Human papillomavirus findings in relation to cervical intraepithelial neoplasia grade: a study on 476 Stockholm women, using PCR for detection and typing of HPV

Superinfection Exclusion between Two High-Risk Human Papillomavirus Types during a Coinfection

Superinfection exclusion is a common phenomenon whereby a single cell is unable to be infected by two types of the same pathogen. Superinfection exclusion has been described for various viruses, including vaccinia virus, measles virus, hepatitis C virus, influenza A virus, and human immunodeficiency virus. Additionally, the mechanism of exclusion has been observed at various steps of the viral life cycle, including attachment, entry, viral genomic replication, transcription, and exocytosis. Human papillomavirus (HPV) is the causative agent of cervical cancer. Recent epidemiological studies indicate that up to 50% women who are HPV positive (HPV⁺) are infected with more than one HPV type. However, no mechanism of superinfection exclusion has ever been identified for HPV. Here, we show that superinfection exclusion exists during a HPV coinfection and that it occurs on the cell surface during the attachment/entry phase of the viral life cycle. Additionally, we are able to show that the minor capsid protein L2 plays a role in this exclusion. This study shows, for the first time, that superinfection exclusion occurs during HPV coinfections and describes a potential molecular mechanism through which it occurs.IMPORTANCE Superinfection exclusion is a phenomenon whereby one cell is unable to be infected by multiple related pathogens. This phenomenon has been described for many viruses and has been shown to occur at various points in the viral life cycle. HPV is the causative agent of cervical cancer and is involved in other anogenital and oropharyngeal cancers. Recent epidemiological research has shown that up to 50% of HPV-positive individuals harbor more than one type of HPV. We investigated the interaction between two high-risk HPV types, HPV16 and HPV18, during a coinfection. We present data showing that HPV16 is able to block or exclude HPV18 on the cell surface during a coinfection. This exclusion is due in part to differences in the HPV minor capsid protein L2. This report provides, for the first time, evidence of superinfection exclusion for HPV and leads to a better understanding of the complex interactions between multiple HPV types during coinfections.

Prospective study of human papillomavirus (HPV) types, HPV persistence, and risk of squamous cell carcinoma of the cervix

BACKGROUND

The link between squamous cell cervical carcinoma and human papillomavirus (HPV) 16/18 is well established, but the magnitude of the risk association is uncertain and the importance of other high-risk HPV (HRHPV) types is unclear.

METHODS

In two prospective nested case-control series among women participating in cytologic screening in Sweden, we collected 2,772 cervical smears from 515 women with cancer in situ (CIS), 315 with invasive squamous cell carcinoma (SCC), and individually matched controls. All smears were tested for HPV with PCR assays, and the median follow-up until diagnosis was 5 to 7 years. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (95% CI).

RESULTS

The presence of HPV16/18 in the first smear was associated with 8.5-fold (95% CI, 5.3-13.7) and 18.6-fold (95% CI, 9.0-38.9) increased risks of CIS and SCC, respectively, compared with women negative for HPV. Infection with other HRHPV types in the first smear was also associated with significantly increased risks for both CIS and SCC. Persistence of HPV16 infection conferred a RR of 18.5 (95% CI, 6.5-52.9) for CIS and 19.5 (95% CI, 4.7-81.7) for SCC. The HPV16/18 attributable risk proportion was estimated at 30% to 50% for CIS, and 41% to 47% for SCC. Other HRHPV types also conferred significant proportions.

CONCLUSIONS

Our large population-based study provides quantification of risks for different HPV types and prospective evidence that non-16/18 HRHPV types increase the risk for future cervical cancer.

IMPACT

This study gives further insights into cervical cancer risk stratification with implications for HPV-based prevention strategies.

Comparison of the hybrid capture II assay with the human papillomavirus DNA chip test for the detection of high-grade cervical lesions

Cervical intraepithelial neoplasia (CIN) 2 is used as the threshold for treatment decisions. This study was conducted to evaluate the clinical efficacy of the Hybrid Capture II assay (HC2) and the human papillomavirus (HPV) DNA chip test (HDC) for detecting HPV in high-grade cervical lesions CIN2 or greater, including adenocarcinoma (CIN2+). Seven hundred forty-one women with abnormal cervical cytology were evaluated with the HC2, the HDC, and histological assessment of the cervix. The overall agreement of the 2 HPV tests was 88.8% (kappa value, 0.61). Of 615 high-risk HPV-positive specimens by the HC2, 571 (92.8%) were HDC-positive. Both tests were performed similarly on CIN2+ samples; the sensitivities of the HC2 and HDC as predictors of CIN2+ were 93.4 and 92.6%, respectively. In 83 cases of discrepancies between the HC2 and HDC, genotyping of 39 HC2-negative/HDC-positive cases revealed 13 HPV-53, 8 HPV-58, 7 HPV-16, 6 HPV-18, 2 HPV-68, 1 HPV-31, 1 HPV-45, and 1 HPV-66. In 515 patients with CIN2+, HPV-16 (45.0%) was the most common type; the next most common types were HPV-58 (20.8%), HPV-18 (16.1%), HPV-31 (6.6%), and HPV-33 (6.6%). Human papillomavirus types 16, 58, and 18 were more likely associated with CIN2+ (P < 0.05). In conclusion, the HDC is a reliable diagnostic tool for the detection of CIN2+. In addition, the HDC provides useful information regarding viral genotypes.

Clinical follow-up of women infected with human papillomavirus-16, either alone or with other human papillomavirus types: identification of different risk groups

OBJECTIVES

Evaluation of the clinical impact of multiple infections of the cervix by human papillomavirus, including human papillomavirus-16, compared with single human papillomavirus-16 infection.

STUDY DESIGN

One hundred sixty-nine women were classified in 3 categories depending on their human papillomavirus profile: human papillomavirus-16 only, human papillomavirus-16 and low-risk type(s), and human papillomavirus-16 and other high-risk type(s). Cervical brush samples were analyzed for human papillomavirus DNA by polymerase chain reaction and reverse line blot hybridization. All women were evaluated with colposcopy during 24 months or more. Management was according to the Bethesda recommendations.

RESULTS

Women infected with human papillomavirus-16 and other high-risk human papillomavirus type(s) presented more progression or no change in the grade of dysplasia, compared with women of the other groups (relative risk [RR], 1.39; 95% confidence interval [CI], 1.07-1.82; P = .02 at 6 months; RR, 2.10; 95% CI, 1.46-3.02; P < .001 at 12 months; RR, 1.82; 95% CI, 1.21-2.72; P = .004 at 24 months).

CONCLUSION

Coinfection of women with human papillomavirus-16 and other high-risk human papillomavirus type(s) increases the risk of unfavorable evolution.

Age-specific prevalence of infection with human papillomavirus in females: a global review

PURPOSE

Global data on age-specific prevalence of human papillomavirus (HPV) infection overall, and for high-risk HPV types 16 and 18, are essential for the future implementation of HPV prophylactic vaccines for cervical cancer prevention.

METHODS

A systematic review of peer-reviewed publications was conducted to summarize worldwide data on genital HPV-DNA prevalence in women. Studies with clear descriptions of polymerase chain reaction or hybrid capture detection assays were included.

RESULTS

A total of 346,160 women were included in 375 studies. Of 134 studies with age-stratified HPV prevalence data (116 low sexual risk populations, 18 high sexual risk populations), over 50% were from Europe and the Middle East (38%) and North America (19%), with smaller proportions from Asia and Australia (21%), Central and South America (11%), and Africa (10%). Across all geographical regions, data on HPV prevalence were generally limited to women over 18 years of age. Consistently across studies, HPV infection prevalence decreased with increasing age from a peak prevalence in younger women (< or =25 years of age). In middle-aged women (35-50 years), maximum HPV prevalence differed across geographical regions: Africa (approximately 20%), Asia/Australia (approximately 15%), Central and South America (approximately 20%), North America (approximately 20%), Southern Europe/Middle East (approximately 15%), and Northern Europe (approximately 15%). Inconsistent trends in HPV prevalence by age were noted in older women, with a decrease or plateau of HPV prevalence in older ages in most studies, whereas others showed an increase of HPV prevalence in older ages. Similar trends of HPV 16 and/or 18 prevalence by age were noted among 12 populations with available data.

DISCUSSION

Genital HPV infection in women is predominantly acquired in adolescence, and peak prevalence in middle-aged women appears to differ across geographical regions. Worldwide variations in HPV prevalence across age appear to largely reflect differences in sexual behavior across geographical regions. Further studies of HPV prevalence in adolescents are needed for all geographic regions.

Comparison of polymerase chain reaction and catalyzed signal amplification in situ hybridization methods for human papillomavirus detection in paraffin-embedded cervical preneoplastic and neoplastic lesions

BACKGROUND

Two molecular methods for HPV genotyping in formalin-fixed, paraffin-embedded tissue were evaluated: in house polymerase chain reaction assay (PCR) with consensus and type-specific primers and a novel procedure of in situ hybridization-a catalyzed signal amplification system (CSA-ISH, Genpoint, DAKO, Glostrup, Denmark). The number of HPV positive cases and detected viral types were compared in cervical biopsies and cone specimens according to histopathological diagnosis. Primer efficiency in detecting various types of HPV by PCR method was evaluated.

METHODS

DNA samples (101) were used as a template to amplify with three pairs of consensus (MY09/11, GP5+/6 +, CPI/IIG) and four type-specific HPV primers (HPV-6/11, 18, 16 and 33). The according histological tissue sections were analyzed with CSA-ISH method, using commercial HPV biotinylated probes HPV-6/11, 16/18 and 31/33/51.

RESULTS

The degree of concordance for PCR and CSA-ISH was 64.4%. In 63 of 101 samples (62.4%), HPV was detected by PCR, while only 35 (34.7%) were positive using CSA-ISH. CSA-ISH found lower percentages for all HPV types, except HPV-6/11. A lower percentage of positive results in all high-grade lesions was detected by CSA-ISH. Multiple infections were detected by PCR in only one sample and in three samples by CSA-ISH. Detection with My09/11 primers followed by Gp5+/6+ primers, in nested reaction, gave the highest number of positive results: 58 of 63 (92%). None of the samples diagnosed as condylomata planum or CIN I was positive for HPV-6/11 (low risk type), which was detected exclusively in condylomata acuminatum group.

CONCLUSIONS

A significantly higher number of positive samples was detected with PCR than with CSA-ISH method. CSA-ISH method should be improved, especially in detecting HPV in high-grade lesions. CSA-ISH may be more accurate in detection of multiple infections. GP5+/6+ in nested reaction after MY09/11 detected the highest number of positive results. Samples diagnosed as benign lesions positive on HPV-X must be monitored as possible candidates for progression. CIN I lesions, which were HPV negative, probably will not progress. This finding may be important in planning therapy and avoiding unnecessary treatment.

Hidradenoma Papilliferum with Oxyphilic Metaplasia

Reported here are 18 cases of hidradenoma papilliferum with oxyphilic metaplasia. All patients were women ranging in age from 29 to 74 years. Each presented clinically with a small, solitary tumor in the anogenital region. Microscopically, in addition to classic histopathological features, in every case there was oxyphilic metaplasia of the constituent epithelial cells. This finding could be likened to apocrine metaplasia, a term used in breast pathology. Other histopathological findings observed in this series, analogous to benign breast disease, included sclerosing adenosis-like changes, atypical apocrine adenosis-like changes, changes corresponding to usual ductal epithelial hyperplasia, epitheliomatosis with a streaming growth pattern, lamprocyte-like changes, clear cell change of the myoepithelium, foamy histiocyte reaction, and stromal fibrosis. Immunohistochemistry inferred that in the majority of cases oxyphilic metaplasia resulted from more lysosomes, whereas numerous mitochondria were detected in only 3 cases. Using 2 different PCR methods we identified HPV in 4 of 15 cases of hidradenoma with oxyphilic metaplasia. In addition, HPV was detected in 3 of 16 conventional papillary hidradenomas used as a control group. The following HPV types were identified: 16, 31, 33, 53, and 56. The last type was found in 5 cases. More than one HPV type from a single lesion was seen in 5 cases. Our observations are consistent with previous publications noting similarities between tumors of the breast and sweat glands. Oxyphilic metaplasia, areas with solid growth, and changes simulating atypical apocrine adenosis are rare and poorly recognized in hidradenoma papilliferum and may cause diagnostic difficulties; in our cases several submitting pathologists suspected malignancy. A causal role for HPV in hidradenoma papilliferum cannot be confirmed from our results, as the detection rate is too low. The exact role of the HPV in etiology and pathogenesis of this neoplasm has yet to be determined.

Eosinophilic dysplasia of the cervix: a newly recognized variant of cervical squamous intraepithelial neoplasia

A proportion of cervical squamous intraepithelial lesions encountered in surgical pathology practice contain both metaplastic features and some degree of atypia [so-called eosinophilic dysplasia (ED)] that defy classification according to established criteria. To elucidate the nature of these lesions, we compared 44 cases of ED to 20 classic high-grade squamous intraepithelial lesions (HSILs) and 10 squamous metaplasias using a panel of biomarkers and human papillomavirus (HPV) testing. EDs were defined as 1) lack of normal maturation; 2) relatively abundant eosinophilic cytoplasm and distinct cell borders compared with conventional HSIL; 3) mildly to moderately increased nuclear to cytoplasmic ratio; and 4) focal dysplastic nuclei showing nuclear enlargement, hyperchromasia, variable nuclear membrane irregularities, and appreciable nucleoli. Expression of p16 (p16), MIB-1 (Ki-67) labeling index, and HPV DNA detection and typing were performed on each case. The majority of EDs showed more than three atypical cells in an entire lesion but lack of apparent features of HSIL. It was common to find neighboring cervical squamous metaplasia and/or conventional SILs (either HSIL or low-grade squamous intraepithelial lesion [LSIL]). Among the 44 cases, 18 (45%) ED lesions were found to be associated with HSIL, 15 (34%) with LSIL or condylomatous lesions, and 13 (30%) EDs were seen without any SILs in the entire specimens. Area of benign squamous metaplasia was found in all ED cases. High levels of p16 and MIB-1 expression were seen in 41 (93%) of 44 ED cases with degrees of immunoreactivity closely resembling those seen with HSIL. Of 16 EDs tested, 13 (81%) were positive for HPV DNAs. Among 10 HPV-positive cases subtyped, 9 (90%) cases contained intermediate- and/or high-risk HPVs and 1 case contained a novel HPV. In the follow-up of pure ED cases, the majority showed presence of dysplastic lesions of either HSIL or LSIL on either loop electric excision procedures or Papanicolaou test samples after a 6- to 10-week period. Therefore, ED represents an unrecognized and potentially clinically significant subgroup of cervical intraepithelial lesions. Based on the unique histologic appearance of ED, its association in some cases with HSIL, the overall immunohistochemical findings, frequent association of ED with intermediate- and/or high-risk HPV infection, and limited follow-up data, we believe that ED represents a variant of HSIL (CIN 2). Since ED possesses histologic features of both dysplasia and metaplasia, we speculate that it may arise from metaplastic cervical squamous epithelium that has subsequently become infected with intermediate- or high-risk HPV.

Comparison of human papillomavirus genotypes in high-grade squamous intraepithelial lesions and invasive cervical carcinoma: evidence for differences in biologic potential of precursor lesions

High-grade squamous intraepithelial lesions of the cervix are heterogeneous in their invasive potential. Comparison of human papillomavirus types between invasive cervical carcinoma and high-grade squamous dysplasia may provide insight into this biological variability. Liquid-based Pap specimens from 55 high-grade intraepithelial lesions and 47 invasive cervical carcinomas were analyzed by reverse line blot for 27 human papillomavirus types designated high, intermediate, or low risk. Human papillomavirus DNA was present in all high-grade intraepithelial lesions (23 different types) and in 94% (13 types) of invasive carcinomas. High-risk types were present in 81% of invasive carcinomas compared to 58% of high-grade intraepithelial lesions. Severe dysplasias harbored more (79%) high-risk human papillomaviruses as compared to moderate dysplasias (37%). In 40% of high-grade dysplasia cases (59% of moderate dysplasias; 21% of severe) and 13% of invasive carcinomas, intermediate-risk genotypes were identified in the absence of high-risk HPV types. Human papillomavirus 16 was the most common type in all categories, including 47% of high-grade squamous dysplasias (26% moderate; 68% severe) and 61% of invasive carcinomas. Both high-risk type (P=0.0004) and type 16 (P=0.0007) human papillomaviruses were positively associated with increasing severity of diagnosis. The heterogeneous nature of high-grade squamous dysplasias as compared to invasive carcinoma is evident by the wider spectrum of associated human papillomavirus types. Likewise, moderate dysplasia appears to be more heterogeneous in viral type than severe dysplasia. Moderate cases were more often associated with intermediate-risk types, while high-risk types were more prevalent in severe dysplasias and invasive cancers. Moderate dysplasia cases harboring viral types infrequently found in cancers may have a low risk for progression. Human papillomavirus genotyping of high-grade squamous intraepithelial lesions may be important in assessing risk for progression to invasion.

Evidence for the coexistence of two genital HPV types within the same host cell in vitro

Studies on the presence of human papillomavirus (HPV) DNA in cervical samples show that 10% or more of all clinical lesions contain at least two different HPV types. We have investigated if multiple HPV types can exist in the same cell and interact with one another or if they merely exist in the same tissue. Combinations of genital HPV genomes were electroporated into primary keratinocytes. Southern analyses of the electroporated cultures indicate that while a subset of high-risk HPV types can be stably maintained and replicate episomally in the same cell, interactions between types do occur, often to the detriment of one or both viruses in question. These studies provide insight into the interactions that may occur between HPV types in naturally occurring lesions.

Moderate variation of the oncogenic potential among high-risk human papillomavirus types in gynecologic patients with cervical abnormalities

The oncogenic potential of human papillomavirus (HPV) infection was assessed by following the disease course in 455 patients who had had a routine diagnostic Hybrid Capture HPV test due to squamous cell abnormalities of the uterine cervix as detected by cytology and/or colposcopy. At entry, 308 patients had cytologic atypia classified as P3 by the Papanicolau classification, 168 had a positive high-risk HPV test, and 23 were infected only with low-risk HPV. The patients were followed-up using the patient registry until the endpoint of histologically diagnosed cervical intraepithelial neoplasia (CIN). High-grade CIN was diagnosed in 75 surgical biopsies. High-risk HPV infection (relative risk: 76.8 CI(95): 23.7-249.5), cytologic atypia (RR: 16.2 CI(95): 3.9-66.6), and age above 35 (RR: 1.99 CI(95): 1.26-3.16) were independent risk factors for high-grade CIN, while the viral load did not predict oncogenic progression (P = 0.47). After PCR-RFLP typing, the high-risk types were classified into groups as follows: (1) types 16 and 18, (2) types 45, 52, and 56, (3) types 31, 33, 35, 51, and 58. The relative risks of high-grade CIN were 119.1 (CI(95): 36.2-390.9) for group 1, 44.4 (CI(95): 9.8-201) for group 2, and 39.7 (CI(95): 10.9-144.8) for group 3, respectively. The risk ratios between the groups of high-risk types were found to differ at most by a factor of 2.98 (corrected P value: 0.007) indicating that the oncogenic potential varies moderately within the high-risk group of HPVs.

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.

Correlation of cervical carcinoma and precancerous lesions with human papillomavirus (HPV) genotypes detected with the HPV DNA chip microarray method

BACKGROUND

Human papillomavirus (HPV) infection is considered to play an important role in the development of cervical carcinoma, and it is known that certain HPV types, such as HPV-16 and HPV-18, are highly associated with cervical carcinoma. However, the pathologic behavior of other HPV types remains unclear. Recently, a new HPV detection technique, the HPV DNA chip, was introduced. The HPV DNA chip harbors 22 HPV probes and has the advantage of being able to detect 22 HPV types simultaneously. To evaluate the quality of the HPV DNA chip method and to identify HPV types related to cervical carcinoma and precancerous lesions, the authors performed HPV typing in cervical specimens from 1983 patients and compared their cytologic and histologic diagnoses.

METHODS

The HPV DNA chip was used for HPV typing. Among 1983 patients who were tested for HPV types, cervical smear cytology was performed in 1650 patients, and 677 of those patients underwent cervical biopsy.

RESULTS

Among the 1650 smears that were examined cytologically, 92.7% (114 of 123 smears) of low-grade squamous intraepithelial lesions (LSILs), 98.1% (106 of 108 smears) of high-grade squamous intraepithelial lesions (HSILs), and 96.3% (51 of 53 smears) of carcinomas were HPV positive, compared with only 35.1% of smears with normal cytology that were HPV positive. HPV-16 was the most prevalent type (chi-square test; P < 0.01) in LSILs (28.5%), in HSILs (51.9%), and in carcinomas (62.5%) followed by HPV-58 and a group of low-risk types (HPV-6, HPV-11, HPV-34, HPV-40, HPV-42, HPV-43,and HPV-44) in LSILs. HPV-58 (15.7%), HPV-18 (6.7%), and HPV-52 (4.6%) were the next most prevalent types after HPV-16 in HSILs. HPV-18 (11.4%) and HPV-58 (11.4%) were the second most common types in carcinomas. HPV-58 had the highest positive predictive value (54.9%) for the detection of histologically confirmed HSIL or carcinoma, whereas HPV 16 had the highest negative predictive value (80.6%). The sensitivity (96.0%) of the HPV test using the DNA chip method for detecting HSIL or carcinoma was superior compared with the sensitivity of cytologic diagnosis (83.6%).

CONCLUSIONS

The HPV DNA chip provides a very sensitive method for detecting 22 HPV genotypes with reasonable sensitivity (96.0%) and reasonable negative predictive value (96.9%), and it overcomes the low sensitivity of cytologic screening for the detection of HSIL or carcinoma. HPV-58, HPV-52, and HPV-56, as well as HPV-16 and HPV-18, were associated highly with HSIL and carcinoma in the current large series. In addition, multiple HPV infection was associated less frequently with cervical carcinoma and with precancerous lesions compared with normal cytology.

Human papillomavirus type 18 and rapidly progressing cervical intraepithelial neoplasia

BACKGROUND

Human papillomavirus type 18 (HPV-18) is the second most frequent of the HPV types detected when squamous-cell cancer is diagnosed and the type most strongly associated with adenocarcinoma of the cervix. However, in cross-sectional studies, HPV-18 is rarely detected at the time of diagnosis of high-grade cervical intraepithelial neoplasia (CIN). We used a longitudinal study design to describe the occurrence of cytological abnormality after incident HPV-18 and HPV-16 infections.

METHODS

The analysis was based on 1075 women aged 15-19 years, who had normal cytology and were negative for HPV at recruitment from a single family-planning clinic, and who had further follow-up. The women reattended every 6 months, and samples were taken for cytological and virological examination.

FINDINGS

The relative risk of a cytological diagnosis of borderline nuclear abnormality after exposure to HPV-18 was 2.06 (95% CI 1.24-3.43) and that after exposure to HPV-16 was 1.99 (1.32-3.01). The relative risks of mild dyskaryosis were 3.11 (1.86-5.18) and 4.76 (3.15-7.18), and the relative risks of moderate or severe dyskaryosis were 0.80 (0.24-2.65) and 2.85 (1.36-5.97). Time to acquisition of cytological abnormality was unrelated to the infecting type (p=0.88).

INTERPRETATION

Our findings do not support the long-held view that the reason why HPV-18 infection is under-represented at the time of diagnosis of high-grade CIN is because HPV-18-associated disease rapidly progresses through the preinvasive stages of neoplasia. We suggest that the cytological changes detected after HPV-18 infection might understate the severity of underlying disease. This feature could compromise the effectiveness of screening programmes in reducing the frequency of HPV-18-associated cancers.

Using a new HPV detection system in epidemiological research: change of views on cervical dyskaryosis?

The prevalence of human papillomavirus (HPV) rises with increasing histological severity of neoplasia, more cigarettes smoked per day and higher lifetime number of sexual partners in women with cervical dyskaryosis. Recently, the highly sensitive SPF10 primers and Inno-LiPA (line probe assay) HPV prototype research assay became available for the detection and typing of HPV.

BACKGROUND

using this system, we challenged the previously reported findings.

STUDY DESIGN

the study group comprised 304 women referred because of abnormal pap smears in whom a histological diagnosis was made. Data on the lifetime number of sexual partners and smoking behaviour were obtained by questionnaire. HPV analysis was performed on cervical scrapes obtained at the enrollment visit.

RESULTS

oncogenic HPV was found in 288 (95%) women. A total of 86 (30%) out of these 288 women disclosed multiple types. HPV 16 occurred significantly less often in multiple infections than was expected on the basis of chance alone. The grade of neoplasia was significantly associated with the presence of oncogenic HPV, and this association depended on the presence of HPV type 16. No association was found between grade of neoplasia and the presence of multiple HPV types. Neither the lifetime number of sexual partners nor smoking were associated with oncogenic HPV, the five most frequent HPV types separately or the presence of multiple types.

CONCLUSION

we conclude that the association between the detection of HPV and the epidemiological risk factors, as found with the GP5/6 PCR in the past, could not be confirmed when using SPF10 PCR primers and LiPA HPV genotyping. We suggest that the number of sexual partners and smoking may be determinants of high HPV viral load rather than determinants of the presence of HPV per se.

Detection of multiple human papillomavirus types in the lower genital tract correlates with cervical dysplasia

Some human papillomavirus (HPV) types, such as HPV 16, are clearly associated with cervical dysplasia; however, the role played by other HPV types occasionally found in dysplasia is less certain. In addition, most methods used to detect HPV in clinical specimens cannot easily distinguish among more than two or three HPV types in a single specimen. Therefore, the significance of infection with multiple HPV types is not known. To address this question, we analyzed cervicovaginal lavage specimens from three cohorts of women for HPV DNA using a PCR/reverse blot assay system that permits the detection and partial quantitation of 26 genital HPV types. As expected, 94.1% of women who had dysplasia (n = 34) and 71.4% of women who had atypical squamous cells of uncertain significance (ASCUS) (n = 21) on cytology had HPV DNA detected compared to 54.5% of age matched women with normal cytology. HPV 16 DNA was detected in 35% of dysplasia patients compared to 9% of cytologic normals (P = 0.0044). Dysplasia patients had a mean of 3.29 (range 0-10) different HPV types detected compared to 1.04 (range 0-7) HPV types among those with normal cytology (P < 0.0001). These data support a possible role for multiple HPV types in the development or progression of cervical dysplasia.

Human papillomavirus infections: epidemiology, pathogenesis, and therapy

BACKGROUND

Human papillomaviruses (HPV) are common human pathogens and are classified into more than 80 different types. These viruses produce benign warts in many cases and aggressive squamous cell carcinomas in other cases.

OBJECTIVE

The goal of this review is to update the reader on the epidemiology, pathogenesis, and therapy of HPV infections. Nonanogenital warts are transmitted by skin-to-skin contact while anogenital warts are usually transmitted sexually. Both types of warts produce much morbidity but rarely undergo malignant transformation. They are commonly treated with surgical or cytodestructive therapy, but immunomodulatory agents, such as imiquimod, have been proven to be very effective in anogenital warts and are being evaluated in nonanogenital warts. Other types of HPV have marked oncogenic potential such that over 99% of all cervical cancers and over 50% of other anogenital cancers are due to infection with oncogenic HPV. Many cofactors, such as cigarette smoking, genetics, and helper viruses, have potential roles in HPV oncogenesis, but their relative contributions are poorly understood. Other control measures for warts and HPV-associated cancers are under study, but the greatest future potential may be from the development of prophylactic and therapeutic vaccines.

CONCLUSIONS

Infection with HPV is very prevalent as are the clinical manifestations of this family of pathogens. Improved therapies for warts (e.g., imiquimod) have recently become available. Vaccines for HPV offer hope for future interventions for warts as well as for prevention of anogenital malignancies.

Amplification with molecular beacon primers and reverse line blotting for the detection and typing of human papillomaviruses

A novel method for the detection and typing of human papillomavirus (HPV) was developed using molecular beacon primers. The method is based on the use of HPV-specific primers containing a hairpin loop structure in which fluorescent donor and quencher groups are held in close proximity such that fluorescence is quenched. Amplification of the target sequence results in the opening of the loop and the resulting fluorescence can be detected on a sequence detector system (SDS) 7700 (Applied Biosystems), as used for TaqMan assays. Fluorescent amplicons were identified on the SDS 7700 and then typed by a single hybridisation with specific probes immobilised in lines on a nylon membrane and detected on a fluorescent scanner. This novel beacon primer method compared well with conventional PCR for cervical scrape specimens. The combination of the beacon primer method and reverse line blotting should enable large-scale population studies of HPV infection.

Single-tube real-time nested polymerase chain reaction for detecting human papillomavirus DNA

A single-tube real-time nested polymerase chain reaction (PCR) was developed to detect human Papillomavirus (HPV) DNA in a closed tube system. The oligonucleotide primers MY09/MY11 and GP5+/GP6+ were included in contiguous reactions, thus eliminating the need to transfer first round PCR product into a second tube. The sensitivity and specificity of the optimized single-tube nested PCR were comparable with that achieved by two separate reactions on a conventional thermal block system using serial dilutions derived from plasmids containing DNA of 20 HPV types. A minimum of 10 copies of HPV types 11 and 16 DNA could be detected by both systems. In clinical samples, HPV types 1A, 2, 3, 5, 6-8, 10, 11, 14, 16, 17, 18, 20, 31, 33, 35, 39, 45, 49, 50, 52-54, 57, 62, 66, 70, CP8304 and LVX82/MM7 could be detected by both PCR methods. A total of 145 samples collected from patients were tested for the presence of HPV DNA with the two PCR systems; 124 (86.1%) of 144 samples gave concordant results in both assays. The HPV DNA positive PCR amplicons were typed and concordant results were obtained in 47 of 67 positive samples tested in both amplicons. In samples containing multiple HPV types at least one type was common to both amplicons.

Population-based study of human papillomavirus infection and cervical neoplasia in rural Costa Rica

BACKGROUND

Human papillomavirus (HPV) is the main cause of cervical neoplasia. Because few population-based studies have investigated the prevalence of type-specific infection in relation to cervical disease, we studied a high-risk population, estimating the prevalence of HPV infection and the risk associated with various HPV types.

METHODS

We screened 9175 women in Guanacaste, Costa Rica, to obtain a referent standard final diagnosis, and tested 3024 women for more than 40 types of HPV with a polymerase chain reaction-based system.

RESULTS

Among women with normal cytology, HPV infections peaked first in women younger than 25 years, and they peaked again at age 55 years or older with predominantly non-cancer-associated types of HPV and uncharacterized HPV types. Low-grade squamous intraepithelial lesions (LSILs) (n = 189) decreased consistently with age. The prevalence of high-grade squamous intraepithelial lesions (HSILs) (n = 128) peaked first around age 30 years and again at age 65 years or older. Seventy-three percent of LSILs were HPV positive, with HPV16 being the predominant type (16% of positive subjects). HPV was found in 89% of HSILs and 88% of cancers, with HPV16 being strongly predominant (51% and 53% of positive subjects). Virtually all HSILs and cancers had cancer-associated HPV types, with high odds ratios (ORs) and attributable fractions around 80%. Risk for HPV16 was particularly high (OR for HSILs = 320, 95% confidence interval [CI] = 97-1000; OR for cancer = 710, 95% CI = 110-4500).

CONCLUSIONS

We confirm the early decline of HPV infection with age but note increased prevalence after menopause, which could be related to a second peak of HSILs, an observation that warrants further investigation. At least 80% of HPVs involved in cervical carcinogenesis in this population have been characterized. Polyvalent vaccines including the main cancer-associated HPV types may be able to prevent most cases of cervical disease in this region.

Is human papillomavirus testing of value in clinical practice?

The objective of this review was to evaluate the current status of human papillomavirus testing in predicting the presence of high-grade or invasive disease in the cervix in women with Papanicolaou smears reported as atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion. This is a review of many of the studies already published evaluating the utility of human papillomavirus testing as part of the triage for patients whose Papanicolaou smears were reported as ASCUS or low-grade squamous intraepithelial lesion. Two triage approaches for follow-up of such patients are presented, and recommendations are made as to which is most cost-effective and safe. Data related to human papillomavirus testing were obtained with both currently available commercial kits for detection of high-risk human papillomavirus and the polymerase chain reaction. There was variation in results reported, possibly related to populations studied. The approach to management by cytologic screening and colposcopy, when indicated, appeared over the long term to be equal to human papillomavirus testing. In our opinion current human papillomavirus testing is of little clinical use to the practitioner. Its use should be limited to appropriately designed and implemented research studies.

Detection of human papillomavirus DNA in urinary bladder carcinoma by in situ hybridisation

AIMS

To investigate the sensitivity of an in situ hybridisation system to detect human papillomavirus (HPV) infection in transitional cell bladder cancer and to evaluate the advantages of analysing multiple biopsies; to examine the correlation between HPV tumour infection detected by in situ hybridisation and the presence of serum anti-HPV antibodies detected by enzyme linked immunosorbent assay (ELISA); and to relate the presence of viral infection to grade, stage, and follow up in cases of bladder cancer.

METHODS

The in situ hybridisation technique was used with broad spectrum and type specific (6/11, 16/18, 31/33/35) probes against HPV DNA in formalin fixed, paraffin embedded tissues from 43 cases of bladder cancer. The results were analysed for the presence and type of papillomavirus and correlated with clinicopathological variables.

RESULTS

The presence of HPV DNA was identified by the in situ hybridisation technique in 17 of 43 cases of bladder cancer; 12 of these were serum antibody positive and 10 had had multiple biopsies. Fifteen of the cases that were negative for HPV DNA by in situ hybridisation had positive serum serology when tested by ELISA. In 14 cases, the HPV was either types 16/18 or types 31/33/35, both of which carry high oncogenic risk. The stage (p < 0.05) and grade (NS) of the tumour and the outcome on follow up (p < 0.05) were correlated with the presence of HPV infection.

CONCLUSIONS

ELISA is not useful in identifying patients with HPV positive bladder cancer, but the use of several probes and multiple biopsies increases the detection rate of HPV in neoplastic tissues. The association between tumour virus infection and high grade/high stage tumours and worse outcome suggests that HPV infection of neoplastic tissue has a negative effect on the behaviour and evolution of transitional cell bladder carcinoma.

Virological and biological characteristics of cervical intraepithelial neoplasia grade I with marked koilocytotic atypia

The aim of this study was to evaluate virologic and biological significance of marked koilocytotic atypia observed in some cases of grade I cervical intraepithelial neoplasia (CIN I). Thirty-one CIN I cervical biopsy specimens with marked koilocytotic atypia, defined by the presence of meganuclei in the superficial epithelial layers, were compared to 37 CIN I biopsy specimens with usual koilocytes for (1) the human papillomavirus (HPV) type and signal pattern as detected by nonisotopic in situ hybridization (ISH); (2) the proliferation index assessed by Ki 67 immunostaining and (3) the p53 labeling pattern. Interobserver agreement for meganuclei was excellent (k = 0.9). Twenty-five out of 68 biopsies (37%) were positive by ISH for the 6 of 11 HPV probe, 30 (44%) for the 16-18 probe, and 7 (10%) for the 31/33 HPV probe, 6 (9%) were negative for ISH. The presence of meganuclei was strongly related to high and intermediate risk HPV type (P = 0.0001). The sensitivity and specificity of meganuclei for the detection of high or intermediate risk HPV in CINI were 73 and 87%, respectively. Loss of p53 immunostaining in the lower third of the epithelium was also related to the presence of meganuclei (P < .05), but the MIB-1 index and ISH labeling pattern were not. In conclusion, marked koilocytotic atypia in CIN I is a reliable and sensitive marker for infection by high or intermediate-risk HPV, and might be a guide to therapy.