Reliable high risk HPV DNA testing by polymerase chain reaction: an intermethod and intramethod comparison

Emerging biomarkers and clinical significance of HPV genotyping in prevention and management of cervical cancer

Cervical cancer is a growing and serious problem world-wide in women, but more acute in developing countries especially in Indian subcontinent. The main causative agent for the disease is Human Papilloma Virus (HPV). The history of the cervical cancer goes back to eighteenth century as the HPV infection is reported since 1800s. Presently, the genetic structure of HPV is well defined. Several screening tests including cytology and visual based screening and high risk HPV testing are available. Also available are various clinical and commercial diagnostic tests. However due to the lack of awareness and population-based screening programs, the morbidity and mortality rate is alarmingly high. There are new emerging biomarkers including E6/E7 mRNA, p16^ink4a, markers of aberrant S-phase induction, chromosomal abnormalities and miRNAs along with advanced genotyping methods. These markers have clinical significance and are helpful in disease prevention and management. Further, recent advancement in the field of metagenomics has increased the prospects of identifying newer microbes, viruses hitherto reported thus far in the context of HPV infection. Analysis of HPV cases using modern tools including genotyping using more powerful biomarkers is envisaged to enhance the prospects of early diagnosis, better prognosis, more reliable treatment and eventual management of the disease.

Molecular detection methods of human papillomavirus (HPV)

Human papillomavirus (HPV) testing can identify women at risk of cervical cancer. Currently, molecular detection methods are the gold standard for identification of HPV. The three categories of molecular assays that are available are based on the detection of HPV DNA and include (1) non-amplified hybridization assays, such as Southern transfer hybridization (STH), dot blot hybridization (DB) and in situ hybridization (ISH); (2) signal amplified hybridization assays, such as hybrid capture assays (HC2); (3) target amplification assays, such as polymerase chain reaction (PCR) and in situ PCR. STH requires large amounts of DNA, is laborious and not reproducible, while ISH has only moderate sensitivity for HPV. The sensitivity of the HC2 assay is similar to that of PCR-based assays, with high sensitivity being achieved by signal rather than target amplification. PCR-based detection is both highly sensitive and specific. Since PCR can be performed on very small amounts of DNA, it is ideal for use on specimens with low DNA content. In the future, with the advance of technology, viral DNA extraction and amplification systems will become more rapid, more sensitive, and more automated.

Oncogenic Viruses in Skull Base Chordomas

BACKGROUND

Chordomas are rare tumors assumed to derive from notochordal remnants. We believe that a molecular switch is responsible for their malignant behavior. The involvement of oncogenic viruses has not been studied, however. Thus, in the present study, we investigated the presence of oncogenic viruses in chordomas.

METHODS

DNA and RNA from snap-frozen chordoma (n = 18) and chondrosarcoma (n = 15) specimens were isolated. Real-time PCR or RT-PCR was performed to assess the presence of multiple oncogenic viruses, including herpesviridea (herpes simplex virus [HSV]-1, HSV-2, Epstein-Barr virus [EBV], cytomegalovirus, human herpesvirus [HHV]- 6, HHV-7, and Kaposi's sarcoma-associated herpesvirus), polyomaviridea (parvovirus B19 [PVB19], BK virus, JC virus, Simian virus 40, Merkel cell polyomavirus, human polyomavirus [HPyV]-6, and HPyV-7), papillomaviridae, and respiratory viruses. Immunohistochemistry (IHC) and in situ hybridization (ISH) were used to validate the positive results.

RESULTS

PVB19 DNA was detected in 4 of 18 chordomas (22%) and in 1 of 15 chondrosarcomas (7%). IHC recognizing the VP2 capsid protein of PVB19 showed a positive cytoplasmic staining in 44% of the cases (14 of 32). HHV7 DNA was present in 6 of the 18 chordomas (33%). Genomic DNA of EBV was found in 22% of the samples; however, no positive results were found on ISH. None of the chordoma cases showed any presence of DNA from the remaining viruses.

CONCLUSIONS

Viral involvement in the etiology of chordomas is likely, with PVB19 the most distinguishing.

Management of women with human papillomavirus persistence: long-term follow-up of a randomized clinical trial

BACKGROUND

Introduction of human papillomavirus-based screening is ongoing in many countries, given its higher sensitivity and longer-lasting protection compared with cytology-based screening. However, optimal clinical management of human papillomavirus-positive but cytology-negative women is unclear, and additional studies with clinical follow-up are warranted.

OBJECTIVE

The aim of the current study was to investigate the long-term outcomes of the clinical management used in a double-blind, randomized clinical trial of human papillomavirus screening conducted in the context of the routine, organized screening program in Sweden.

STUDY DESIGN

Among 12,527 women aged 32-38 years enrolled in the trial, we followed up the 195 women who attended the colposcopy screening who were cytologically normal but persistently human papillomavirus positive (at least 12 months later; median, 19 months) in the human papillomavirus testing arm (n = 100) or were randomly selected from the control arm (n = 95). Women in the human papillomavirus testing arm were followed up with repeated human papillomavirus testing, cytologies, and colposcopies if persistently human papillomavirus-positive without cervical intraepithelial neoplasia grade 2 or worse. A similar number of random colposcopies and tests were carried out in the control arm. Women were followed up over 13 years for the main outcome measures: cumulative incidence of cervical intraepithelial neoplasia grade 2 or worse and cervical intraepithelial neoplasia grade 3 or worse.

RESULTS

Among women who continued to attend and had continuous human papillomavirus persistence, all (40 of 40, 100% [95% confidence interval, 91-100%]) developed cervical intraepithelial neoplasia grade 2 or worse. There were no cases among women who cleared their human papillomavirus persistence (0 of 35, 0% (95% confidence interval, 0-10%) (P < .001). Among women who had had human papillomavirus persistence but did not continue with repeated human papillomavirus tests (unknown persistence status), 56% (15 of 27 women) developed cervical intraepithelial neoplasia grade 2 or worse. Almost all cases occurred within 6 years. The intensive clinical management in the trial appeared to result in diagnoses of earlier cervical intraepithelial neoplasia grade 2 or worse but apparently did not prevent cervical intraepithelial neoplasia grade 2 or worse.

CONCLUSION

Women with human papillomavirus persistence will, in general, either become human papillomavirus negative or develop cervical intraepithelial neoplasia grade 2 or worse within 6 years, even with intensive clinical follow-up.

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

HPVs cannot be cultured and the detection of virus relies on a variety of techniques used in immunology, serology, and molecular biology. Currently the only FDA-approved commercially available method for the detection of HPV DNA is the Hybrid Capture assay, version hc2 (Digene, Gaithersburg, MD, USA) which is able to detect 13 high-risk types of HPV. The advantage of PCR-based methods of HPV DNA detection is that they allow for the identification of different types of HPV. This article discusses the advantages and disadvantages of the different methods of HPV DNA detection. HPV DNA testing can be used in a variety of clinical scenarios that include a primary screening test, particularly in women older than 30 years;as an adjunctive test to cytology;to triage women who have an equivocal cytologic finding, e.g., ASC-US, or for follow up post-treatment. In addition, HPV DNA testing can be performed on samples obtained by women themselves (so-called self-sampling), which may be useful in women who are resistant to undergoing gynecologic examinations.

EXPRESSION OF OCT-4, P53, P16 AND KI-67, WITH HPV ASSOCIATED PRECANCER AND CANCER OF THE CERVIX

The pathology of cervical HPV infection is detected by three types of epithelial-mesenchymal spheroidal structures: reparative, neoplastic and cancerous involved in reparation processes and in tumor growth. Cancer spheroids are different from neoplastic not only larger in size but also a tendency to merge, and high expression of p53. Expression of tumor markers p53, p16 and Ki-67 could be used in the early differential diagnosis of precancer and squamous cell carcinoma of the cervix.

HPV Population Profiling in Healthy Men by Next-Generation Deep Sequencing Coupled with HPV-QUEST

Multiple-type human papillomaviruses (HPV) infection presents a greater risk for persistence in asymptomatic individuals and may accelerate cancer development. To extend the scope of HPV types defined by probe-based assays, multiplexing deep sequencing of HPV L1, coupled with an HPV-QUEST genotyping server and a bioinformatic pipeline, was established and applied to survey the diversity of HPV genotypes among a subset of healthy men from the HPV in Men (HIM) Multinational Study. Twenty-one HPV genotypes (12 high-risk and 9 low-risk) were detected in the genital area from 18 asymptomatic individuals. A single HPV type, either HPV16, HPV6b or HPV83, was detected in 7 individuals, while coinfection by 2 to 5 high-risk and/or low-risk genotypes was identified in the other 11 participants. In two individuals studied for over one year, HPV16 persisted, while fluctuations of coinfecting genotypes occurred. HPV L1 regions were generally identical between query and reference sequences, although nonsynonymous and synonymous nucleotide polymorphisms of HPV16, 18, 31, 35h, 59, 70, 73, cand85, 6b, 62, 81, 83, cand89 or JEB2 L1 genotypes, mostly unidentified by linear array, were evident. Deep sequencing coupled with HPV-QUEST provides efficient and unambiguous classification of HPV genotypes in multiple-type HPV infection in host ecosystems.

Expression of P16 in high-risk human papillomavirus related lesions of the uterine cervix in a government hospital, Malaysia

Background

Cervical cancer is one of the most common cancers affecting women worldwide. It is well established that human papilloma virus (HPV) infection is the prime risk factor in the development of cervical cancer. The current screening and diagnostic tests have limitations in identifying the range of lesions caused by HPV. The current study aims to evaluate the diagnostic value of p16 immunohistochemical (IHC) investigation in high-risk human papillomavirus (HR-HPV) related lesions of the uterine cervix in Hospital Tuanku Jaafar, Seremban, Malaysia.

Methods

A total of 75 cases were selected from the records of Pathology services, Hospital Tuanku Ja’afar, Seremban. The samples were collected in three separate groups (n = 25 per group) as Carcinoma cervix, Carcinoma in situ and Chronic cervicitis. The demographic data of the patients and the representative paraffin blocks were retrieved from Hospital Tuanku Ja’afar, Seremban. The immunohistochemical staining with p16 and HPV 16 L1 were done on all cases. The staining intensity and density were observed and compared among the three groups of cases.

Results

Immunohistochemistry of p16INK4A staining shows nil (0/25) expression in the cervicitis patients, 72% (18/25) in CIN patients and 100% (25/25) in cervical carcinoma. HPV 16 L1 was positive in 100% (25/25) of cervicitis patients, 96% (24/25) of CIN patients and 40% (10/25) of cervical cancers patients. A chi square test was used to analyze the result and the obtained p value was <0.05.

Conclusion

p16 expression was strongly observed in cervical cancer and minimally observed in cervicitis. Thus indicating p16 immunohistochemistry investigations can aid in diagnosing the different categories of cervical lesions into benign, insitu and malignant.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_202

Long-term HPV type-specific risks for ASCUS and LSIL: a 14-year follow-up of a randomized primary HPV screening trial

Human papillomavirus (HPV) infections result in a significant burden of low-grade cervical lesions. Between 1997 and 2000, our randomized trial of primary HPV screening enrolled 12,527 women participating in population-based screening. Women between 32 and 38 years of age (median: 34, interquartile range: 33-37) were randomized to HPV and cytology double testing (intervention arm, n = 6,257 enrolled, n = 5,888 followed-up) or to cytology, with samples frozen for future HPV testing (control arm, n = 6,270 enrolled, n = 5,795 followed-up). We estimated the HPV type-specific, long-term absolute risks (AR), and population attributable proportions (PAR) for cytological diagnoses of atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) and for histopathologically diagnosed cervical intraepithelial neoplasia grade 1 (CIN1). The women were followed using comprehensive, nationwide register-based follow-up. During a mean follow-up time of 11.07 years, 886 ASCUS and LSIL lesions were detected, 448 in the intervention arm and 438 in the control arm. Poisson regression estimated the incidence rate ratios (IRRs) of low-grade lesions by HPV type. The IRRs were strongly dependent on follow-up time. The IRRs for ASCUS/LSIL associated with high-risk HPV positivity were 18.6 (95% CI: 14.9-23.4) during the first screening round, 4.1 (95% CI: 2.8-6.2) during the second, 2.6 (95% CI: 1.7-4.1) during the third, and 1.1 (95% CI: 0.7-1.8) for >9 years of follow-up, with similar declines seen for the individual types. Type 16 contributed consistently to the greatest proportion of ASCUS, LSIL, and CIN1 risk in the population (first screening round PAR: ASCUS: 15.5% (95% CI: 9.7-21.9), LSIL: 14.7% (95% CI: 8.0-20.9), and CIN1: 13.4% (95% CI: 3.2-22.5)), followed by type 31 [8.4% (95% CI: 4.2-12.5) for ASCUS to 17.3% (95% CI: 6.8-26.6) for CIN1]. In summary, most ASCUS/LSIL lesions associated with HPV infection are caused by new HPV infections and most lesions are found during the first screening round.

Long term duration of protective effect for HPV negative women: follow-up of primary HPV screening randomised controlled trial

OBJECTIVES

To assess whether the increased sensitivity of screening for human papillomavirus (HPV) may represent overdiagnosis and to compare the long term duration of protective effect against cervical intraepithelial neoplasia grade 2 or worse (CIN2+) in HPV based and cytology based screening.

DESIGN

13 year follow-up of the Swedescreen randomised controlled trial of primary HPV screening.

SETTING

Organised cervical screening programme in Sweden.

PARTICIPANTS

12,527 women aged 32-38 attending organised screening were enrolled and randomised to HPV and cytology double testing (intervention arm, n=6257) or to cytology only, with samples frozen for future HPV testing (control arm, n=6270).

MAIN OUTCOME MEASURES

Cumulative incidence of CIN2+ and CIN3+ (Kaplan Meier curves). Longitudinal test characteristics were calculated for cytology only, HPV testing only, and cytology and HPV testing combined, adjusting for censoring.

RESULTS

The increased detection of CIN2+ in the intervention arm decreased over time. After six years, the cumulative incidence of CIN3+ was similar in both trial arms, and after 11 years the cumulative incidence of CIN2+ became similar in both arms. The longitudinal sensitivity of cytology for CIN2+ in the control arm at three years was similar to the sensitivity of HPV testing in the intervention arm at five years of follow-up: 85.94% (95% confidence interval 76.85% to 91.84%) v 86.40% (79.21% to 91.37%). The sensitivity of HPV screening for CIN3+after five years was 89.34% (80.10% to 94.58%) and for cytology after three years was 92.02% (80.59% to 96.97%).

CONCLUSIONS

Over long term follow-up, the cumulative incidence of CIN2+ was the same for HPV screening and for cytology, implying that the increased sensitivity of HPV screening for CIN2+ reflects earlier detection rather than overdiagnosis. The low long term risks of CIN3+ among women who tested negative in HPV screening, support screening intervals of five years for such women.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00479375.

High-Risk Human Papillomavirus DNA Detected in Primary Squamous Cell Carcinoma of Urinary Bladder

Context.—We reported previously that more than one-third (37%) of primary bladder squamous cell carcinomas (SCCs) demonstrate diffuse p16 immunoreactivity independent of gender. This observation made us question whether p16 overexpression in bladder carcinoma is due to human papillomavirus (HPV)–dependent mechanisms.

Objectives.—To determine whether the presence of high-risk HPV (HR-HPV) DNA could be detected in these tumor cells.

Design.—Fourteen cases of primary bladder SCC, which were positive for p16 by immunohistochemistry, were probed for the detection of HR-HPV by in situ hybridization and the signal amplification Invader assay. Samples positive for detection of HR-HPV by Invader assay were amplified by using HR-HPV type-specific primers, and amplification products were DNA sequenced.

Results.—Detection of HR-HPV by the in situ hybridization method was negative in all cases (0 of 14). However, in 3 of 14 cases (21.4%), the presence of HR-HPV DNA was detected with the Cervista HPV HR Invader assay, which was followed by identification of genotype. All positive cases were confirmed by using HR-HPV type-specific amplification followed by DNA sequencing. Identified HR-HPV genotypes included HPV 16 (2 cases) and HPV 35 (1 case).

Conclusions.—High-risk HPV DNA is detectable in a subset of primary bladder SCCs. Based on the well-documented carcinogenic potential of HR-HPV, there is a necessity for additional studies to investigate the role of HR-HPV in bladder carcinogenesis.

Human papillomavirus detection and typing using a nested-PCR-RFLP assay

BACKGROUND

It is clinically important to detect and type human papillomavirus (HPV) in a sensitive and specific manner.

OBJECTIVES

Development of a nested-polymerase chain reaction-restriction fragment length polymorphism (nested-PCR-RFLP) assay to detect and type HPV based on the analysis of L1 gene.

METHODS

Analysis of published DNA sequence of mucosal HPV types to select sequences of new primers. Design of an original nested-PCR assay using the new primers pair selected and classical MY09/11 primers. HPV detection and typing in cervical samples using the nested-PCR-RFLP assay.

RESULTS

The nested-PCR-RFLP assay detected and typed HPV in cervical samples. Of the total of 128 clinical samples submitted to simple PCR and nested-PCR for detection of HPV, 37 (28.9%) were positive for the virus by both methods and 25 samples were positive only by nested-PCR (67.5% increase in detection rate compared with single PCR). All HPV positive samples were effectively typed by RFLP assay.

CONCLUSION

The method of nested-PCR proved to be an effective diagnostic tool for HPV detection and typing.

High-resolution melting molecular signatures for rapid identification of human papillomavirus genotypes

Background

Genotyping of human papillomarvirus (HPV) is crucial for patient management in a clinical setting. This study accesses the combined use of broad-range real-time PCR and high-resolution melting (HRM) analysis for rapid identification of HPV genotypes.

Methods

Genomic DNA sequences of 8 high-risk genotypes (HPV16/18/39/45/52/56/58/68) were subject to bioinformatic analysis to select for appropriate PCR amplicon. Asymmetric broad-range real-time PCR in the presence of HRM dye and two unlabeled probes specific to HPV16 and 18 was employed to generate HRM molecular signatures for HPV genotyping. The method was validated via assessment of 119 clinical HPV isolates.

Results

A DNA fragment within the L1 region was selected as the PCR amplicon ranging from 215–221 bp for different HPV genotypes. Each genotype displayed a distinct HRM molecular signature with minimal inter-assay variability. According to the HRM molecular signatures, HPV genotypes can be determined with one PCR within 3 h from the time of viral DNA isolation. In the validation assay, a 91% accuracy rate was achieved when the genotypes were in the database. Concomitantly, the HRM molecular signatures for additional 6 low-risk genotypes were established.

Conclusions

This assay provides a novel approach for HPV genotyping in a rapid and cost-effective manner.

Prevalence of human papillomavirus in university young women

Cervical cancer is the second most prevalent female cancer worldwide. The majority of cases appear between the age of 30 and 50. Human papillomavirus (HPV) plays a central role in cervical cancer with 99.7% of HPV DNA identified in invasive cervical carcinomas. The prevalence of the HPV infection varies substantially among countries and according to age and lifestyle. HPV is a common sexually transmitted infection among males and females with a 70% higher incidence in sexually active females. This study aimed to determine the prevalence of human papillomavirus in young university women by analyzing the correlation between Papanicolaou (PAP)-stained cervical tests and HPV detection by genotyping, as well as other risk factors. A total of 200 women aged between 18 and 25 years were enrolled in this study, which took place between September 2008 and May 2009 at the Universidad de Tarapacá, Arica, Chile. Results of the PAP smears showed that 97.5% of cells had normal characteristics, although an inflammatory pattern was noted. The prevalence of generic HPV infection was 3.5% when testing for HPV DNA using the polymerase chain reaction (PCR) method. An analysis of the genotype of infected female individuals indicated that high-risk HPV types, such as HPV 16 and 31 were present in 42.84 and 14.29% of females, respectively, and low-risk types such as HPV 6, in 14.29%. Only one sample with differentiated non-HPV (14.29%) was found. A 95% correlation between PAP-stained cervical tests and the method of testing for HPV was observed. Using the PCR method, it was found that of the 195 negative PAP smears, 5 were positive for HPV and two of the samples that were positive for ASC-US were also positive. A significantly increased (P<0.05) HPV infection risk was observed in the 18-21 age group with a higher prevalence (71.40%) when compared to the 22-25 age group (28.6%). A significant (P<0.042) difference was found between smoking and HPV infection. In conclusion, a significant (P<0.05) correlation was found between PAP and PCR methods for HPV testing in young university women. A significant correlation between smoking and HPV was detected, whereas no difference was noted with other parameters.

Detection and typing of human papilloma virus by multiplex PCR with type-specific primers

The primary underlying cause of cervical cancer is infection with one or more high-risk (HR) types of the human papilloma virus (HPV). Detection and typing of HPV have been commonly carried out by PCR-based assays, where HPV detection and typing are two separate procedures. Here, we present a multiplex PCR-based HPV typing assay that detects 20 HPV types (15 HR, 3 probably HR and 2 low risk) using type-specific primers and agarose gel electrophoresis. 46 cervical, urethral, and biopsy samples were analyzed by both Multiplex PCR and PGMY09/11 consensus PCR, and results were compared. 611 samples were further analyzed by Multiplex PCR, 282 were positive for HR HPV, and 101 showed multiple HR HPV infections. The relatively ease and economic accessibility of the method and its improved ability to detect high-risk HPV types in multiple HPV-infected samples make it an attractive option for HPV testing.

Human papillomavirus genotype detection in recurrent respiratory papillomatosis (RRP) in Colombia

BACKGROUND

Knowledge on human papillomavirus (HPV) genotype distribution in recurrent respiratory papillomatosis (RRP) is essential to assess the impact of HPV vaccine. It is provided information for Colombia.

METHODS

In all, 189 RRP primary cases diagnosed between 1985 and 2009 were identified from 5 pathology laboratories of Cali and Medellin, Colombia. HPV DNA testing in 129 cases that fulfilled inclusion criteria (available paraffin blocks, amplifiable DNA, and confirmed histologic diagnosis of RRP) was performed by the SPF-10/LiPA25 assay (version 1).

RESULTS

Of all cases 36.1% were juvenile (<12 years old) and a majority of adults were males (p = .09); 95% of cases were HPV positive. HPV 6, 11, and 16 contributed to 69%, 27.1%, and 7.8% of all HPV positive cases. Twelve cases (9.3%) showed multiple infections; 8 of these were HPV 6 or 11 positive.

CONCLUSIONS

HPV prophylactic vaccine including HPV 6 and 11 may have a major impact against RRP.

Human papillomavirus infection and esophageal squamous cell carcinoma: a case-control study

BACKGROUND

The risk factors for esophageal squamous cell carcinoma (ESCC) in the high-incidence areas of China remain unclear.

METHODS

A total of 300 patients with ESCC and 900 controls matched for age and sex were enrolled in Anyang (China), a high-risk area for ESCC in China. In tumor tissue of the cases and in esophageal biopsies of controls, the presence of human papillomavirus (HPV) DNA was assessed by an SPF1/GP6(+)-mediated PCR followed by sequencing. The presence of serum antibody against the HPV-16 E7 oncoprotein was assessed by use of the ELISA. ORs with 95% confidence intervals (CI) were calculated via unconditional logistic regression models.

RESULTS

The presence of HPV in the esophagus (OR, 6.4; 95% CI, 4.4-9.2) was associated with increased risk of ESCC. Moreover, infection with "oncogenic" types of HPV (OR, 10.3; 95% CI, 6.3-16.8) was more strongly associated with ESCC than other types of HPV (OR, 2.4; 95% CI, 1.4-4.2). The presence of HPV-16 (OR, 12.8; 95% CI, 7.6-21.7) was particularly strongly associated with ESCC. In addition, a higher proportion of cases than controls had serum antibodies against HPV-16 E7 (OR, 6.1; 95% CI, 3.7-10.0).

CONCLUSION AND IMPACT

This study provides the strongest epidemiologic evidence to date in support of the important role of HPV in the development of ESCC in high-incidence areas of China.

Epidemiologic natural history and clinical management of Human Papillomavirus (HPV) Disease: a critical and systematic review of the literature in the development of an HPV dynamic transmission model

BACKGROUND

Natural history models of human papillomavirus (HPV) infection and disease have been used in a number of policy evaluations of technologies to prevent and screen for HPV disease (e.g., cervical cancer, anogenital warts), sometimes with wide variation in values for epidemiologic and clinical inputs. The objectives of this study are to: (1) Provide an updated critical and systematic review of the evidence base to support epidemiologic and clinical modeling of key HPV disease-related parameters in the context of an HPV multi-type disease transmission model which we have applied within a U.S. population context; (2) Identify areas where additional studies are particularly needed.

METHODS

Consistent with our and other prior HPV natural history models, the literature review was confined to cervical disease and genital warts. Between October 2005 and January 2006, data were gathered from the published English language medical literature through a search of the PubMed database and references were examined from prior HPV natural history models and review papers. Study design and data quality from individual studies were compared and analyses meeting pre-defined criteria were selected.

RESULTS

Published data meeting review eligibility criteria were most plentiful for natural history parameters relating to the progression and regression of cervical intraepithelial neoplasia (CIN) without HPV typing, and data concerning the natural history of HPV disease due to specific HPV types were often lacking. Epidemiologic evidence to support age-dependency in the risk of progression and regression of HPV disease was found to be weak, and an alternative hypothesis concerning the time-dependence of transition rates is explored. No data were found on the duration of immunity following HPV infection. In the area of clinical management, data were observed to be lacking on the proportion of clinically manifest anogenital warts that are treated and the proportion of cervical cancer cases that become symptomatic by stage.

CONCLUSION

Knowledge of the natural history of HPV disease has been considerably enhanced over the past two decades, through the publication of an increasing number of relevant studies. However, considerable opportunity remains for advancing our understanding of HPV natural history and the quality of associated models, particularly with respect to examining HPV age- and type-specific outcomes, and acquired immunity following infection.

ELISA test to detect CDKN2A (p16(INK4a)) expression in exfoliative cells: a new screening tool for cervical cancer

BACKGROUND

The purpose of this study was to use an enzyme-linked immunosorbent assay (ELISA) to detect cyclin-dependent kinase inhibitor 2A (CDKN2A; also known as p16(INK4a)) in exfoliative cervical cells. CDKN2A is upregulated and considered as a surrogate marker for cervical intraepithelial neoplasia and cancer.

METHODS

Liquid-based ThinPrep((R)) cytologic test (TCT) and ELISA were performed on 1356 specimens collected prior to biopsy. A cotton swab was used to gather exfoliative cells. A sandwich ELISA was performed to measure the amount of solublized CDKN2A protein.

RESULTS

The sensitivity and specificity of the TCT for screening of cervical dysplasia and cancer were 82.93% and 88.11%, respectively. The sensitivity and specificity for measuring CDKN2A with ELISA to detect significant cervical disease were 87.80% and 92.43%, respectively. CDKN2A expression was correlated with the severity of cervical damage (r = 0.774; p < 0.001).

CONCLUSION

The sensitivity and specificity of detecting CDKN2A expression with ELISA in exfoliative cervical cells was superior to TCT (p = 0.023 and p < 0.001, respectively). These results suggest that detecting CDKN2A with ELISA has the potential to become a new screening method for cervical cancer.

Guidelines for human papillomavirus DNA test requirements for primary cervical cancer screening in women 30 years and older

Given the strong etiologic link between high-risk HPV infection and cervical cancer high-risk HPV testing is now being considered as an alternative for cytology-based cervical cancer screening. Many test systems have been developed that can detect the broad spectrum of hrHPV types in one assay. However, for screening purposes the detection of high-risk HPV is not inherently useful unless it is informative for the presence of high-grade cervical intraepithelial neoplasia (CIN 2/3) or cancer. Candidate high-risk HPV tests to be used for screening should reach an optimal balance between clinical sensitivity and specificity for detection of high-grade CIN and cervical cancer to minimize redundant or excessive follow-up procedures for high-risk HPV positive women without cervical lesions. Data from various large screening studies have shown that high-risk HPV testing by hybrid capture 2 and GP5+/6+-PCR yields considerably better results in the detection of CIN 2/3 than cytology. The data from these studies can be used to guide the translation of high-risk HPV testing into clinical practice by setting standards of test performance and characteristics. On the basis of these data we have developed guidelines for high-risk HPV test requirements for primary cervical screening and validation guidelines for candidate HPV assays.

Overview of human papillomavirus-based and other novel options for cervical cancer screening in developed and developing countries

Screening for cervical cancer precursors by cytology has been very successful in countries where adequate resources exist to ensure high quality and good coverage of the population at risk. Mortality reductions in excess of 50% have been achieved in many developed countries; however the procedure is generally inefficient and unworkable in many parts of the world where the appropriate infrastructure is not achievable. A summary and update of recently published meta-analyses and systematic reviews on four possible clinical applications of human papillomavirus (HPV) DNA testing is provided in this article: (1) triage of women with equivocal or low-grade cytological abnormalities; (2) follow-up of women with abnormal screening results who are negative at colposcopy/biopsy; (3) prediction of the therapeutic outcome after treatment of cervical intraepithelial neoplasia (CIN), and most importantly (4) primary screening HPV DNA test, solely or in combination with Pap smear to detect cervical cancer precursors. There are clear benefits for the use of HPV DNA testing in the triage of equivocal smears, low-grade smears in older women and in the post-treatment surveillance of women after treatment for CIN. However, there are still issues regarding how best to use HPV DNA testing in primary screening. Primary screening with Hybrid Capture((R)) 2 (HC2) generally detects more than 90% of all CIN2, CIN3 or cancer cases, and is 25% (95% CI): 15-36%) relatively more sensitive than cytology at a cut-off of abnormal squamous cells of undetermined significance (ASC-US) (or low-grade squamous intraepithelial lesions (LSIL) if ASC-US unavailable), but is 6% (95% CI: 4-7%) relatively less specific. Several approaches are currently under evaluation to deal with the lower specificity of HPV DNA testing as associated with transient infection. These include HPV typing for HPV-16 and -18/45, markers of proliferative lesions such as p16 and mRNA coding for the viral E6 and/or E7 proteins, with a potential clinical use recommending more aggressive management in those who are positive. In countries where cytology is of good quality, the most attractive option for primary screening is to use HPV DNA testing as the sole screening modality with cytology reserved for triage of HPV-positive women. Established cytology-based programmes should also be gradually moving towards a greater use of HPV DNA testing to improve their efficacy and safely lengthen the screening interval. The greater sensitivity of HPV DNA testing compared to cytology argues strongly for using HPV DNA testing as the primary screening test in newly implemented programmes, except where resources are extremely limited and only programmes based on visual inspection are affordable. In such countries, use of a simple HPV DNA test followed by immediate 'screen and treat' algorithms based on visual inspection in those who are HPV-positive are needed to minimise the number of visits and make best use of limited resources. A review of studies for visual inspection methods is presented. The fact that HPV is a sexually transmitted infection may lead to anxiety and concerns about sexual relationships. These psychosocial aspects and the need for more information and educational programmes about HPV are also discussed in this article.

Immunocytochemical staining of p16(ink4a) protein as an adjunct test in equivocal liquid-based cytology

For cervical cancer screening, HPV-DNA test is expensive and is not easily available in all clinical situations. Thus, we investigated the role of p16(ink4a) immunostaining as another adjunct test to diagnose cervical neoplasia in equivocal liquid based cytology. Eighty-seven patients were randomly selected for this study (3 patients with normal, 84 patients with abnormal including 24 ASCUS, 30 LSIL, and 30 HSIL). We performed p16(ink4a) immunostaining on ThinPrep slide and on each case from the corresponding cervical biopsy tissues. High-risk HPV-DNA testing was also performed on all the subjects. We found that the immunoreactivity of p16(ink4a) is strongly correlated with the grade of cytologic and histologic diagnoses as well as with Hybrid Capture 2. In comparing the p16(ink4a) immunostaining with the Hybrid Capture 2 for accuracy of the diagnosis of CIN II/III or a higher-grade disease in the case of ASCUS/LSIL on ThinPrep, no significant differences were observed. Our data implies that p16(ink4a) immunocytochemical staining in liquid-based cytology specimens might be used as a good adjunct test to predict cervical histology in equivocal ThinPrep tests.

Human papillomavirus DNA testing for the detection of cervical intraepithelial neoplasia grade 3 and cancer: 5-year follow-up of a randomised controlled implementation trial

BACKGROUND

Tests for the DNA of high-risk types of human papillomavirus (HPV) have a higher sensitivity for cervical intraepithelial neoplasia grade 3 or worse (CIN3+) than does cytological testing, but the necessity of such testing in cervical screening has been debated. Our aim was to determine whether the effectiveness of cervical screening improves when HPV DNA testing is implemented.

METHODS

Women aged 29-56 years who were participating in the regular cervical screening programme in the Netherlands were randomly assigned to combined cytological and HPV DNA testing or to conventional cytological testing only. After 5 years, combined cytological and HPV DNA testing were done in both groups. The primary outcome measure was the number of CIN3+ lesions detected. Analyses were done by intention to treat. This trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN20781131.

FINDINGS

8575 women in the intervention group and 8580 in the control group were recruited, followed up for sufficient time (> or =6.5 years), and met eligibility criteria for our analyses. More CIN3+ lesions were detected at baseline in the intervention group than in the control group (68/8575 vs 40/8580, 70% increase, 95% CI 15-151; p=0.007). The number of CIN3+ lesions detected in the subsequent round was lower in the intervention group than in the control group (24/8413 vs 54/8456, 55% decrease, 95% CI 28-72; p=0.001). The number of CIN3+ lesions over the two rounds did not differ between groups.

INTERPRETATION

The implementation of HPV DNA testing in cervical screening leads to earlier detection of CIN3+ lesions. Earlier detection of such lesions could permit an extension of the screening interval.

Emerging biomarkers in the detection, diagnosis and management of cervical dysplasia and carcinoma

Despite the success of widespread screening, cervical cancers continue to occur. Recently, the role of human papillomavirus (HPV) in cervical carcinogenesis has been firmly established. HPV prophylactic vaccines are expected to eradicate ∼ 70% of cervical cancers. An HPV test was demonstrated to improve the sensitivity of cytology and prolong the screening interval safely. Type-specific HPV testing will play an important role in the detection and follow up of cervical neoplastic lesions, as well as monitoring the efficacy of HPV vaccines. The combined use of cell proliferation markers with cytology can improve sensitivity, and some molecular markers seem to be related to the degree of dysplasia. Further studies are needed to evaluate the use of biomarkers in clinical settings.

Population-based study of screening test performance indices of three human papillomavirus DNA tests

In order to evaluate three common human papillomavirus (HPV) DNA tests for key performance indices in population-based cervical screening, we sampled 12,527 women aged 32-38 years who attended invitational, population-based screening and followed them for 4 years with comprehensive registry linkages. Three different HPV DNA tests (GP5+/6+ general primer PCR (using either AmpliTaq or AmpliTaq Gold DNA polymerase), Amplicor PCR and Hybrid Capture II were evaluated using baseline samples from women who on follow-up developed cervical intraepithelial neoplasia grade 2 or worse (CINII+) (n = 197) as well as a representative subsample of the women in the cohort (n = 794). The population-based HPV prevalence, sensitivity for future cervical intraepithelial neoplasia grade 2 or worse (CINII+), and absolute risk of CINII+ was 7.1%, 87.1%, and 23.2% for AmpliTaq GP5+/6+ PCR, 11.9%, 88.9%, and 11.0% for AmpliTaq Gold GP5+/6+ PCR, 15.7%, 93.4%, and 9.8% for Amplicor, 10.0%, 92.9%, and 15.3% for Amplicor with raised cut-off, and 7.8%, 79.7%, and 16.9% for Hybrid Capture II. In conclusion, AmpliTaq GP5+/6+ PCR and Amplicor with raised cut-off value have adequate performance indices for primary screening.

Inter-laboratory validation of PCR-based HPV detection in pathology specimens

The detection and typing of human papilloma virus (HPV) in pathology specimens is gaining increasingly in importance. In the context of the initiative for quality assurance in pathology (QuIP) of the German Society of Pathology and the Professional Association of German Pathologists, four panel laboratories with experience and expertise in polymerase chain reaction (PCR)-based HPV detection were selected to establish an inter-laboratory trial. In a first step, these laboratories performed an internal testing of their own methodologies, which comprised DNA sequencing, multiplex nested PCR and hybridization techniques. Material from 39 samples including paraffin sections and DNA preparations of tissues and plasmids were evaluated by each panel institute according to their own protocols. Despite the different methodologies, a high degree of inter-laboratory reliability was achieved. In this report, we summarise the results. Pretested specimens are available for the external trail and can be ordered from the steering institute via provitro GmbH Berlin ( http://www.provitro.de ). Supplementary data are online available at http://pathologie-ccm.charite.de (rubric "Forschung"), which includes a web-based photo gallery of HPV-associated lesions and their potential association with specific virus types. The initiative is intended to foster the quality assurance of molecular HPV analysis in pathology and its correlation with morphological changes.

Cross-sectional comparison of an automated hybrid capture 2 assay and the consensus GP5+/6+ PCR method in a population-based cervical screening program

In this cross-sectional study, clinical performances of the hybrid capture 2 assay using an automated instrument (i.e., rapid capture system) (hc2-RCS) and the high-risk human papillomavirus GP5+/6+ PCR-enzyme immunoassay (EIA) test were compared using cervical scrape specimens from 8,132 women that participated in a population-based screening trial. The hc2-RCS test scored significantly more samples positive (6.8%) than the GP5+/6+ PCR-EIA (4.8%) (P < 0.0005). This could be attributed largely to a higher positivity rate by the hc2-RCS test for women with cytologically normal, borderline, or mild dyskaryosis. A receiver operator characteristics analysis of the semiquantitative hc2-RCS results in relation to different cytology categories revealed that these differences are owing to differences in assay thresholds. For women classified as having moderate dyskaryosis or worse who also had underlying histologically confirmed cervical intraepithelial neoplasia grade 3 or cervical cancer (> or =CIN3), the hc2-RCS scored 97% (31/32) of samples positive, versus 91% (29/32) by GP5+/6+ PCR-EIA. However, this difference was not significant (P = 0.25). After increasing the hc2-RCS cutoff from 1.0 to 2.0 relative light units/cutoff value of the HPV16 calibrator (RLU/CO), no additional CIN3 lesions were missed by hc2-RCS, but the number of test-positive women with normal, borderline, or mild dyskaryosis was significantly decreased (P < 0.0005). However, at this RLU/CO, the difference in test positivity between hc2-RCS and the GP5+/6+ PCR-EIA was still significant (P = 0.02). The use of an RLU/CO value of 3.0 revealed no significant difference between hc2-RCS and GP5+/6+ PCR-EIA results, and equal numbers of smears classified as > or =CIN3 (i.e., 29/32) were detected by both methods. In summary, both assays perform very well for the detection of >or =CIN3 in a population-based cervical screening setting. However, adjustment of the hc2-RCS threshold to an RLU/CO value of 2.0 or 3.0 seems to produce an improved balance between the clinical sensitivity and specificity for > or =CIN3 in population-based cervical screening.

Reproductive Factors, Oral Contraceptive Use, and Human Papillomavirus Infection: Pooled Analysis of the IARC HPV Prevalence Surveys

High parity, early age at first full-term pregnancy (FTP), and long-term oral contraceptive (OC) use increase cervical cancer risk, but it is unclear whether these variables are also associated with increased risk of acquisition and persistence of human papillomavirus (HPV) infection, the main cause of cervical cancer. Information on reproductive and menstrual characteristics and OC use were collected from 14 areas worldwide, among population-based, age-stratified random samples of women aged 15 years or older. HPV testing was done using PCR-based enzyme immunoassay. Unconditional logistic regression was used to estimate the odds ratios (OR) of being HPV-positive according to reproductive and menstrual factors and corresponding 95% confidence intervals (CI). When more than two groups were compared, floating CIs (FCI) were estimated. A total of 15,145 women (mean age, 40.9 years) were analyzed. Women with >or=5 FTPs (OR, 0.90; 95% FCI, 0.76-1.06) showed a similar risk of being HPV-positive compared with women with only one FTP (OR, 1.00; 95% FCI, 0.86-1.16). However, nulliparous women showed an OR of 1.40 (95% CI, 1.16-1.69) compared with parous women. Early age at first FTP was not significantly related to HPV positivity. HPV positivity was similar for women who reported >or=10 years of use of OCs (OR, 1.16; 95% FCI, 0.85-1.58) and never users of OCs (OR, 1.00; 95% FCI, 0.90-1.12). Our study suggests, therefore, that high parity, early age at first FTP, and long-term OC use are not associated with HPV prevalence, but rather these factors might be involved in the transition from HPV infection to neoplastic cervical lesions.

Chapter 3: HPV type-distribution in women with and without cervical neoplastic diseases

Geographical widespread data on human papillomavirus (HPV) type-distribution are essential for estimating the impact of HPV-16/18 vaccines on cervical cancer and cervical screening programmes. Epidemiological studies employing a variety of HPV typing protocols have been collated in meta-analyses. HPV-16/18 is estimated to account for 70% of all cervical cancers worldwide, although the estimated HPV-16/18 fraction is slightly higher in more developed (72-77%) than in less developed (65-72%) regions. About 41-67% of high-grade squamous intraepithelial lesion (HSIL), 16-32% of low-grade squamous intraepithelial lesion (LSIL) and 6-27% of atypical squamous cells of undetermined significance (ASCUS) are also estimated to be HPV-16/18-positive, thus highlighting the increasing relative frequency of HPV-16/18 with increasing lesion severity. After HPV-16/18, the six most common HPV types are the same in all world regions, namely 31, 33, 35, 45, 52 and 58; these account for an additional 20% of cervical cancers worldwide.

Colposcopic and histopathologic evaluation of women participating in population-based screening for human papillomavirus deoxyribonucleic acid persistence

OBJECTIVE

Evaluation of colposcopic and histopathological findings in women screened for cervical human papillomavirus deoxyribonucleic acid persistence.

STUDY DESIGN

A total of 12 527 women, aged 32 to 38 years old, attending the population-based cervical cancer screening program in Sweden were randomized 1:1 to mock testing or human papillomavirus deoxyribonucleic acid testing by general primer 5+/6+ polymerase chain reaction and subsequent typing. Human papillomavirus deoxyribonucleic acid-positive women with a normal Papanicolaou smear (n=341) and an equal number from the control group were human papillomavirus tested on average 19 months later. One hundred nineteen women with type-specific human papillomavirus persistence and 111 controls were referred to colposcopy, and 84.8% attended.

RESULTS

Histopathology from colposcopically directed biopsies confirmed cervical intraepithelial neoplasia grade 2 or 3 in 28 of 100 of the women with human papillomavirus deoxyribonucleic acid persistence and in 2 of 95 among controls.

CONCLUSION

Among women with normal Papanicolaou smear attending population-based screening, the positive predictive value of human papillomavirus deoxyribonucleic acid persistence for detection of biopsy-confirmed cervical intraepithelial neoplasia 2 or 3 was 29%.

Immunocytochemical staining of p16INK4a protein from conventional Pap test and its association with human papillomavirus infection

The p16INK4a protein is immunocytochemically detected in liquid-based (LB) specimens as a diagnostic marker of cervical dysplasia and neoplasia. Its up-regulation is promoted by high-risk human papillomavirus (HR-HPV) infection. We aimed to detect p16INK4a on conventional Papanicolaou (Pap) test (CPT) slides and to determine the relationship between its overexpression and HR-HPV infection. CPT and LB Pap test (LBPT) slides (165 samples of each) were examined by immunocytochemical staining for p16INK4a. After polymerase chain reaction (PCR), HPV-DNA was genotyped by dot blot hybridization. The CPT slides displayed more numerous dispersed squamous cells and LBPT slides had a clearer background. Positive p16INK4a on CPT occurred in 0% (0/30), 52.5% (21/40), 54.3% (19/35), 100% (30/30), and 100% (30/30) in normal, atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesions (LSILs), high-grade SILs (HSILs), and squamous cell carcinomas (SCCs) cases, respectively. LBPT slides showed comparable results but were less sensitive. HPV-DNA was detected in 86.7, 70, 45, 57.14, and 10% in SCCs, HSILs, ASCUS, LSILs, and normal cervical cells, respectively. Because HR-HPV was identified in all HPV+ samples of high-grade dysplasia (HSILs and SCCs) and all positive p16INK4a samples infected with HR-HPV, the association of p16INK4a overexpression with HR-HPV infection was confirmed. This study suggests that immunocytochemical staining of p16INK4a on CPT slides is convenient and cost-effective for cervical cancer screening by the detection of dysplastic cells infected with HR-HPV.

Factors predicting successful DNA recovery from archival cervical smear samples

Polymerase chain reaction (PCR)-based DNA testing of archival cervical smear slides is a useful method of retrospectively establishing the presence of the human papillomavirus (HPV) in cervical cells. A cellular DNA recovery test is performed in parallel to HPV DNA testing to ensure that sufficient cells are present and purification of sample DNA has been successfully performed. Previous studies have not comprehensively assessed DNA recovery rates in slides older than 13 years. We undertook a study to determine the factors impacting DNA recovery in 436 UK slides dating from 11 to 33 years prior to testing. Overall, a low cellular DNA recovery success rate of 29% was obtained but a strong trend was observed with increasing recovery rates the older the slides (P < 0.001). Recovery rates increased from 22% in the most recent slides collected from 1988 to 1992, to 61% in the oldest slides, collected in 1970-72. It is likely that fixation compounds incorporating acetic acid, introduced in the UK through the 1980s, have compromised subsequent attempts at PCR amplification. These findings emphasize the importance of the original fixation method in the success of DNA recovery from archival smear samples.

Chromosome in situ hybridisation, Ki-67, and telomerase immunocytochemistry in liquid based cervical cytology

AIMS

To assess the potential value of chromosome in situ hybridisation (CISH), Ki-67, and telomerase immunocytochemistry in liquid based cervical cytology to help detect carcinoma cells and precursors.

METHOD

Sixty ThinPrep processed cervical cytology samples were studied: 23 cases within the normal limit, 13 low grade squamous intraepithelial lesions (LSILs), 10 high grade squamous intraepithelial lesions (HSILs), six squamous cell carcinomas, three endocervical adenocarcinomas, two cervical adenosquamous cell carcinomas, and three endometrial adenocarcinomas. CISH was performed with DNA probes specific for the pericentromeric regions of chromosome 11 and 16. Hybridisation signals were visualised with the streptavidin-biotin peroxidase technique. The monoclonal MIB1 and polyclonal TRT-H231 antibodies were used to detect Ki-67 and telomerase immunoreactivity, respectively.

RESULTS

Non-specific background staining was almost absent in CISH slides. Normal squamous and glandular cells showed a diploid chromosomal pattern. A relative gain in chromosomes 11 and 16 (aneusomy) was seen in HSIL and the carcinomas (p<0.0001). In MIB1 stained smears, normal cells and koilocytes showed inconspicuous immunoreactivity, whereas strongly immunoreactive nuclei were found in cancer cells and HSIL (p<0.0001). Not only carcinoma and HSIL cells, but also some normal cells, showed cytoplasmic staining for telomerase.

CONCLUSIONS

These preliminary results indicate that ThinPrep processed cervical smears are suitable for CISH and immunocytochemical studies. The neoplastic squamous and glandular cells were easily identified based on nuclear aneusomy and strong Ki-67 immuoreactivity in the context of abnormal nuclear morphology. This is the first study to apply CISH in cervical cytology using an immunoenzymatic approach.

Restriction fragment length polymorphism of L1 amplicon using Rsa 1 detects five different human papillomavirus types and their co-infections among women attending a gynaecological outpatient department

Detection of human papillomavirus (HPV) types 6, 11, 16, 18, and 33 including co-infections among females attending gynaecological outpatient department and cancer clinics, was done by restriction fragment length polymorphism (using Rsa-1), of approximately 450bp amplicon, obtained by the amplification of the L1 region of HPV genome with consensus primers MY09/11 [Cancer Cells 7 (1989) 209]. The results were further tested with HPV type specific primers [J. Med. Virol. 29 (1989) 20]. The technique was found to be low-cost and less time consuming. The advantage of Rsa 1 over other enzymes was that it detects the five most prevalent HPV types commonly associated with warts, cervical dysplasia, and cancer.

Usefulness of liquid-based cytology specimens for the immunocytochemical study of p16 expression and human papillomavirus testing

BACKGROUND

In cervical lesions, the overexpression of p16 is reported to be closely associated with high-risk human papillomavirus (HPV) infection. The objective of the current study was to confirm the usefulness of liquid-based cervical specimens for p16 staining as well as tissue sections.

METHODS

A total of 98 patients with cervical lesions were entered into the current study. After the cytologic examination using liquid-based cervical smears, the same slides were immunostained for p16 and were compared with slides of simultaneously obtained, immunohistologically stained tissue sections. Moreover, the status of the HPV infection was examined by polymerase chain reaction using residual cytologic samples.

RESULTS

Using liquid-based Pap smears, 98 cases were diagnosed as atypical squamous cells of undetermined significance (38 cases), low-grade squamous intraepithelial lesion (12 cases), high-grade squamous intraepithelial lesion (HSIL) (33 cases), and invasive carcinoma (15 cases). The concordance rate between the cytologic and histologic diagnoses was found to be higher in high-grade lesions compared with low-grade lesions. Immunohistochemistry revealed that all HSIL and invasive carcinoma cases contained p16-positive cells in the liquid-based Pap smears and diffuse p16 staining was observed in all high-grade lesions with greater than CIN Grade 3 cervical intraepithelial neoplasia except for two adenocarcinoma cases. Of the 98 cases, 60 were found to be positive for high-risk HPV and 55 of these 60 HPV-positive cases were found to be p16 positive on cytologic examination. There were 16 cases that demonstrated marked discrepancies between the cytologic and histologic diagnoses.

CONCLUSIONS

The results of the current study confirmed that the immunohistochemical detection of p16 was more sensitive and specific than HPV status in cervical lesions using a liquid-based method as well as tissue samples, suggesting that p16 should be used as a satisfactory biomarker for the primary screening of cervical cytology.

Human papillomavirus (HPV) study of 2916 cytological samples by PCR and DNA sequencing: genotype spectrum of patients from the west German area

Human papillomaviruses (HPVs) are aetiological agents for cervical cancer. More than 70 different HPV types that infect genital mucosa have been found. In order to develop a sensitive and specific detection and typing assay, a PCR/direct sequencing approach was used. Two pairs of consensus primers were used for amplification of HPV DNA and the PCR products obtained were analysed by automated sequencing. Sequences were compared with those in GenBank by using the blast program. In this study, 2916 cytological samples were screened for HPV, as well as for triage. Nine hundred and forty-eight (32.5 %) samples were positive for HPV, of which 134 harboured more than one HPV type. Of the 948 PCR-positive samples, 648 were typed. Thirty-nine different HPV types were identified by sequencing. The two most frequently found HPV types, 16 and 31, together accounted for 36.3 % of the sequences (26.2 and 10.1 %, respectively). This group was followed by HPV types 6 (5.7 %), 18 (5.3 %), 58 (4.5 %), 61 (4.5 %), 53 (4.4 %), 42 (4.3 %) and 51 (4.0 %). All other types were detected at frequencies <4 % and eight types were detected only once. PCR/direct sequencing is a reliable method for routine detection of HPV in cytological samples. The data presented here suggest a complex distribution of HPV types in the population tested. The results accentuate the importance of PCR-based techniques in HPV diagnosis, as hybridization-based methods can only detect a limited number of infections. This method can also be applied easily to the analysis of tissue samples and it therefore also allows type-specific follow-up of women who have been treated for cervical intraepithelial neoplasia.

Chapter 12: Human papillomavirus technologies

Currently, human papillomavirus (HPV) DNA tests validated in large trials and epidemiological studies are the hybrid capture second-generation (HC2) HPV DNA assay and a variety of polymerase chain reaction (PCR) protocols employing degenerate or consensus primers. This article describes the currently available technology for HPV detection and discusses novel technologies and their potential for large-scale screening. Ideally, an HPV test should allow detection of multiple HPV types, identify individual types, and provide quantitative information about the viral load of each individual type found. Moreover, it should be easy to perform, be highly reproducible, with a high specificity and sensitivity, and amenable for high throughput analysis and automation. Because we do not yet fully understand the true value of viral load and the biological relevance of the different HPV types, any HPV test should be able to detect the clinically relevant high-risk types with a sufficient sensitivity of at least 10 000 genome copies per sample. To validate the different current and future test systems and to compare inter-laboratory performance we urgently need reference samples, validated reagents, and standardized protocols.

Human papillomavirus testing methods

Testing for human papillomavirus (HPV) relies exclusively on techniques of molecular biology using nucleic acid probes. Tests for HPV using nucleic acid probes have been commercially available since the late 1980s, but early tests were cumbersome, involving the use of nucleic acid probes labeled with radioactive phosphorus (32P). These early HPV tests did not achieve widespread use because they did not detect all oncogenic HPV genotypes. The current commercial HPV detection kit, Digene's Hybrid Capture 2 kit, detects virtually all high-risk oncogenic HPV types, as well as most low-risk nononcogenic HPV genotypes. The Hybrid Capture 2 test format is a proprietary nucleic acid hybridization signal amplification system owned by Digene Corporation. Virtually all test formats for DNA sequence analysis are amenable to applications intended to detect and perhaps quantify the various HPV genotypes. These methods can involve direct hybridization with complementary DNA probes, such as Southern blotting or in situ hybridization, signal amplification, such as the Hybrid Capture 2 method or target nucleic acid amplification, most notably the polymerase chain reaction (PCR). Polymerase chain reaction has been used for HPV detection, genotyping, and viral load determination. General or consensus primer-mediated PCR assays have enabled screening for a broad spectrum of HPV types in clinical specimens using a single PCR reaction. Following amplification using consensus primers, individual HPV genotypes are identified using a variety of methods. Using consensus primers in a test format known as real-time quantitative PCR (RQ-PCR), it is possible to generate viral load (concentration) data from reaction curves generated by monitoring PCR reaction kinetics in real time.

Type-specific detection of human papillomaviruses in a routine laboratory setting--improved sensitivity and specificity of PCR and sequence analysis compared to direct hybridisation

Human papillomaviruses (HPV) are known to cause cervical dysplasia and cervical carcinoma. We used a 3-step PCR protocol that allows rapid type-specific HPV testing in a routine laboratory setting: HPV-16-positive samples were determined using a specific LightCycler PCR; HPV-16-negative samples were amplified by nested PCR and typed by sequence analysis. During a period of 7 months, 1275 PCR-based HPV tests were performed. Of the 1275 samples, 829 samples tested negative for HPV and 446 tested positive, including 124 positives found in the initial HPV-16-specific LightCycler assay. Sequence analysis of 132 samples detected 18 HPV types that are not included in the widely used Hybrid Capture II assay. For comparison, the first 100 cervical specimens were tested in parallel using PCR and direct hybridisation (Hybrid Capture II assay). PCR detected HPV DNA in 23 samples that tested negative in the Hybrid Capture assay. Four out of 37 samples that tested positive for HPV in the Hybrid Capture test may be false positives, because sequence analysis detected HPV types not included in the probe mixtures. As rare and novel HPV types may also confer an oncogenic risk, highly sensitive and specific PCR assays will help in understanding cervical HPV infection and cervical cancer of unknown causes.

International proficiency study of a consensus L1 PCR assay for the detection and typing of human papillomavirus DNA: evaluation of accuracy and intralaboratory and interlaboratory agreement

The PGMY L1 consensus primer pair combined with the line blot assay allows the detection of 27 genital human papillomavirus (HPV) genotypes. We conducted an intralaboratory and interlaboratory agreement study to assess the accuracy and reproducibility of PCR for HPV DNA detection and typing using the PGMY primers and typing amplicons with the line blot (PGMY-LB) assay. A test panel of 109 samples consisting of 29 HPV-negative (10 buffer controls and 19 genital samples) and 80 HPV-positive samples (60 genital samples and 20 controls with small or large amounts of HPV DNA plasmids) were tested blindly in triplicate by three laboratories. Intralaboratory agreement ranged from 86 to 98% for HPV DNA detection. PGMY-LB assay results for samples with a low copy number of HPV DNA were less reproducible. The rate of intralaboratory agreement excluding negative results for HPV typing ranged from 78 to 96%. Interlaboratory reliability for HPV DNA positivity and HPV typing was very good, with levels of agreement of >95% and kappa values of >0.87. Again, low-copy-number samples were more prone to generating discrepant results. The accuracy varied from 91 to 100% for HPV DNA positivity and from 90 to 100% for HPV typing. HPV testing can thus be accomplished reliably with PCR by using a standardized written protocol and quality-controlled reagents. The use of validated HPV DNA detection and typing assays demonstrating excellent interlaboratory agreement will allow investigators to better compare results between epidemiological studies.

Human papillomavirus DNA in cervical lesions from Morocco and its implications for cancer control

To determine the types of human papillomaviruses (HPV) in northern Morocco, information which is needed for the design and use of HPV vaccines, we have analysed 129 cervical biopsies from this region. In our study, 91 cases were HPV positive, 45 cases had HPV-16 DNA, and 20 cases had HPV-18 DNA. This distribution of virus type was similar in inflammatory cervical lesions and in invasive cervical carcinomas. In conclusion, the HPV type distribution in Morocco is similar to that in other African Mediterranean countries, where the proportion of HPV-18 cases is significantly higher than in Europe. Determination of virus-type distribution is essential for vaccination programs.

HLA class II polymorphisms and susceptibility to recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is characterised by multiple laryngeal papillomas. Left untreated, the lesions enlarge, spread, and endanger the airway. Medical treatments are unsatisfactory, and repeated surgery remains the mainstay of therapy. RRP is caused by human papillomavirus (HPV) infection. However, since oral HPV infection is common and RRP is rare, other host and/or viral factors may contribute to pathogenesis. In an attempt to identify such factors, we have investigated 60 patients. The patients were HLA class I, II, and tumor necrosis factor TNF typed by sequence-specific primer PCR, and the results compared to those for 554 healthy controls by using Fisher's exact test. Peripheral blood mononuclear cell proliferative responses of 25 controls and 10 patients to HPV-11 L1 virus-like particles (VLP) were compared. Short-term VLP-specific T-cell lines were established, and recognition of L1 was analyzed. Finally, the L1 open reading frames of HPV isolates from four patients were sequenced. Susceptibility to RRP was associated with HLA DRB1*0301 (33 of 60 patients versus 136 of 554 controls, P < 0.0001). The three most severely affected patients were homozygous for this allele. A range of T-cell proliferative responses to HPV-11 VLP were observed in DRB1*0301-positive healthy donors which were comparable to those in DRB1*0301-negative controls. Individuals with juvenile-onset RRP also mounted a range of VLP responses, and their magnitude was negatively correlated with the clinical staging score (P = 0.012 by the Spearman rank correlation). DRB1*0301-positive patients who responded to L1 recognized the same epitope as did matched controls and produced similar cytokines. Sequencing of clinical isolates excluded the possibility that nonresponsiveness was the result of mutation(s) in L1.

p16INK4A as a marker for cervical dyskaryosis: CIN and cGIN in cervical biopsies and ThinPrep smears

AIM

To examine the potential of p16(INK4A) as a biomarker for dysplastic squamous and glandular cells of the cervix in tissue sections and ThinPrep smears.

METHODS

Immunocytochemical analysis of p16(INK4A) expression was performed on 22 normal cervical tissue samples, five cervical glandular intraepithelial neoplasia (cGIN), 38 cervical intraepithelial neoplasia 1 (CIN1), 33 CIN2, 46 CIN3, and 10 invasive cancer cases (eight squamous and two adenocarcinomas). All samples were formalin fixed and paraffin wax embedded, and immunohistochemical analysis was carried out using a mouse monoclonal anti-p16(INK4A) antibody after antigen unmasking. The staining intensity was assessed using a 0 to 3 scoring system. In addition, the expression status of p16(INK4A) was examined in 12 normal ThinPrep smears, one smear exhibiting cGIN, and a total of 20 smears exhibiting mild, moderate, and severe dyskaryosis. Human papillomavirus (HPV) detection was carried out using a modified SYBR green assay system. Fluorogenic polymerase chain reaction (PCR) and solution phase PCR were used for specific HPV typing.

RESULTS

p16(INK4A) immunoreactivity was absent in all normal cervical tissues examined. Dysplastic squamous and glandular cells were positive for p16(INK4A) expression in all cases included in this study, except for one CIN3 case. p16(INK4A) expression was mainly nuclear in CIN1 cases, and both nuclear and cytoplasmic in CIN2, CIN3, cGIN, and invasive cases. All cases positive for HPV expressed the p16(INK4A) protein, although not all cases found positive for p16(INK4A) were HPV positive. In general, the p16(INK4A) staining intensity was lower in cases negative for HPV or those containing a low risk HPV type.

CONCLUSION

This pattern of overexpression demonstrates the potential use of p16(INK4A) as a diagnostic marker for cervical squamous and also glandular neoplastic lesions. In addition, the technique can be used to identify individual dyskaryotic cells in ThinPrep smears. Thus, p16(INK4A) is a useful marker of cervical dyskaryosis.