Association of HIV status with infection by multiple HPV types

Comparison of the ScreenFire and Xpert HPV assays for the detection of human papillomavirus and cervical precancer among women living with HIV in Malawi

BACKGROUND

The World Health Organization recommends human papillomavirus (HPV) testing for primary cervical cancer screening, including among women living with HIV (WLWH). Low-and-middle-income countries account for 85% of the cervical cancer burden globally, yet have limited access to HPV-based screening, largely due to cost. This study aims to compare the performance of a rapid, isothermal amplification HPV assay (ScreenFire) to that of the Xpert HPV assay for the detection of HPV and cervical precancer among WLWH in Malawi.

METHODS

We utilized stored self- and provider-collected specimens from a prospective cohort study of WLWH in Malawi from July 2020 to February 2022. Specimens were tested with both Xpert and ScreenFire HPV assays. The overall and within-channel non-hierarchical agreement between ScreenFire and Xpert was determined for both self- and provider-collected specimens. Hierarchical ScreenFire HPV positivity by channel was compared to Xpert for each histological diagnosis-cervical intraepithelial neoplasia grade 2 or worse (CIN2+) compared to

RESULTS

315 matched self- and provider-collected specimens had valid results from both Xpert and ScreenFire testing and were included in analyses, of which 279 and 36 were HPV positive and HPV negative, respectively, on Xpert self-collection. Of the 315, 245 (78%) had normal pathology, 21 CIN1 (7%), 14 CIN2 (4%), and 35 CIN3 (11%). Of the 245 with normal pathology, 213 (87%) and 188 (77%) were HPV-positive on Xpert and ScreenFire self-collected specimens, respectively. Among provider-collected specimens, the assays had 80% agreement on overall HPV positivity (unweighted kappa 0.59, 95% 0.50-0.69). ScreenFire was HPV-positive in 90% of self-collected specimens that were HPV-positive on Xpert. Channel agreement between the assays was high for both self- and provider-collected specimens, but slightly lower for HPV18/45. In hierarchical analysis, ScreenFire demonstrated high concordance with Xpert testing for detecting CIN2+ cases in all channels, missing no HPV 16 or HPV 18/45 positive CIN2+ case that was positive on Xpert, in both self- and provider-collected specimens.

CONCLUSION

In this study of stored specimens, the ScreenFire HPV assay performed well in the detection of HPV and CIN2+ among WLWH compared to the Xpert HPV assay. If supported by larger validation studies, ScreenFire could be an affordable alternative point-of-care HPV assay for use in LMICs.

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Grants

• K12HD103085 Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health
• Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health

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Affiliation(s)

Chemtai Mungo Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA.
Anagha Guliam Barnard College of Columbia University, New York City, NY, USA
Lameck Chinula Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA University of North Carolina Project-Malawi, Lilongwe, Malawi
Federica Inturrisi Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
Lizzie Msowoya University of North Carolina Project-Malawi, Lilongwe, Malawi
Tawonga Mkochi University of North Carolina Project-Malawi, Lilongwe, Malawi
Siniya Jawadu University of North Carolina Project-Malawi, Lilongwe, Malawi
Silvia de Sanjosé Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA ISGlobal, Barcelona, Spain
Mark Schiffman Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
Jennifer H Tang Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA University of North Carolina Project-Malawi, Lilongwe, Malawi
Jennifer S Smith Gillings School of Global Public Health, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA

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Comparison of the ScreenFire and Xpert HPV assays for the detection of human papillomavirus and cervical precancer among women living with HIV in Malawi

Background

The World Health Organization (WHO) recommends human papillomavirus (HPV) testing for primary cervical cancer screening, including among women living with HIV (WLWH). Low-and-middle-income countries (LMICs) account for 85% of the cervical cancer burden globally, yet have limited access to HPV-based screening, largely due to cost. This study aims to compare the performance of a rapid, isothermal amplification HPV assay (ScreenFire) to that of the Xpert HPV assay for the detection of HPV and cervical precancer among WLWH in Malawi.

Methods

We utilized stored self- and provider-collected specimens from a prospective cohort study of WLWH in Malawi from July 2020 to February 2022. Specimens were tested with both Xpert and ScreenFire HPV assays. The overall and within-channel non-hierarchical agreement between ScreenFire and Xpert was determined for both self- and provider-collected specimens. Hierarchical ScreenFire HPV positivity by channel was compared to Xpert for each histological diagnosis - cervical intraepithelial neoplasia grade 2 or worse (CIN2+) compared to

Results

315 matched self- and provider-collected specimens had valid results from both Xpert and ScreenFire testing and were included in analyses. Of these, 245 (78%) had normal pathology, 21 CIN1 (7%), 14 CIN2 (4%), and 35 CIN3 (11%). Among provider-collected specimens, the assays had 80% agreement on overall HPV positivity (unweighted kappa 0.59, 95% 0.50-0.69). ScreenFire was HPV-positive in 90% of self-collected specimens that were HPV-positive on Xpert. Channel agreement between the assays was high for both self- and provider-collected specimens, but slightly lower for HPV18/45. In hierarchical analysis, ScreenFire demonstrated high concordance with Xpert testing for detecting CIN2+ cases in all channels, missing no HPV 16 or HPV 18/45 positive CIN2+ case that was positive on Xpert, in both self- and provider-collected specimens.

Conclusion

In this study of stored specimens, the ScreenFire HPV assay performed well in the detection of HPV and CIN2+ among WLWH compared to the Xpert HPV assay. If supported by larger validation studies, ScreenFire could be an affordable alternative point-of-care HPV assay for use in LMICs.

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Key Words Collapse

MESH Headings Collapse

Grants

• K12 HD103085 NICHD NIH HHS

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Affiliation(s)

Chemtai Mungo Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill
Anagha Guliam Barnard College of Columbia University
Lameck Chinula Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill University of North Carolina Project-Malawi, Lilongwe, Malawi
Federica Inturrisi Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
Lizzie Msowoya University of North Carolina Project-Malawi, Lilongwe, Malawi
Tawonga Mkochi University of North Carolina Project-Malawi, Lilongwe, Malawi
Siniya Jawadu University of North Carolina Project-Malawi, Lilongwe, Malawi
Silvia de Sanjosé Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA Gillings School of Global Public Health, University of North Carolina-Chapel Hill
Mark Schiffman Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
Jennifer H. Tang Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill University of North Carolina Project-Malawi, Lilongwe, Malawi
Jennifer S. Smith Gillings School of Global Public Health, University of North Carolina-Chapel Hill

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HPV co-infections with other pathogens in cancer development: A comprehensive review

High-risk human papillomaviruses (HR-HPVs) cause various malignancies in the anogenital and oropharyngeal regions. About 70% of cervical and oropharyngeal cancers are caused by HPV types 16 and 18. Notably, some viruses including herpes simplex virus, Epstein-Barr virus, and human immunodeficiency virus along with various bacteria often interact with HPV, potentially impacting its replication, persistence, and cancer progression. Thus, HPV infection can be significantly influenced by co-infecting agents that influence infection dynamics and disease progression. Bacterial co-infections (e.g., Chlamydia trachomatis) along with bacterial vaginosis-related species also interact with HPV in genital tract leading to viral persistence and disease outcomes. Co-infections involving HPV and diverse infectious agents have significant implications for disease transmission and clinical progression. This review explores multiple facets of HPV infection encompassing the co-infection dynamics with other pathogens, interaction with the human microbiome, and its role in disease development.

Human Papillomavirus Genotype Richness and the Biodiversity of Squamous and Glandular Cervical Dysplasias: A Cross-Sectional Study

The impact of multiple infections on the risk of cervical lesions is a subject of ongoing debate. This study aims to explore whether the richness of HPV genotype infections and the biodiversity of squamous and glandular cervical dysplasias could influence the progression of precancerous lesions. We conducted a cross-sectional analysis involving 469 women who attended the Colposcopy Unit at the European Institute of Oncology in Milan, Italy, from December 2006 to December 2014. HPV type richness was measured as the number of different genotypes per patient. We calculated the associations between richness and age, as well as histologic grade, along with Simpson's biodiversity index for cervical dysplasias. We observed significant inverse relationships between the richness of high-risk (HR) genotypes and both age (p = 0.007) and histologic grade (p < 0.001). Furthermore, as the histologic grade increased, the mean biodiversity index of cervical dysplasias decreased, with exceptions noted in cases of normal histology and adenocarcinoma in situ. Different histologic grades formed five clusters with distinct mean ages and mean biodiversity indices. These findings suggest that HPV genotype richness and the biodiversity of cervical dysplasias may play a crucial role in predicting the risk of high-grade cervical lesions, enabling personalized management of precancers.

Clinical and epidemiological features of high-risk human papillomavirus infection in patients with cervical intraepithelial lesions

OBJECTIVE

In this study, we analyzed the clinical and epidemiological features of high-risk human papillomavirus (HR-HPV) infection in patients with cervical intraepithelial lesions.

METHODS

Retrospective analysis was performed on the clinical data of 240 cases of histologically confirmed cervical squamous intraepithelial lesions to determine any correlation between HPV infection characteristics, age distribution, and cervical epithelial lesions.

RESULTS

Patients between the ages of 31 and 40 with cervical intraepithelial lesions were more likely to have high-grade squamous intraepithelial lesions (HSIL; 40.7%) than low-grade squamous intraepithelial lesions (LSIL; 31.3%) (P < 0.05). In patients with HSIL, HR-HPV16, HR-HPV33, and HR-HPV52 were the most common types of HPV infection, while in patients with LSIL, HR-HPV16, HR-HPV52, and HR-HPV58 were the most common types of HPV infection. The highest percentage of single infections occurred in the HSIL group (69.6%), followed by the LSIL group (68.8%). HSIL was present in a significant number of patients (28.6%) aged 30 years and above who tested positive for 12 HPV types but negative for TCT.

CONCLUSION

The prevalence of HSIL is greatest in younger patients. Patients with cervical epithelial lesions typically have a single infection of a high-risk HPV genotype-HR-HPV16, HR-HPV33, HR-HPV52, or HR-HPV58. Patients aged 30 years and above who test positive for one of 12 types of HPV but negative for TCT are at increased risk for developing HSIL. In order to detect cervical lesions early and begin treatment without delay, colposcopy should be performed regardless of whether or not a high-risk HPV infection is present.

The Potential Risk Compensation after Receiving HPV Vaccination among Men Who Have Sex with Men in Southwest China: A HAPA-Based Analysis

Background: men who have sex with men (MSM) are a high-risk group for human papillomavirus (HPV) infection, and the HPV vaccine is effective in preventing it. However, according to risk compensation theory, people may increase sexual risk behaviors after receiving HPV vaccination. Based on the Health Action Process Approach (HAPA), this study investigated the influencing factors to predict intention to reduce condom use (risk compensation intention) among MSM after taking HPV vaccination in southwest China. Methods: we conducted a cross-sectional study among 948 MSM in southwest China using a non-probability sampling method and an electronic questionnaire including sociodemographic characteristics, sexual risk behavior characteristics, HPV-related prevention behavior, and the HAPA scale. Confirmatory factor analysis was performed using a structural equation model. Results: among 948 MSM, the incidence rate of reducing the frequency of condom use was 14.1%. The structural equation model showed that self-efficacy (β = -0.378, p = 0.020) and positive outcome expectancy (β = 0.366, p < 0.05) had greater effects on behavioral intention, followed by negative outcome expectancy (β = -0.296, p < 0.05) and risk perception (β = -0.232, p < 0.05). Conclusions: risk compensation may not be a major barrier to receiving HPV vaccination among MSM. Nevertheless, the recognition of possible risk compensation is necessary to implement appropriate interventions to reduce the occurrence of risk compensation.

High-risk human papillomavirus genotype distribution among women living with and at risk for HIV in Africa

OBJECTIVE

Cervical cancer is a common preventable cancer among African women living with HIV (WLWH). Molecular diagnostics for high-risk human papillomavirus (HR-HPV) genotypes are standard components of cervical cancer screening in resource-rich countries but not in resource-limited settings. We evaluated HR-HPV genotypes among women with and without HIV in four African countries to inform cervical cancer preventive strategies.

METHODS

The African Cohort Study (AFRICOS) enrolled participants with and without HIV at 12 clinics in Tanzania, Kenya, Uganda, and Nigeria. Cervical cytobrush specimens from women were genotyped for 14 HR-HPV types using the multiplex Seegene Anyplex real-time PCR assay. Robust Poisson regression was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for factors associated with HR-HPV in WLWH.

RESULTS

From January 2015 to March 2020, 868 WLWH and 134 women living without HIV (WLWoH) were tested for HR-HPV with prevalence of 50.9 and 38.1%, respectively ( P  = 0.007). Among WLWH, 844 (97.4%) were antiretroviral therapy (ART)-experienced and 772 (89.7%) virally suppressed 1000 copies/ml or less. The most frequent HR-HPV types among WLWH were HPV-16 (13.5%), HPV-52 (9.5%), and HPV-35 (9.3%). HR-HPV infection was more common among Tanzanian WLWH (adjusted RR: 1.23, 95% CI 1.05-1.44, P  = 0.012). Also, WLWH with CD4 + T cells of less than 200 cell/μl had 1.51-fold increased risk of having HR-HPV (95% CI 1.23-1.86, P  < 0.001).

CONCLUSION

HR-HPV was common in WLWH in four African countries, particularly among women with low CD4 + cell count. Scale up of HPV vaccines and development of vaccines with broader activity against less common HR-HPV types may improve cervical cancer prevention in Africa.

Malignancy and viral infections in Sub-Saharan Africa: A review

The burden of malignancy related to viral infection is increasing in Sub-Saharan Africa (SSA). In 2018, approximately 2 million new cancer cases worldwide were attributable to infection. Prevention or treatment of these infections could reduce cancer cases by 23% in less developed regions and about 7% in developed regions. Contemporaneous increases in longevity and changes in lifestyle have contributed to the cancer burden in SSA. African hospitals are reporting more cases of cancer related to infection (e.g., cervical cancer in women and stomach and liver cancer in men). SSA populations also have elevated underlying prevalence of viral infections compared to other regions. Of 10 infectious agents identified as carcinogenic by the International Agency for Research on Cancer, six are viruses: hepatitis B and C viruses (HBV and HCV, respectively), Epstein-Barr virus (EBV), high-risk types of human papillomavirus (HPV), Human T-cell lymphotropic virus type 1 (HTLV-1), and Kaposi's sarcoma herpesvirus (KSHV, also known as human herpesvirus type 8, HHV-8). Human immunodeficiency virus type 1 (HIV) also facilitates oncogenesis. EBV is associated with lymphomas and nasopharyngeal carcinoma; HBV and HCV are associated with hepatocellular carcinoma; KSHV causes Kaposi's sarcoma; HTLV-1 causes T-cell leukemia and lymphoma; HPV causes carcinoma of the oropharynx and anogenital squamous cell cancer. HIV-1, for which SSA has the greatest global burden, has been linked to increasing risk of malignancy through immunologic dysregulation and clonal hematopoiesis. Public health approaches to prevent infection, such as vaccination, safer injection techniques, screening of blood products, antimicrobial treatments and safer sexual practices could reduce the burden of cancer in Africa. In SSA, inequalities in access to cancer screening and treatment are exacerbated by the perception of cancer as taboo. National level cancer registries, new screening strategies for detection of viral infection and public health messaging should be prioritized in SSA's battle against malignancy. In this review, we discuss the impact of carcinogenic viruses in SSA with a focus on regional epidemiology.

HPV genotyping in biopsies of HSIL and invasive cervical cancers in women living with HIV: A cohort- and a nested -case control study

OBJECTIVE

To characterize HPV genotype distribution in HSIL and ICC- biopsies, of WLWH, in Europe, as compared to HIV-negative women.

DESIGN

Cohort- and nested -case control study.

METHOD

We characterized HPV genotype distribution by performing PCR on HSIL and ICC biopsies from WLWH (n = 170); 85 cases were compared to 85 HIV-negative matched controls. The proportion of patients that might be protected by HPV vaccines was estimated.

RESULTS

Among WLWH (median age 36 years-old, median duration of HIV infection 70,5 months, 79% under cART): the most frequently detected HPV were HPV16 (30%), HPV35 (16%), HPV58 (14,7%), HPV31 (13,5%), and HPV52 (11,7%). HPV16 was less frequently found in WLWH, originating from Central Africa (20,5%) compared to other African regions (35,5%) (p = 0,05) or world regions (38,8%) (p = 0,007). Multiple versus single high-risk HPV infections were associated with younger age (≤35 years)(odds ratio (OR) 2,65 (95%IC: 1,3-5,2,p = 0,002), lymphocyte CD4 count < 350 cells / µL (OR 2,7 (95%IC: 2-8,5; p = 0,005), use of cART for < 18 month OR 2,2 (95%IC: 1,1-4,5),p = 0,04) or a cumulative time with undetectable HIV viral load of less than 12 months (OR 4,2 (95%IC: 2-8.5,p = 0,001). HPV 31, 33 and 35 were more frequently detected in samples from WLWH than in HIV-negative controls (p < 0,05). The 9-valent vaccine would increase HPV protection, in HIV-positive and negative women (p < 0,001).

CONCLUSION

WLWH are more frequently infected with high-risk HPV other than 16 and 18 than HIV-negative ones. The use of 9-valent vaccine may prevent HSIL or ICC in up to 85% of the women. Adding HPV 35 to the HPV vaccine panel, might improve vaccine effectiveness in WLWH.

Update on the Epidemiological Features and Clinical Implications of Human Papillomavirus Infection (HPV) and Human Immunodeficiency Virus (HIV) Coinfection

Human papillomavirus (HPV) infection is the most common sexually transmitted infection (STI) worldwide. Although most HPV infections will spontaneously resolve, a considerable proportion of them will persist, increasing the risk of anogenital dysplasia, especially within certain populations, such as patients infected with human immunodeficiency virus (HIV). Furthermore, high-risk oncogenic HPV types (HR-HPV) are the main cause of cervix and other anogenital cancers, such as cancer of the vagina, vulva, penis, or anus. HIV and HPV coinfection is common among people living with HIV (PLWH) but disproportionally affects men who have sex with men (MSM) for whom the rate of persistent HPV infection and reinfection is noteworthy. The molecular interactions between HIV and HPV, as well as the interplay between both viruses and the immune system, are increasingly being understood. The immune dysfunction induced by HIV infection impairs the rate of HPV clearance and increases its oncogenic risk. Despite the availability of effective antiretroviral therapy (ART), the incidence of several HPV-related cancers is higher in PLWH, and the burden of persistent HPV-related disease has become a significant concern in an aging HIV population. Several public health strategies have been developed to reduce the transmission of HIV and HPV and mitigate the consequences of this type of coinfection. Universal HPV vaccination is the most effective preventive tool to reduce the incidence of HPV disease. In addition, screening programs for HPV-related cervical and vulvovaginal diseases in women are well-recognized strategies to prevent cervical cancer. Similarly, anal dysplasia screening programs are being implemented worldwide for the prevention of anal cancer among PLWH. Herein, the main epidemiological features and clinical implications of HIV and HPV coinfection are reviewed, focusing mainly on the relationship between HIV immune status and HPV-related diseases and the current strategies used to reduce the burden of HPV-related disease.

High-risk human papillomavirus infection among women living with HIV in Latin America and the Caribbean: A systematic review and meta-analysis

We carried out a systematic review to summarize available data regarding prevalence of high-risk human papillomavirus (HR-HPV) among women living with HIV (WLHIV) in Latin America and the Caribbean (LAC). A literature search in PubMed and LILACS was conducted and supplemented with cross-referencing and grey literature. The primary outcome was prevalence of HR-HPV by age as a major determinant of HPV infection. Pooled prevalence and weighted averages were obtained. A random effects meta-analysis conducted for HPV- and HIV-associated factors. In total, 6157 women from 19 cross-sectional studies were included. Weighted prevalence of HR-HPV in WLHIV was 51.0% (95% CI 42.8-59.1, I2 = 97.4%) with a bimodal trend by age. No association between antiretroviral therapy and HR-HPV prevalence was observed, but low CD4 cell count was associated (PR 1.64, 95% CI 1.07-2.52). Although not significant, a higher HR-HPV prevalence was observed with Hybrid Capture 2 versus PCR. The high prevalence of HR-HPV among WLHIV in LAC underlines the need for improved cervical cancer prevention and early detection in this vulnerable population. Moreover, the high prevalence across age groups, and particularly in young women, deserves careful consideration for defining target populations of HPV-based screening and HPV immunization programs.

Cervical cancer prevention and control in women living with human immunodeficiency virus

Despite being highly preventable, cervical cancer is the fourth most common cancer and cause of cancer death in women globally. In low-income countries, cervical cancer is often the leading cause of cancer-related morbidity and mortality. Women living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome are at a particularly high risk of cervical cancer because of an impaired immune response to human papillomavirus, the obligate cause of virtually all cervical cancers. Globally, approximately 1 in 20 cervical cancers is attributable to HIV; in sub-Saharan Africa, approximately 1 in 5 cervical cancers is due to HIV. Here, the authors provide a critical appraisal of the evidence to date on the impact of HIV disease on cervical cancer risk, describe key methodologic issues, and frame the key outstanding research questions, especially as they apply to ongoing global efforts for prevention and control of cervical cancer. Expanded efforts to integrate HIV care with cervical cancer prevention and control, and vice versa, could assist the global effort to eliminate cervical cancer as a public health problem.

Respective prevalence of high-risk HPVgenotypes in cervical neoplasia in Senegal

OBJECTIVES

With the perspective of prophylactic vaccination against high-risk human papillomavirus (HPV), we analyzed the viral epidemiology of cervical neoplasia in Senegal.

METHODS

All patients were treated at the Institut Joliot Curie du Cancer in Dakar. HPV genotypes were characterized using a real-time polymerase chain reaction-based approach and sequencing.

RESULTS

Histologically, there were 224 invasive carcinomas, 17 high-grade intraepithelial neoplasia (CIN), and five undetermined histologies. Molecular analysis was conclusive in 241 cases. HPV DNA was found in 207/241 (85.9%) cases while 34/241 (14.1%) remained HPV negative. There was one single genotype in 127/207 (61.4%) cases and several in 80/207 (38.6%) corresponding to 308 genotypes identified. Viral genotyping found HPV16 in 175 (56.8%) cases, HPV18 in 45 (14.6%), HPV45 in 40 (13.0%), HPV58 in 35 (11.4%), HPV33 in 6 (2.0%), HPV35 in 3 (1.0%), HPV31 in 2 (0.6%), HPV39 and HPV56 in one (0.3% each).

CONCLUSION

Our analysis showed that 98.4% of the HPV-positive cases were associated with viral genotypes covered by the 9-valent HPV vaccine. However, 14.1% of cases remained HPV negative. Therefore, prophylactic vaccination using a 9-valent vaccine should dramatically reduce the incidence of HPV-associated neoplasia but the detection and treatment of CIN remain necessary for the optimal prevention of cervical cancer.

Epidemiology and Burden of Human Papillomavirus and Related Diseases, Molecular Pathogenesis, and Vaccine Evaluation

Diagnosed in more than 90% of cervical cancers, the fourth deadliest cancer in women, human papillomavirus (HPV) is currently the most common pathogen responsible for female cancers. Moreover, HPV infection is associated with many other diseases, including cutaneous and anogenital warts, and genital and upper aerodigestive tract cancers. The incidence and prevalence of these pathologies vary considerably depending on factors including HPV genotype, regional conditions, the study population, and the anatomical site sampled. Recently, features of the cervicovaginal microbiota are found to be associated with the incidence of HPV-related diseases, presenting a novel approach to identify high-risk women through both blood and cervical samples. Overall, the HPV repartition data show that HPV infection and related diseases are more prevalent in developing countries. Moreover, the available (2-, 4-, and 9-valent) vaccines based on virus-like particles, despite their proven effectiveness and safety, present some limitations in terms of system development cost, transport cold chain, and oncogenic HPV variants. In addition, vaccination programs face some challenges, leading to a considerable burden of HPV infection and related diseases. Therefore, even though the new (9-valent) vaccine seems promising, next-generation vaccines as well as awareness programs associated with HPV vaccination and budget reinforcements for immunization are needed.

Role of polycyclic aromatic hydrocarbons as a co-factor in human papillomavirus-mediated carcinogenesis

BACKGROUND

Human papillomavirus (HPV) is an etiological agent of cervical cancer. Yet co-factors are believed to be involved in HPV-mediated carcinogenesis. Polycyclic aromatic hydrocarbons (PAHs) are considered as one of these co-factors. Epidemiologic studies have associated high PAH exposure with increased risk for cancer development. To date, many studies focus on benzo[a]pyrene, however, the role of other PAHs should not be neglected. This study aimed to compare the potential of different PAHs as a co-factor in HPV-mediated carcinogenesis, and to investigate the possible mechanisms involved.

METHODS

The effect of 17 PAHs on high-risk HPV (HPV16) were examined in this study. HPV16 E7 oncogene was expressed in primary cells extracted from baby rat kidney and treated with PAHs. The co-transforming ability of PAHs were measured by colony formation index according to the number and size of transformed colonies. Effects of PAHs on proliferation of HPV-null (C33A) and -infected (CaSki) were examined using CCK-8 assay. Wound healing assay and matrigel invasion chambers were used to investigate effects of PAHs on cell motility and invasivion of HPV-null (MCF7, C33A) and -infected (SiHa) cells.

RESULTS

Benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBA) and indeno[1,2,3-cd]pyrene (IDP) showed the greatest co-transforming potential in the baby rat kidney cell system. Short-term exposure to BaP, DBA, IDP and pyrene (PR) did not affect proliferation of C33A or CaSki cells, however, long-term exposure of these four PAHs led to dramatic increase in growth rate of CaSki cells by 120-140%. Besides, exposure of PAHs has an effect on cell motility and invasiveness of C33A and SiHa cells, but not for MCF7 cells. Exposure of BaP and DBA enhanced migration (1.26 to 1.40-fold) and invasion (1.68 to 1.94-fold) capacity of C33A cells. Intriguingly, exposure of all four types of PAHs boosted the migration (1.12 to 1.28-fold) and invasion (1.26 to 1.40-fold) capacity of SiHa cells.

CONCLUSIONS

Our results indicate that exposure to PAHs can be a key co-factor in HPV-related cancer development. They could act on all three stages, namely initiation, promotion and progression. Further study is needed to unveil the mechanisms by which PAHs interact with HPV to cause malignancy.