CHAPTER 7 Methods for detection of HPV infection and its clinical utility

Highly sensitive and specific detection of human papillomavirus type 16 using CRISPR/Cas12a assay coupled with an enhanced single nanoparticle dark-field microscopy imaging technique

Human papillomavirus (HPV) is a prevalent sexually transmitted pathogen associated with cervical cancer. Detecting high-risk HPV (hr-HPV) infections is crucial for cervical cancer prevention, particularly in resource-limited settings. Here, we present a highly sensitive and specific sensor for HPV-16 detection based on CRISPR/Cas12a coupled with enhanced single nanoparticle dark-field microscopy (DFM) imaging techniques. Ag-Au satellites were assembled through the hybridization of AgNPs-based spherical nucleic acid (Ag-SNA) and AuNPs-based spherical nucleic acid (Au-SNA), and their disassembly upon target-mediated cleavage by the Cas12a protein was monitored using DFM for HPV-16 quantification. To enhance the cleavage efficiency and detection sensitivity, the composition of the ssDNA sequences on Ag-SNA and Au-SNA was optimized. Additionally, we explored using the SynSed technique (synergistic sedimentation of Brownian motion suppression and dehydration transfer) as an alternative particle transfer method in DFM imaging to traditional electrostatic deposition. This addresses the issue of inconsistent deposition efficiency of Ag-Au satellites and their disassembly due to their size and charge differences. The sensor achieved a remarkable limit of detection (LOD) of 10 fM, lowered by 9-fold compared to traditional electrostatic deposition methods. Clinical testing in DNA extractions from 10 human cervical swabs demonstrated significant response differences between the positive and negative samples. Our sensor offers a promising solution for sensitive and specific HPV-16 detection, with implications for cancer screening and management.

Human Papillomavirus Infection and Oropharyngeal and Gastrointestinal Cancers: A Causal Relationship?

The human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide. The risk of being infected at least once in a lifetime among both men and women is estimated to be 50%. Although the majority of HPV infections are asymptomatic and improve within 2 years, approximately 10% of individuals develop a persistent infection and have an increased risk of developing carcinomas. The association of HPV and genital cancer is well established. However, there is evidence that HPV may also be associated with other cancers, including those of the gastrointestinal system. The aim of this review is to organize the current evidence of associations between HPV infections and oropharyngeal and gastrointestinal cancers, including the following: oropharyngeal, esophageal, gastric, colorectal, and anal cancers. A comprehensive review of the most up-to-date medical literature concluded that an HPV infection might have a role in the oncogenesis of gastrointestinal tract cancers. HPV may have a causal relationship with oropharyngeal and esophageal squamous cell cancers. However, the association between HPV and gastric and colorectal cancers is weaker. The development of cancer in the oropharyngeal and gastrointestinal tract is usually multifactorial, with HPV having a role in at least a subset of these cancers. HPV infections pose a big challenge due to their burden of infection and their oncogenic potential.

Acceptability, simplicity, and relevance of the new human papillomavirus/DNA test among 35-year-old ever-married women in a district of Sri Lanka: focus group discussions

Background

Two major drawbacks of the present cervical cancer screening programme in Sri Lanka are, the suboptimal sensitivity of the pap smear and the low coverage. The sensitivity of the HPV/DNA screening test is high. The objective of the study was to explore the acceptability relevance and simplicity of the new HPV/DNA screening implementation among ever-married women in a district of Sri Lanka.

Methods

Focus group discussions (FGD) (n = 3) in the public health divisions of the Kalutara district were used to collect data during December 2018. The study population comprised of ever-married women 35 years old, who, carried out an HPV/DNA test at a community Well Woman Clinics (WWCs) (n = 89). A list of WWCs was prepared according to an alphabetical order under urban, rural, and estate sector categories and allocated a number. One WWC was selected from each sector randomly for the three FGDs representing the estate, rural, and urban clinics. A convenient sampling technique was used to select participants for each FGD (n = 8). The information collected at each interview was summarized at the end of each interview. The analysis was done with manual content.

Results

Most of the participants were Sinhalese (n = 17, 70.9%), Buddhist (n = 18, n = 75%), and non-working (n = 18, n = 75%). The community awareness of HPV/DNA screening and field staff performance were highly appreciated by most of the participants. Most were aware of the high sensitivity of the HPV/DNA test, therefore the early detection rate of cervical cancer precursors is high. Most of the participants expressed the HPV/DNA test as a convenient and neutral test. Most were mentioned the necessity of repeated clinic visits for the pap test and colposcopy in HPV/DNA screened positive follow-up but there was marked acceptability (n = 23, 95.8%) for HPV/DNA test.

Conclusions

Acceptability of the new HPV/DNA screening test was high. Most of the participants perceived the HPV/DNA test to be simple and also relevant. Therefore, the HPV/DNA screening test can be recommended to be incorporated into the National Cervical Cancer Screening Programme as its suitability was well explored in the Sri Lankan setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-022-01712-2.

Designing a sequence-based method for identifying 14 high-risk carcinogenic HPV types in multiple infections

BACKGROUND

HPV tests have significant drawbacks in terms of detecting and differentiating types of the virus. PCR techniques provide timely and necessary results for patient care with high quality, sensitivity, and reasonable cost.

METHODS

The sensitivity of PCR depends on the primers. In this study, a method was designed that exploited PCR with designed primers (ScTd) by changing the annealing temperature (Ta) along with Sanger sequencing for pap smear samples. Sanger sequencing has confirmed that ScTd primers have a relative differentiation power using PCR. The primers caused a relative differentiation by PCR. In the pap smear sample 22 with contamination of types 16, 31, and 45, confirmed by dot blot hybridization, type 16 was not amplified at the specific Ta. Moreover, the band was observed at low Ta.

RESULTS

Sanger sequencing showed that type 16 was detected instead of type 52. Sequencing the heterozygous bands in multiple infections also led to the identification of different types. Moreover, with a combination of 7 pairs of primers, HPV types can be detected in multiple infections by PCR.

CONCLUSIONS

As compared with the clinical dot blot hybridization technique, the utilization of complementary PCR and sequencing methods with designed primers can provide a higher positive predictive value in the detection of high-risk types.

Molecular markers for cervical cancer screening

INTRODUCTION

Cervical cancer remains a significant healthcare problem, notably in low- to middle-income countries. While a negative test for hrHPV has a predictive value of more than 99.5%, its positive predictive value is less than 10% for CIN2+ stages. This makes the use of a so-called triage test indispensable for population-based screening to avoid referring women, that are ultimately at low risk of developing cervical cancer, to a gynecologist. This review will give an overview of tests that are based on epigenetic marker panels and protein markers.

AREAS COVERED

There is a medical need for molecular markers with a better predictive value to discriminate hrHPV-positive women that are at risk of developing cervical cancer from those that are not. Areas covered are epigenetic and protein markers as well as health economic considerations in view of the fact that most cases of cervical cancer arise in low-to-middle-income countries.

EXPERT OPINION

While there are biomarker assays based on changes at the nucleic acid (DNA methylation patterns, miRNAs) and at the protein level, they are not widely used in population screening. Combining nucleic acid-based and protein-based tests could improve the overall specificity for discriminating CIN2+ lesions that carry a low risk of progressing to cervical cancer within the screening interval from those that carry an elevated risk. The challenge is to reduce unnecessary referrals without an undesired increase in false-negative diagnoses resulting in cases of cervical cancer that could have been prevented. A further challenge is to develop tests for low-and middle-income countries, which is critical to reduce the worldwide burden of cervical cancer.

Next-generation sequencing for typing human papillomaviruses and predicting multi-infections and their clinical symptoms

Human papillomavirus (HPV) has more than 100 different types, some of which are associated with cancer. The most common example is that of cervical cancer, which is associated with HPV16 and HPV18. Here, we performed next-generation sequencing (NGS) to type 2436 samples obtained from Korean women to elucidate the correlation between multiple infections, virus types, and cytology. NGS revealed that types 58, 56, and 16 were the most common in high-risk (HR) types, whereas types 90, 54, and 81 were the most common in low-risk (LR) types. The incidence of atypical squamous cells of undetermined significance (ASCUS) or high-grade squamous intraepithelial lesion (HSIL) was 11.45% in single-type cases and 27.17% in multiple infections by the two types of HPV. ASCUS or HSIL was 29.79% in only the HR type multiple infections and 29.81% in mixed high- and low-risk types of multiple infections, whereas it was 18.79% in LR type multiple infections (P ≤ 0.0001). Co-infection by LR-HPV and HR-HPV is therefore more likely to cause cell lesions. Collectively, these results show that the higher the incidence of multiple infections, the greater the frequency of cell lesions. Thus, to predict the clinical symptoms, it would be beneficial to confirm the HPV type and multiple infections using NGS, although this could be relatively expensive.

HPV-Negative Cervical Cancer: A Narrative Review

Cervical cancer (CC) is the fourth most frequent cancer in women worldwide. HPV infection is associated with the majority of CC cases, but a small proportion of CCs actually test negative for HPV. The prevalence of HPV among CC histotypes is very different. It has been suggested that HPV-negative CC may represent a biologically distinct subset of tumors, relying on a distinct pathogenetic pathway and carrying a poorer prognosis, than HPV-positive CCs. Although, the discordance in terms of sensitivity and specificity between different HPV tests as well as the potential errors in sampling and storing tissues may be considered as causes of false-negative results. The identification of HPV-negative CCs is essential for their correct management. The aim of this narrative review is to summarize the clinical and pathological features of this variant. We also discuss the pitfalls of different HPV tests possibly leading to classification errors.

Human papilloma virus: A review study of epidemiology, carcinogenesis, diagnostic methods, and treatment of all HPV-related cancers

Background: Human papillomavirus (HPV) infection is considered as the most common viral sexually transmitted infection worldwide. This poses an increasingly interdisciplinary medical challenge. Since there is vast scattered information in databases about HPV and the correlated diseases, we decided to collect useful data so that the experts can get a more comprehensive view of HPV. Methods: In this article, HPV-associated diseases, prevalence, prevention, and new treatments are discussed. The retrieved articles reporting the latest data about the required information for our review were selected through searching in Web of Science, Scopus, Medline (PubMed), EMBASE, Cochrane Library, Ovid, and CINHAL with language limitations of English and German. Results: There are 2 groups of HPVs: (1) low-risk HPV types that can lead to genital warts, and (2) high-risk HPV types that are involved in HPV-associated oncogenesis. About 70% of all sexually active women are infected and most of these infections heal within many weeks or months. In the case of HPV-persistence, a risk of preneoplasia or carcinoma exists. These types of viruses are responsible for the existence of genitoanal, gastrointestinal, urinary tract, and head and neck tumors. There is still no definite successful treatment. The detection of HPV-related condylomata occurs macroscopically in women and men, and the diagnosis of the precursors of cervical carcinoma in women is possible by Pap smear. Conclusion: For extragenital manifestations, there is no structured early detection program. Meanwhile, studies on HPV vaccines confirm that they should be used for the primary prevention of HPV-dependent diseases. However, we need more research to find out the real advantages and disadvantages of vaccines.

PCR-RFLP and FTIR-based detection of high-risk human papilloma virus for cervical cancer screening and prevention

Background

Approximately 70% of cervical carcinoma cases show the presence of high-risk Human Papilloma Virus (HPV), especially HPV-16 and HPV-18, and can be used to stratify high risk patients from low risk and healthy. Currently, molecular biology techniques such as polymerase chain reaction (PCR) are used to identify the presence of virus in patient samples. While the methodology is highly sensitive, it is labor intensive and time-consuming. Alternative techniques, such as vibrational spectroscopy, has been suggested as a possible rapid alternative. Therefore, in this study, we evaluate the efficiency of cervical fluid Fourier Transform Infrared spectroscopy (FTIR) in patient risk stratification informed by PCR.

Methods

Cervical fluid samples (n = 91) were obtained from patients who have undergone routine Papanicolaou (Pap) test. Viral genome was identified and classified as high/low-risk by PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). FTIR spectra were acquired from samples identified by PCR-RFLP as No-HPV (n = 10), high-risk HPV (n = 7), and low-risk HPV (n = 7).

Results

Of the 91 samples, was detected the viral genome by PCR in 36 samples. Of these 36 samples, nine samples were identified to contain high-risk HPV (HR-HPV) and nine samples were found to have low-risk HPV (LR-HPV). The FTIR spectra acquired from No-HPV, LR-HPV, and HR-HPV showed differences in 1069, 1437, 1555, 1647, 2840, 2919, and 3287 cm^-1 bands. Principal Component Analysis (PCA) showed distinct clusters for No-HPV and HR-HPV and No-HPV and LR-HPV, but there was significant overlap in the clusters of HR-HPV and LR-HPV. PCA-Linear Discriminant Analysis (PC-LDA) after Leave One Out Cross Validation (LOOCV) classified No-HPV from HR-HPV and No-HPV from LR-HPV with 100% efficiency in the 1400-1800 cm^-1 spectral range. LOOCV classifications for LR-HPV and HR-HPV from each other were 71 and 75%, respectively, in the 2800-3400 cm^-1 spectral range.

Conclusions

The results highlight the high sensitivity of PCR-RFLP in HPV identification and show that FTIR can classify samples identified as healthy, low, and high-risk samples by PCR-RFLP.

General significance

We show the possibility of using FTIR for initial cervical cancer risk stratification followed by detailed PCR-RFLP investigations for suspect cases.

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Molecular biology showed high sensitivity and specificity in HPV detection compared with cytological analysis.

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PCR-RFLP technique identify high-risk variants of HPV can significantly assist in the prevention of cervical cancer.

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PC-LDA and LOOCV classified normal from high-risk HPV and normal from low-risk HPV with 100% efficiency.

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FTIR can be used for initial cervical cancer risk stratification followed by more detailed investigations by PCR-RFLP.

A Retrospective Study about the Impact of Switching from Nested PCR to Multiplex Real-Time PCR on the Distribution of the Human Papillomavirus (HPV) Genotypes

Background and objectives: Human papillomavirus (HPV) is the most prevalent etiological agent of viral sexually-transmitted infection. This study retrospectively evaluated the impact of a switch to a real-time PCR assay in the HPV prevalence and genotypes distribution by a quasi-experimental before-and-after approach. Materials and Methods: In total, 1742 samples collected from 1433 patients were analyzed at the UOC Microbiology and Virology of Policlinico of Bari, Italy. HPV DNA detection was performed using initially nested PCR and subsequently multiplex real-time PCR assay. Results: Statistically significant difference in HPV overall prevalence after the introduction of the real-time assay was not detected (48.97% vs. 50.62%). According to different extraction-DNA amplification methods, differences were observed in the prevalence rates of HPV-45, 68, 40, 42, and 43. The lowest prevalence for HPV-45 was observed in the Magna Pure-Real Time PCR group, while HPV-68, 40, 42, and 43 were less observed in the Qiagen-Real Time PCR group. After, a multivariate logistic regression, an increase in the prevalence of HPV-42 (aOR: 4.08, 95% CI: 1.71–9.73) was associated with the multiplex real-time PCR assay. Conclusions: Although this study is a not a direct comparison between two diagnostic methods because it has a sequential structure, it serves to verify the impact of a new molecular assay on HPV distribution. Moreover, the stability of HPV prevalence over time suggests that the population composition and the behavioral variables did not likely change during the observation period. Our study proposes that the introduction of a molecular test for HPV detection may be related to changes of HPV genotypes distribution.

TiO2 nanowires as an effective sensing platform for rapid fluorescence detection of single-stranded DNA and double-stranded DNA

Numerous nanomaterials have been utilized for novel biosensors with sensitivity and selectivity in the last decades due to their intrinsic unique properties. Herein, a facile fluorescence method for nucleic acid detection was developed by employing TiO₂ nanowires (NWs) as the sensing platform. The quenching effect of TiO₂ NWs to fluorophore-labelled single-stranded DNA (ssDNA) was found to be more significant than that to fluorophore-labelled double-stranded DNA (dsDNA) or triplex DNA probes. More importantly, the whole quenching process was also fast since it just took about ten minutes to reach the equilibrium. Based on the different affinities of TiO₂ NWs to ssDNA, dsDNA and triplex DNA probes, the sequence-specific nucleic acids were detected with sensitivity and specificity. Further investigation has demonstrated that the quenching efficiency of TiO₂ NWs to long ssDNA was apparently superior than that to short ssDNA. Moreover, the fluorescence from various ssDNA probes labelled with a wide spectrum of fluorescent dyes could also be quenched by TiO₂ NWs. These inspiring results reveal that TiO₂ NWs could be an excellent universal nanoquencher used in the next-generation biosensors.

Human papillomaviruses' proteins with clinical utility

Cervical cancer, the fourth leading cause of cancer-associated deaths among women worldwide, is associated with human papilloma virus (HPV) infection. Despite the prophylactic HPV vaccination and the implementation of cervical and HPV-based screening programs, a significant increase in cervical cancer incidence is estimated by the year 2020. Thus, further development of diagnostic tools that allow detection and risk assesment in genital HPV infection is necessary. A special interest is focused on the HPV viral proteins whose expression might be of use either as primary screening tool or in conjunction with other markers (cellular proteins, HPV DNA, PAP test).

Prevalence characteristics of single and multiple HPV infections in women with cervical cancer and precancerous lesions in Beijing, China

We assessed the prevalence characteristics of single and multiple high-risk human papillomavirus (HR-HPV) infections. A total of 1783 women who underwent colposcopy and cervical biopsy for abnormal ThinPrep Cytology Test and/or HR-HPV subtype genotyping results were enrolled in the study. Among the participants, 770 were diagnosed with cervicitis, 395 with cervical intraepithelial neoplasia grade 1 (CIN1), 542 with CIN2-3, and 76 with squamous cell carcinoma (SCC), with HR-HPV infection rates of 75.8%, 85.8%, 95.9%, and 88.4%, respectively. The prevalence of total and multiple HR-HPV infections exhibited a bimodal age distribution with a peak at ≤25 years, a decline with age and a second peak at ≥55 years, whereas single HR-HPV infections exhibited one peak from 35 to 44 years. The four most dominant HPV genotypes were HPV 16 (29.5%), 52 (15.0%), 58 (14.2%), and 18 (10.4%). In total, 67.0%, 70.4%, and 82.1% of patients with CIN1, CIN2-3, and SCC, respectively, had a single HR-HPV infection, which increased significantly with the aggravation of the cervical lesion grade (P = 0.045). Patients with a single HPV 16 infection had higher incidences of CIN2+ (62.2%) than those with multiple HPV 16 infections (52.4%) (P = 0.021). Patients coinfected with HPV 16 had higher CIN2+ incidence than those with single HPV 52, 31, 33, 35, 39, 45, 51, 56, or 59 infections (P < 0.001). This study provided baseline data on the prevalence characteristics of single and multiple HR-HPV infections in women attending a gynecological outpatient clinic in Beijing.

Advancements in electrochemical DNA sensor for detection of human papilloma virus - A review

Human papillomavirus (HPV) is one of the most common sexually transmitted disease, transmitted through intimate skin contact or mucosal membrane. The HPV virus consists of a double-stranded circular DNA and the role of HPV virus in cervical cancer has been studied extensively. Thus it is critical to develop rapid identification method for early detection of the virus. A portable biosensing device could give rapid and reliable results for the identification and quantitative determination of the virus. The fabrication of electrochemical biosensors is one of the current techniques utilized to achieve this aim. In such electrochemical biosensors, a single-strand DNA is immobilized onto an electrically conducting surface and the changes in electrical parameters due to the hybridization on the electrode surface are measured. This review covers the recent developments in electrochemical DNA biosensors for the detection of HPV virus. Due to the several advantages of electrochemical DNA biosensors, their applications have witnessed an increased interest and research focus nowadays.

Multiplex Paper-Based Colorimetric DNA Sensor Using Pyrrolidinyl Peptide Nucleic Acid-Induced AgNPs Aggregation for Detecting MERS-CoV, MTB, and HPV Oligonucleotides

The development of simple fluorescent and colorimetric assays that enable point-of-care DNA and RNA detection has been a topic of significant research because of the utility of such assays in resource limited settings. The most common motifs utilize hybridization to a complementary detection strand coupled with a sensitive reporter molecule. Here, a paper-based colorimetric assay for DNA detection based on pyrrolidinyl peptide nucleic acid (acpcPNA)-induced nanoparticle aggregation is reported as an alternative to traditional colorimetric approaches. PNA probes are an attractive alternative to DNA and RNA probes because they are chemically and biologically stable, easily synthesized, and hybridize efficiently with the complementary DNA strands. The acpcPNA probe contains a single positive charge from the lysine at C-terminus and causes aggregation of citrate anion-stabilized silver nanoparticles (AgNPs) in the absence of complementary DNA. In the presence of target DNA, formation of the anionic DNA-acpcPNA duplex results in dispersion of the AgNPs as a result of electrostatic repulsion, giving rise to a detectable color change. Factors affecting the sensitivity and selectivity of this assay were investigated, including ionic strength, AgNP concentration, PNA concentration, and DNA strand mismatches. The method was used for screening of synthetic Middle East respiratory syndrome coronavirus (MERS-CoV), Mycobacterium tuberculosis (MTB), and human papillomavirus (HPV) DNA based on a colorimetric paper-based analytical device developed using the aforementioned principle. The oligonucleotide targets were detected by measuring the color change of AgNPs, giving detection limits of 1.53 (MERS-CoV), 1.27 (MTB), and 1.03 nM (HPV). The acpcPNA probe exhibited high selectivity for the complementary oligonucleotides over single-base-mismatch, two-base-mismatch, and noncomplementary DNA targets. The proposed paper-based colorimetric DNA sensor has potential to be an alternative approach for simple, rapid, sensitive, and selective DNA detection.

Low prevalence of human papillomavirus in head and neck squamous cell carcinoma in the northwest region of the Philippines

BACKGROUND

Geographic heterogeneity of human papillomavirus (HPV) involvement in head and neck squamous cell carcinoma (HNSCC) has been observed over the last few years. This trend has not been evaluated in the Philippines. Hence, this study aims to provide for the first time a data on the prevalence of HPV in HNSCC in the northwestern region of the Philippines.

METHODS

Two hundred one (201) biopsy samples (179 formalin fixed paraffin embedded and 22 fresh frozen) from 163 Filipino HNSCC cases (oral cavity = 88; larynx = 60; oropharynx = 15) diagnosed between 2003 to 2013 were initially included in this study. HPV DNA was detected by two methods: (1) BSGP5+/6+-PCR/ multiplex human papillomavirus genotyping and (2) TaqMan probes-based real-time qPCR. Presence of HPV type-specific transcripts were also analyzed by reverse transcription-PCR with subsequent hybridization to oligonucleotide probes coupled to Luminex beads. Co-amplification of the β-globin and ubiquitin C genes served as internal positive controls for DNA and RNA analyses, respectively.

RESULTS AND CONCLUSIONS

Of the 163, 82 (50.3%) cases had at least one tissue sample that was valid for molecular analysis. Only two of the DNA valid cases (2.4%) were HPV DNA-positive (HPV11 and HPV33). All HPV mRNA assays rendered negative results except for HPV11 transcripts. Results of this study may indicate that there is probably very low prevalence of HPV-associated HNSCC among Filipino adults living in a rural region of the Philippines. This study could serve as a benchmark for designing follow-up studies that would assess possible changes in trends of HNSCC among Filipinos in different ethnic regions of the country, especially urban areas in which the population is expected to adapt Western style sexual behavior. A prospective sampling of fresh frozen tissue is also highly recommended to ensure better molecular analyses.

Comparison of DNA testing strategies in monitoring human papillomavirus infection prevalence through simulation

BACKGROUND

HPV DNA diagnostic tests for epidemiology monitoring (research purpose) or cervical cancer screening (clinical purpose) have often been considered separately. Women with positive Linear Array (LA) polymerase chain reaction (PCR) research test results typically are neither informed nor referred for colposcopy. Recently, a sequential testing by using Hybrid Capture 2 (HC2) HPV clinical test as a triage before genotype by LA has been adopted for monitoring HPV infections. Also, HC2 has been reported as a more feasible screening approach for cervical cancer in low-resource countries. Thus, knowing the performance of testing strategies incorporating HPV clinical test (i.e., HC2-only or using HC2 as a triage before genotype by LA) compared with LA-only testing in measuring HPV prevalence will be informative for public health practice.

METHOD

We conducted a Monte Carlo simulation study. Data were generated using mathematical algorithms. We designated the reported HPV infection prevalence in the U.S. and Latin America as the "true" underlying type-specific HPV prevalence. Analytical sensitivity of HC2 for detecting 14 high-risk (oncogenic) types was considered to be less than LA. Estimated-to-true prevalence ratios and percentage reductions were calculated.

RESULTS

When the "true" HPV prevalence was designated as the reported prevalence in the U.S., with LA genotyping sensitivity and specificity of (0.95, 0.95), estimated-to-true prevalence ratios of 14 high-risk types were 2.132, 1.056, 0.958 for LA-only, HC2-only, and sequential testing, respectively. Estimated-to-true prevalence ratios of two vaccine-associated high-risk types were 2.359 and 1.063 for LA-only and sequential testing, respectively. When designated type-specific prevalence of HPV16 and 18 were reduced by 50 %, using either LA-only or sequential testing, prevalence estimates were reduced by 18 %.

CONCLUSION

Estimated-to-true HPV infection prevalence ratios using LA-only testing strategy are generally higher than using HC2-only or using HC2 as a triage before genotype by LA. HPV clinical testing can be incorporated to monitor HPV prevalence or vaccine effectiveness. Caution is needed when comparing apparent prevalence from different testing strategies.

Human papillomavirus genotype distribution and E6/E7 oncogene expression in Turkish women with cervical cytological findings

BACKGROUND

Infection with certain human papillomavirus (HPV) genotypes is the most important risk factor related with cervical cancer. The objective of the present study was to investigate the prevalence of HPV infection, the distribution of HPV genotypes and HPV E6/E7 oncogene mRNA expression in Turkish women with different cervical cytological findings in Mersin province, Southern Turkey.

MATERIALS AND METHODS

A total of 476 cytological samples belonging to women with normal and abnormal cervical Pap smears were enrolled in the study. For the detection and genotyping assay, a PCR/direct cycle sequencing approach was used. E6/E7 mRNA expression of HPV-16, 18, 31, 33, and 45 was determined by type-specific real-time NASBA assay (NucliSENS EasyQ(®)HPV v1.1).

RESULTS

Of the 476 samples, 106 (22.3%) were found to be positive for HPV DNA by PCR. The presence of HPV was significantly more common (p<0.001) in HSIL (6/8, 75%) when compared with LSIL (6/14, 42.9%), ASC-US (22/74, 29.7%) and normal cytology (72/380, 18.9%). The most prevalent genotypes were, in descending order of frequency, HPV genotype 66 (22.6%), 16 (20.8%), 6 (14.2%), 31 (11.3%), 53 (5.7%), and 83 (4.7%). HPV E6/E7 oncogene mRNA positivity (12/476, 2.5%) was lower than DNA positivity (38/476, 7.9%).

CONCLUSIONS

Our data present a wide distribution of HPV genotypes in the analyzed population. HPV genotypes 66, 16, 6, 31, 53 and 83 were the predominant types and most of them were potential carcinogenic types. Because of the differences between HPV E6/E7 mRNA and DNA positivity, further studies are required to test the role of mRNA testing in the triage of women with abnormal cervical cytology or follow up of HPV DNA positive and cytology negative. These epidemiological data will be important to determine the future impact of vaccination on HPV infected women in our region.

Molecular Detection and Typing of Human Papillomaviruses in Paraffin-Embedded Cervical Cancer and Pre-Cancer Tissue Specimens

Background:

Cervical cancer is one of the important reasons of mortality among females. Prevention, early diagnosis and immediate treatment can affect the rate of mortality in this cancer and several epidemiological studies have shown a strong relationship between human papilloma viruses (HPVs) and cervical cancer.

Objectives:

The present study was conducted to survey HPV infections in a women population with cervical cancer and cervical dysplasia/metaplasia in southwest of Iran.

Materials and Methods:

72 paraffin-embedded cervical biopsies which had been previously archived from women with cervical cancer and cervical dysplasia were examined by polymerase chain reaction (PCR). Afterward, the detected HPV strains were typed by restriction fragment length polymorphism (RFLP) analysis of PCR amplicons.

Results:

60 out of 72 samples had necessary requirements and HPV DNA was detected in 43.3% of these samples. Most HPV positive samples belonged to women aged from 48 to 63 years. On the other hand, HPV infection among patients with squamous cell carcinoma (SCC) was 48.78% and in women with dysplasia/metaplasia was 26.66%. The most prevalent type of the human papilloma virus was HPV16 (100%).

Conclusions:

Knowing the most prevalent type of the human papilloma viruses circulating in the population (HPV16) can be applied in the future screening and managing programs of this major disease and also in vaccination against the prevalent types of the virus. Meanwhile, it seems that more studies should be performed to determine the role of different risk factors involved in development of the disease, especially those related with social behaviors and traditions with respect to different areas.

A fully integrated paperfluidic molecular diagnostic chip for the extraction, amplification, and detection of nucleic acids from clinical samples

Paper diagnostics have successfully been employed to detect the presence of antigens or small molecules in clinical samples through immunoassays; however, the detection of many disease targets relies on the much higher sensitivity and specificity achieved via nucleic acid amplification tests (NAAT). The steps involved in NAAT have recently begun to be explored in paper matrices, and our group, among others, has reported on paper-based extraction, amplification, and detection of DNA and RNA targets. Here, we integrate these paper-based NAAT steps into a single paperfluidic chip in a modular, foldable system that allows for fully integrated fluidic handling from sample to result. We showcase the functionality of the chip by combining nucleic acid isolation, isothermal amplification, and lateral flow detection of human papillomavirus (HPV) 16 DNA directly from crude cervical specimens in less than 1 hour for rapid, early detection of cervical cancer. The chip is made entirely of paper and adhesive sheets, making it low-cost, portable, and disposable, and offering the potential for a point-of-care molecular diagnostic platform even in remote and resource-limited settings.

Human papillomavirus prevalence and type-distribution among women in Zhejiang Province, Southeast China: a cross-sectional study

Background

Human papillomavirus (HPV) infection is the main etiological factor for cervical cancer and premalignant lesions of the cervix. The purposes of the present study were to determine the prevalence of type-specific HPV infections and the association of different HPV types with cervical dysplasia among women in Zhejiang province, Southeast China.

Methods

A total of 15,267 women presenting to a gynaecological outpatient clinic were enrolled in this study. Women were screened for HPV in addition to routine cervical cytology testing. Microarray hybridization and liquid-based cytology tests were used to detect HPV genotypes and cervical cytology, respectively.

Results

Based on the population attending a gynaecological outpatient clinic, overall prevalence of any 23 HPV type was 22.8% and multiple HPV infection was found in 4.0% of all the outpatients. HPV prevalence showed bimodal age distribution, with a peak (55.7%) at the ≤20 age group and a second one (35.5%) at >60 age group. In total samples, the five most frequent types were HPV 16 (4.4%), 58 (2.9%), 52 (2.7%), 33 (2.2%) and 11 (1.9%). Overall HPV prevalence increased with the severity of the cytologic result. Analysis through crude odds ratios (ORs) revealed that the cervical lesion risk of HPV-infected women increased to about 26-fold of uninfected women (OR 26.1, 95% CI 22.4 to 30.3). The five most risky HPV types associated with abnormal cytology were HPV 73, 16, 82, 45 and 51.

Conclusions

This study provided baseline data on HPV prevalence in women attending a gynecological outpatient clinic in Zhejiang province. Our data will supply guidance for the primary screening and vaccination program for cervical cancer in this area.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0708-8) contains supplementary material, which is available to authorized users.

The prevalence of precancerous cervical cancer lesion among HIV-infected women in southern Ethiopia: a cross-sectional study

Introduction

The magnitude of precancerous cervical cancer lesions as well as invasive cervical cancer is higher in HIV-infected women than non HIV-infected women. Thus, screening targeting HIV-infected women is being undertaken in developing countries, including Ethiopia. However, data on the prevalence and determinants of precancerous cervical cancer lesion among HIV-infected women in southern Ethiopia is lacking. Thus, this study aimed to assess the prevalence of and factors associated with precancerous cervical cancer lesion among HIV- infected women in southern Ethiopia.

Methods

A hospital-based cross-sectional study was conducted from October 2012 to February 2013 among HIV-infected women in Southern Ethiopia. Four hundred forty eight HIV-infected women who had been screened and treated for precancerous cervical cancer lesion were included in the study. Data were collected by using structured and pretested questionnaire. Visual inspection with acetic acid was applied for screening and treatment. SPSS version 16.0 was used for data entry and analysis. Logistic regression analysis was fitted and odds ratios with 95% Confidence intervals and p-values were computed to identify factors associated with precancerous cervical cancer lesion.

Results

Out of 448 study participants, 99 (22.1%) were found to be positive for precancerous cervical cancer. Being currently on highly active antiretroviral treatment (AOR=0.52, 95%CI: 0.35, 0.92), history of sexually transmitted disease (AOR=2.30, 95%CI: 1.23, 4.29) and having only one lifetime sexual partner (AOR=0.33, 95%CI: 0.20, 0.56) were factors associated with precancerous cervical cancer lesion.

Conclusions

The prevalence of precancerous cervical cancer lesion among HIV-infected women in southern Ethiopia was found to be high. Intervention to access all HIV-infected women like scaling up the limited services and awareness creation should be undertaken. Measures aimed at preventing the acquisition and transmission of sexually transmitted diseases and reducing the number of sexual partners are required. Besides, early initiation of highly active antiretroviral treatment is important.

Electrochemical detection of human papillomavirus DNA type 16 using a pyrrolidinyl peptide nucleic acid probe immobilized on screen-printed carbon electrodes

An electrochemical biosensor based on an immobilized anthraquinone-labeled pyrrolidinyl peptide nucleic acid (acpcPNA) probe was successfully developed for the selective detection of human papillomavirus (HPV) type 16 DNA. A 14-mer acpcPNA capture probe was designed to recognize a specific 14 nucleotide region of HPV type 16 L1 gene. The redox-active label anthraquinone (AQ) was covalently attached to the N-terminus of the acpcPNA probe through an amide bond. The probe was immobilized onto a chitosan-modified disposable screen-printed carbon electrode via a C-terminal lysine residue using glutaraldehyde as a cross-linking agent. Hybridization with the target DNA was studied by measuring the electrochemical signal response of the AQ label using square-wave voltammetric analysis. The calibration curve exhibited a linear range between 0.02 and 12.0 µM with a limit of detection and limit of quantitation of 4 and 14 nM, respectively. This DNA sensing platform was successfully applied to detect the HPV type 16 DNA from a PCR amplified (240 bp fragment of the L1 gene) sample derived from the HPV type 16 positive human cancer cell line (SiHa), and failed to detect the HPV-negative c33a cell line. The sensor probe exhibited very high selectivity for the complementary 14 base oligonucleotide over the non-complementary oligonucleotides with sequences derived from HPV types 18, 31 and 33. The proposed sensor provides an inexpensive tool for the early stage detection of HPV type 16, which is an important biomarker for cervical cancer.

Implications for human papillomavirus in penile cancer

Human papillomavirus infection (HPV) has been implicated in penile cancer, and although the annual incidence is estimated to be 1,570 in the United States, there are areas of the world in which the incidence is as much as 20-fold higher. Ample data in the literature support testing and vaccination against HPV-related cervical cancer, but for men and penile cancer, these data are lacking. However, some preliminary data would suggest that HPV not only plays an important role in a significant subset of patients with penile cancer but also may be a target for penile cancer prevention as well via initiation of a vaccination program in high-risk male populations.

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.

Langerhans cell density in cervical intraepithelial neoplasia associated with human papillomavirus infection in HIV-infected and HIV-noninfected Brazilian women

OBJECTIVE

Local immunity plays an important role in the cervical defense mechanisms that prevent the development of cervical intraepithelial neoplasia. The objective of this study was to determine the involvement of local immunity by evaluating Langerhans cell (LC) density in cervical biopsies of human immunodeficiency virus (HIV)-positive and HIV-negative women.

MATERIALS AND METHODS

A cross-sectional study was developed by including HIV-positive and HIV-negative women. All patients presented human papillomavirus DNA from the uterine cervix, which was detected by polymerase chain reaction or hybrid capture II. Cervical biopsies were assessed for LC density and cervical intraepithelial neoplasia. Langerhans cells were identified by immunohistochemistry using anti-CD1a and anti-S100 antibodies. Associations among cervical LC density, the type of cervical lesion, CD4 lymphocyte count, and HIV viral load were analyzed using logistic regression (SPSS, version 12.0).

RESULTS

Seventy-seven women (40 seropositive and 37 seronegative) were enrolled. The mean ± SD LC density identified with the anti-CD1a antibody was 0.80 ± 0.7 cells versus 2.6 ± 1.6 cells (P < 0.0001), whereas the mean ± SD LC density identified by the anti-S100 antibody was 1.3 ± 1.0 cells versus 3.6 ± 1.7 cells (P < 0.0001) among the HIV-positive and HIV-negative women, respectively. There were no associations between LC density and HIV viral load, CD4 lymphocyte count, or human papillomavirus genotype (P > 0.05). In a logistic regression model, HIV infection was the only factor independently associated with a decrease in LC density.

CONCLUSIONS

Human immunodeficiency virus infection was found to be an independent factor that explains the decrease in local immunity in the uterine cervix, which could allow the development of cervical lesions. This effect was not associated with CD4 lymphocyte count or HIV viral load.

The epidemiology and natural history of anal human papillomavirus infection in men who have sex with men

Studies on the epidemiology and natural history of anal human papillomavirus (HPV) infection are essential to understand the significance of this virus in the aetiology of anal cancer in men who have sex with men (MSM). This paper presents a review of studies on anal HPV in MSM. For this review, a Medline search was performed to identify English-language articles published in peer-reviewed journals on the epidemiology, natural history and risk factors for anal HPV infection in MSM. Anal HPV prevalence is high in MSM and infection with multiple HPV types is common. The available prospective data suggest detection of new anal HPV infections may also be common. However, with limited epidemiological data available on infection dynamics and associated behavioural risk factors, it is difficult to draw conclusions on how persistent anal HPV infection is in this population.

Unresolved questions concerning human papillomavirus infection and transmission: a modelling perspective

Mathematical transmission models are widely used to forecast the potential impact of interventions such as vaccination and to inform the development of health policy. Effective vaccines are now available for the prevention of cervical cancer and other diseases attributable to human papillomavirus (HPV). Considerable uncertainties remain regarding the characterisation of HPV infection and its sequelae, infectivity, and both vaccine-conferred and naturally-acquired immunity. In this review, we discuss the key knowledge gaps that impact on our ability to develop accurate models of HPV transmission and vaccination.

Innovation in cervical cancer prevention and control in Mexico

Disparities related to cervical cancer continue to exist in Mexico, including insufficient screening coverage, problems with quality control and a resulting greater risk of mortality among women from marginalized areas. A lack of opportunities and requirements for continuing education and accreditation of healthcare personnel involved in the screening program is also an issue. HPV DNA testing and HPV vaccines are recent technological innovations that offer a potential solution to the continued negative impact of cervical cancer among Mexican women. This essay attempts to answer questions such as: Why should HPV testing be integrated into the early detection program in Mexico? How can HPV testing best be integrated into the program in Mexico? How-from a public health perspective that seeks to reduce disparities-can HPV vaccination best be implemented in Mexico? HPV testing allows increased positive predictive value while also reducing costly and unnecessary overtreatment of low-grade abnormalities, and HPV vaccines offer the possibility of primary prevention of cervical cancer. The strategy proposed for Mexico includes primary prevention with HPV vaccination for girls aged between 12 and 16 years (before sexual initiation), Pap testing with excellent quality control for women 24-34 years of age and high-risk HPV DNA testing for women 35 years and older. HPV samples would be either clinically collected or self-collected and women with positive HPV test results would receive follow-up high-quality Pap testing. This approach is creative and focuses on reducing disparities and providing high-quality care that is also cost effective.

Frequency and types of human papillomavirus among pregnant and non-pregnant women with human immunodeficiency virus infection in Recife determined by genotyping

Women with human immunodeficiency virus (HIV) infection present a higher risk of infection by the human papillomavirus (HPV) and cervical cancer. To determine HPV genotypes and frequencies among HIV-positive women, an analytical cross-sectional study was carried out on 147 women (51 were pregnant and HIV-positive, 45 pregnant and HIV-negative and 51 HIV-positive and not pregnant), who were attended at a maternity hospital in Recife between April 2006-May 2007. They answered a questionnaire and underwent a gynaecological examination, with samples collected for HPV investigation by PCR, hybrid capture II, oncotic colpocytology (Papanicolau) and colposcopy. The frequency of HPV DNA was 85.3% (122/143), with a high proportion of HPV types that have been identified as high risk for cervical cancer. Among HIV-positive pregnant women, there was an HPV prevalence of 96% (48/50), of whom 60.4% (29/48) were high-risk. HPV 16, 58, 18, 66 and 31 were the most frequent types. Colpocytological abnormalities were observed in 35.3% (18/51) of HIV-positive non-pregnant women, 21.6% (11/51) of HIV-positive pregnant women and 13.3% (6/45) of HIV-negative pregnant women with a predominance of low-level lesions. A high prevalence of HPV infection was identified, especially with the high-risk types 16, 58, 18 and 66. This study identified high-risk HPV types in all three groups examined (HIV-positive pregnant women, HIV-negative pregnant women and HIV-positive not pregnant), characterising its distribution in this setting.

Human papillomavirus in cervical cancer screening: important role as biomarker

Cervical cytology screening has reduced cervical cancer morbidity and mortality but shows important shortcomings in terms of sensitivity and specificity. Infection with distinct types of human papillomavirus (HPV) is the primary etiologic factor in cervical carcinogenesis. This causal relationship has been exploited for the development of molecular technologies for viral detection to overcome limitations linked to cytologic cervical screening. HPV testing has been suggested for primary screening, triage of equivocal Pap smears or low-grade lesions and follow-up after treatment for cervical intraepithelial neoplasia. Determination of HPV genotype, viral load, integration status and RNA expression could further improve the effectiveness of HPV-based screening and triage strategies. The prospect of prophylactic HPV vaccination stresses the importance of modification of the current cytology-based screening approach.

Cost-effectiveness of HPV 16, 18 vaccination in Brazil

We use an empirically calibrated model to estimate the cost-effectiveness of cervical cancer prevention in Brazil, a country with a high cervical cancer burden. Assuming 70% coverage, HPV 16, 18 vaccination of adolescent girls is expected to reduce the lifetime risk of cancer by approximately 42.7% (range, 33.2-53.5%); screening three times per lifetime is expected to reduce risk by 21.9-30.7% depending on the screening test, and a combined approach of vaccination and screening is expected to reduce cancer risk by a mean of 60.8% (range, 52.8-70.1%). In Brazil; provided the cost per vaccinated woman is less than I$ 25, implying a per dose cost of approximately I$ 5, vaccination before age 12, followed by screening three times per lifetime between ages 35 and 45, would be considered very cost-effective using the country's per capita gross domestic product as a cost-effectiveness threshold. Assuming a coverage rate of 70%, this strategy would be expected to prevent approximately 100,000 cases of invasive cervical cancer over a 5-year period. Vaccination strategies identified as cost-effective may be unaffordable in countries with similar socioeconomic profiles as Brazil without assistance; these results can provide guidance to the global community by identifying health investments of highest priority and with the greatest promise.