimetrix-kit. The cases (n = 43) included women who had genotype-specific persistent cervical HR-HPV infection for at least 24 months (24M+) and controls were women who tested repeatedly HPV-negative in their cervical samples (n = 52). These women represent a sub-cohort of the Finnish Family HPV Study. The cases differed significantly from the HPV-negative controls in several aspects: they were younger, had a longer mean time to incident oral HPV infection (40.7 versus 23.6 months), longer duration of oral HPV persistence (38.4 versus 14.1 months), and longer time to clearance of their oral HPV infection (50.0 versus 28.2 months). In multivariate GEE analysis, the second pregnancy during the follow up was the only independent predictor with significant protective effect against 24M+ persistent cervical HR-HPV infections, OR of 0.15 (95% CI 0.07–0.34). To conclude, long-term persistent cervical HR-HPV infections are associated with a prolonged clearance of oral HR-HPV infections while new pregnancy protects against persistent cervical HR-HPV infections.