Different detectability of high-risk HPV in smears from incident and prevalent high-grade squamous intraepithelial lesions of the cervix

Comparison of the hybrid capture test and polymerase chain reaction in identifying women who have an atypical squamous cell of undetermined significance papanicolaou smear and need colposcopy

OBJECTIVES

The objective of this study was to detect human papillomavirus (HPV) in women with a newly diagnosed atypical squamous cells of undetermined significance (ASCUS) using the hybrid capture (HC) test and the polymerase chain reaction (PCR). We sought to evaluate the accuracy of both tests in identifying women with a concomitant cervical intraepithelial neoplasia (CIN).

MATERIALS AND METHODS

We studied 360 women who had a diagnosis of ASCUS and were referred to the colposcopy clinic. Subjects were between 18 and 50 years, had newly diagnosed ASCUS, had no history of cervical biopsies or treatment, and were not pregnant. A cell sample for HPV testing and colposcopically directed biopsies of lesions were obtained. HPV was detected using the Digene HC and PCR systems (Digene, Silver Spring, MD).

RESULTS

Biopsies showed concomitant CIN in 80 patients (22.2%). Of these, 19 had CIN2 or CIN3. HPV-DNA was detected in 76 of the 360 women (21.1%) using HC and in 166 of 348 women (47.7%) using PCR. The concordance between HC and PCR for detecting HPV was 65%. The sensitivity, specificity, and positive and negative predictive values of HC for detecting CIN were 48%, 86%, 50%, and 85%, respectively. The sensitivity, specificity, and positive and negative predictive values of PCR for detecting CIN were 67%, 58%, 31%, and 86%, respectively. Focusing on CIN2 and CIN3 alone, these values were 79%, 82%, 20%, and 99% for HC, respectively, and 89%, 55%, 10%, and 99% for PCR, respectively.

CONCLUSION

The specificity of HC was higher than the specificity of PCR. For this reason, the HC might be more useful than PCR as a secondary triage method for detecting CIN in women who have incident ASCUS and need colposcopy.

Worldwide incidence of cervical lesions: a systematic review

We conducted a systematic review summarizing data on incidence of high- and low-grade lesions in women with normal baseline cervical cytology, stratified by age (<30 and ⩾30 years), and baseline human papillomavirus (HPV) infection. Incidence of high- and low-grade lesions in women aged ⩾30 years with a baseline HPV infection increased over follow-up time (5-127 months), although incidence generally remained <10%. Without baseline HPV infection, incidence of high-grade lesions remained low over follow-up time (<5% over 5-122 months). Incidence of high-grade lesions in women aged ⩾30 years with baseline HPV infection appeared similar to that in women aged <30 years. In some women aged <30 years, high-grade lesions can develop relatively shortly after initial HPV infection. We observed an increase in low-grade lesions over time in women aged ⩾30 years with baseline HPV infection, potentially indicative of an HPV infection that is potentially progressing to higher grade lesions.

Assessment of MagNA pure LC extraction system for detection of human papillomavirus (HPV) DNA in PreservCyt samples by the Roche AMPLICOR and LINEAR ARRAY HPV tests

Roche Molecular Systems recently released two PCR-based assays, AMPLICOR and LINEAR ARRAY (LA), for the detection and genotyping, respectively, of human papillomaviruses (HPVs). The manual specimen processing method recommended for use with both assays, AmpliLute, can be time-consuming and labor-intensive and is open to potential specimen cross-contamination. We evaluated the Roche MagNA Pure LC (MP) as an alternative for specimen processing prior to use with either assay. DNA was extracted from cervical brushings, collected in PreservCyt media, by AmpliLute and MP using DNA-I and Total Nucleic Acid (TNA) kits, from 150 patients with histologically confirmed cervical abnormalities. DNA was amplified and detected by AMPLICOR and the LA HPV test. Concordances of 96.5% (139 of 144) (kappa=0.93) and 95.1% (135 of 142) (kappa=0.90) were generated by AMPLICOR when we compared DNA extracts from AmpliLute to MP DNA-I and TNA, respectively. The HPV genotype profiles were identical in 78.7 and 74.7% of samples between AmpliLute and DNA-I or TNA, respectively. To improve LA concordance, all 150 specimens were extracted by MP DNA-I protocol after the centrifugation of 1-ml PreservCyt samples. This modified approach improved HPV genotype concordance levels between AmpliLute and MP DNA-I to 88.0% (P=0.043) without affecting AMPLICOR sensitivity. Laboratories that have an automated MP extraction system would find this procedure more feasible and easier to handle than the recommended manual extraction method and could substitute such extractions for AMPLICOR and LA HPV tests once internally validated.

Relationships of Human Papillomavirus Type, Qualitative Viral Load, and Age with Cytologic Abnormality

Persistent cervical infections with carcinogenic human papillomaviruses (HPV) cause virtually all cervical cancer. Cytologic abnormalities are the manifestations of HPV infections used to identify women at risk. To compare the potential of the full range of anogenital HPV genotypes to induce cytopathic effects, we examined the influences of HPV type, viral load, and age on cytopathology among 1,222 women having a single HPV type at enrollment into a 10,000-woman population-based study in Costa Rica. Cervical specimens were tested for approximately 40 HPV types by MY09/MY11 L1 primer PCR and type-specific dot blot hybridization. Types were organized by phylogenetic species and cancer risk. PCR signal strength served as a qualitative surrogate for viral load. Overall, 24.8% [95% confidence interval (95% CI), 22.4-27.3] of single prevalent HPV infections had concurrent abnormalities (atypical squamous cells or worse) ranging from 0.0% to 80.0% based on HPV type. Noncarcinogenic alpha3/alpha15 types, although highly prevalent, uncommonly caused cytologic abnormalities (13.1%; 95% CI, 9.8-17.0). In contrast, one quarter to nearly one half of infections with a single major carcinogenic species type (alpha9/alpha11/alpha7/alpha5/alpha6) produced abnormalities. Greater abnormalities were observed with increasing qualitative viral load of carcinogenic types; fewer abnormalities were observed among older women (>54 years). A high percentage (46.2%) of detected abnormalities in women infected with HPV16 or related alpha9 types were high grade or worse, consistent with strong carcinogenicity, compared with 10.7% in women infected with alpha7 types, including HPV18, a major cause of adenocarcinoma. The lack of evident severe abnormalities associated with HPV18 and related HPV types might have implications for screening for poorly detected glandular and alpha7-related lesions.

Associations of high-risk HPV types and viral load with cervical cancer in China

BACKGROUND

Cervical cancer is the second most common cancer in women worldwide. Infection with some genotypes of human papillomavirus is the most important risk factor associated with cervical cancer.

OBJECTIVE

The aim of this study was to determine the prevalence and genotypes of HPV in China, and to evaluate the correlation between viral load of high risk HPV and cervical cancer and its precursors.

STUDY DESIGN

A cross-sectional study was carried out, wherein cervical samples were collected from 541 patients with cervical cancer, 262 with CIN, 139 with cervicitis and 68 age-matched healthy controls. Hybrid Capture 2 was employed to detect HPV DNA. Specimens from HPV DNA positive cervical cancer were tested for HPV types by using type specific PCR and general primer PCR with sequence-based typing (GP PCR-SBT).

RESULTS

Overall high risk HPV prevalence was 68.8% in CIN1, 80.3% in CIN2, 90.2% in CIN3, 90.9% in cervical cancer in situ, 89.9% in invasive cervical cancer and 25% in healthy controls from China. The most common HPV DNA type found in patients with cervical cancer was HPV16 (79.6%), followed by HPV58 (5.92%), HPV33 (3.29%), HPV18 (1.97%), HPV6 (1.97%), HPV31 (1.31%), HPV39 (1.31%), HPV68 (1.31%) and other HPV types (3.3%). It was found that there was a significantly increased risk of increasing CIN stage with high viral load. Frequency of low viral load found in the controls was 13.2% and 22.9% of CIN1, obtaining an OR of 4.2 (1.5-12.0). Associations (OR) among low viral load and CIN2/3, CIS, and CC were 6.7 (2.9-15.6), 9.4 (2.7-32.3) and 8.3 (3.7-18.4), respectively. While high viral loads were found in 5.9% of controls, 27.1% of CIN1, 42.1% of CIN2/3 and 48.5% of CIS, demonstrating increasing odds ratios with severity of disease (OR for CIS=68.0, 95% CI=17.8-259.7).

CONCLUSIONS

HPV16 was the most common genotype in central China. The developing cervical cancer precursors were associated with elevated high-risk HPV viral load.

Type-specific associations of human papillomavirus load with risk of developing cervical carcinomain situ

We have previously shown that high human papillomavirus (HPV) 16 load in Papanicolaou smears negative for dysplasia is strongly associated with risk for carcinoma in situ (CIS) of the cervix. Here we study the amount of HPV DNA for some of the most frequent high-risk HPV types as determinants of progression to cervical CIS. Real-time PCR is used to estimate the normalized viral load of HPV 16, 18, 31, 33, 35, 39, 45, 52, 58 and 67 in 457 cases of cervical CIS and 552 matched population controls. A total of 2,747 archival Pap smears from gynecologic health examinations, collected over a period of up to 26 years, were analyzed to assess viral load during the infection history. Cervical smear samples differ widely in amount of DNA, underscoring the need for normalization of HPV load to number of cells in the sample. The risk of developing cervical CIS increases with higher viral load for most of the HPV types studied. The range of copy numbers per cell does not differ between HPV types but the odds ratio for CIS in the percentile with highest viral load is substantially higher for HPV 16 (OR = 36.9; 95% CI = 8.9-153.2) than for HPV 31 (OR = 3.2; 95% CI = 1.1-9.1) or HPV 18/45 (OR = 2.6; 95% CI = 1.0-6.4). Therefore, HPV viral load may be predictive of future risk of cervical CIS at a stage when smears are negative for squamous abnormalities, but differences between HPV types need closer attention.

Real-time PCR assays using internal controls for quantitation of HPV-16 and β-globin DNA in cervicovaginal lavages

High-risk human papillomavirus 16 (HPV-16) DNA viral load has been measured with real-time PCR assays by amplifying HPV-16 and a human gene. However, these assays have not used internal controls (ICs) to screen for the presence of inhibitors contained in samples. To quantitate HPV-16 DNA and cell content with real-time PCR, ICs for HPV-16 DNA and beta-globin were synthesised and used to control for inhibition. The assays were sensitive and linear over 5 logs. Good reproducibility was achieved with inter-run coefficients of variation of 23% (10(2) HPV-16 copies), 12% (10(4) HPV-16 copies), 17% (274 beta-globin DNA copies) and 7% (27,400 beta-globin DNA copies). Samples containing 56,800,000, 306,000, 18,000, and 4,070 HPV-16 copies/microg of cellular DNA were tested blindly and estimated to contain 48,800,000, 479,000, 20,300, and 6,620 HPV-16 copies/microg of DNA (mean ratio of measured to expected viral load of 1.27+/-0.32). Inhibition of amplification of HPV-16 and beta-globin ICs by six samples known to contain PCR inhibitors was variable: four inhibited both ICs while two inhibited only the HPV-16 IC. The use of internal controls with real-time PCR for HPV-16 quantitation allows to screen for the presence of inhibitors that do not affect equally primer-driven genomic amplification.

Viral load as a predictor of the risk of cervical intraepithelial neoplasia

HPV infections are believed to be a necessary cause of cervical cancer. Viral burden, as a surrogate indicator for persistence, may help predict risk of subsequent SIL. We used results of HPV test and cytology data repeated every 4-6 months in 2,081 women participating in a longitudinal study of the natural history of HPV infection and cervical neoplasia in São Paulo, Brazil. Using the MY09/11 PCR protocol, 473 women were positive for HPV DNA during the first 2 visits. We retested all positive specimens by a quantitative, low-stringency PCR method to measure viral burden in cervical cells. Mean viral loads and 95% CIs were calculated using log-transformed data. RRs and 95% CIs of incident SIL were calculated by proportional hazards models, adjusting for age and HPV oncogenicity. The risk of incident lesions increased with viral load at enrollment. The mean number of viral copies/cell at enrollment was 2.6 for women with no incident lesions and increased (trend p = 0.003) to 15.1 for women developing 3 or more SIL events over 6 years of follow-up. Compared to those with <1 copy per cell in specimens tested during the first 2 visits, RRs for incident SIL increased from 1.9 (95% CI 0.8-4.2) for those with 1-10 copies/cell to 4.5 (95% CI 1.9-10.7) for those with >1,000 copies/cell. The equivalent RR of HSIL for >1,000 copies/cell was 2.6 (95% CI 0.5-13.2). Viral burden appears to have an independent effect on SIL incidence. Measurement of viral load, as a surrogate for HPV persistence, may identify women at risk of developing cervical cancer precursors.

[Human papillomavirus typing in routine cervical smears. Results from a series of 3778 patients]

AIM

As human papillomavirus (HPV) infection is a significant risk factor for cervical cancer, the aim of this study was to assess the efficacy of HPV detection techniques in predicting the presence or the development of a high-grade squamous intra epithelial lesion. Additional reasons for carrying out this investigation were as follows. It was considered that the clinical value of HPV typing may have been underestimated in certain previous reports, which based their findings on first-generation assays. Moreover, until the present investigation most studies only investigated the cases with abnormal smear findings and did not include long-term follow-up, nor detailed follow-up of women with a normal smear but positive HPV typing, although this patient subgroup is of particular interest. The patient population included 3778 women who underwent routine cytological cervical screening and who gave their informed consent to participate in this study, consisting of a cervical smear, HPV testing via a second-generation Hybrid Capture II assay (which is more sensitive than first-generation tests, and can detect 18 different HPV types, i.e., 13 oncogenic and five non-oncogenic types); and in the case of abnormal smear findings, colposcopic examination and directed biopsies of the sites of suspected lesions. The women with cytomorphologically normal cervical smears but which who HPV-positive were reexamined six months later.

RESULTS

HPV findings were positive in 66 cases where the initial smear indicated the presence of a high-grade lesion with the diagnosis confirmed by biopsy in 65 cases; in 155 cases (76.1%) where the initial smear indicated the presence of a low-grade lesion; in 44 (57.1%) out of 77 smears indicating the presence of ASCUS-type (atypical squamous cells of undetermined significance) lesions; and in 366 cases (10.5%) of apparently normal initial smears. After colposcopy and follow-up, a final diagnosis of high-grade lesion was made for 85 patients. All these patients were found to have high-risk (oncogene-positive) HPV at the first examination, but in only 65 cases (76.5%) was the initial smear indicative of a high-grade lesion. Finally, in the patient groups with low-grade or ASCUS-type smear findings or with an apparently normal smear, a high-grade lesion was only found in those patients with persistent high-risk HPV infection. In all, the sensitivity of the Hybrid Capture II assay in detecting high-grade lesions was 100% versus 85.9% for standard cytology. However, its specificity (86.3%) and positive predictive value were not as high as the latter.

CONCLUSION

The results of this study indicate that HPV typing via this second-generation assay displays good sensitivity for the detection of at-risk cases, i.e., those involving the presence or development of high-grade cervical lesions. However, a number of issues have to be addressed before HPV typing is adopted in clinical practice, such as the fairly high HPV prevalence in women aged over 60 years, and whether the implications of this are the same as for younger age groups. Also, the present cost of complete typing remains too high for it to be used on a widespread scale. Nevertheless, HPV typing may have a useful role to play in the detection of cervical cancer.

Papillomavirus detection: demographic and behavioral characteristics influencing the identification of cervical disease

OBJECTIVE

This study was undertaken to assess the association between detection of high-risk types of human papillomavirus and various demographic and behavioral characteristics and to further relate this association to cervical histopathologic findings.

STUDY DESIGN

A total of 1007 patients with a Papanicolaou test result reported as high-grade squamous intraepithelial lesion or with 2 results reported as atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion were referred from city and county clinics to a colposcopic clinic. All women had a cervical smear obtained, underwent colposcopically directed biopsy and endocervical curettage, and had a specimen taken for human papillomavirus deoxyribonucleic acid detection by polymerase chain reaction. Demographic information was obtained from each patient.

RESULTS

Human papillomavirus deoxyribonucleic acid was identified in 655 (66%) of the specimens. High-risk human papillomavirus types (16, 18, 31, 33, and 35) were detected in 463 (70.7%) of these specimens. The prevalence of evidence of human papillomavirus (koilocytosis) and grade 1 cervical intraepithelial neoplasia in the biopsy specimen decreased significantly with age, whereas the prevalence of grade 2 or 3 cervical intraepithelial neoplasia in the biopsy specimen increased with age. There was a significant age-dependent decreasing trend in detection of high-risk human papillomavirus deoxyribonucleic acid among women who had human papillomavirus-associated changes, grade 1 cervical intraepithelial neoplasia, and grade 2 or 3 cervical intraepithelial neoplasia in the biopsy specimen. The prevalences of high-risk human papillomavirus among patients with grade 1 cervical intraepithelial neoplasia and grade 2 or 3 cervical intraepithelial neoplasia were similar, and both were significantly higher than among women with no evidence of cervical intraepithelial neoplasia or koilocytosis in the biopsy specimen. Risk factors associated with grade 2 or 3 cervical intraepithelial neoplasia were different from those associated with human papillomavirus-associated changes and with grade 1 cervical intraepithelial neoplasia.

CONCLUSION

The detection of high-risk human papillomavirus was age-dependent for all histologic categories. Patients with grade 2 or 3 cervical intraepithelial neoplasia had a prevalence of high-risk human papillomavirus that was similar to that among women with grade 1 cervical intraepithelial neoplasia but significantly higher than that among women whose biopsy specimens appeared normal or demonstrated only the presence of human papillomavirus-induced changes (koilocytosis). This suggests that separation of human papillomavirus-associated changes only from grade 1 cervical intraepithelial neoplasia may be of significance in tissue diagnosis.

Chlamydia trachomatis infection in women with and without cervical intraepithelial neoplasia

The aim of the study was to compare the frequency of Chlamydia trachomatis infection in patients with cervical intraepithelial neoplasia (CIN) and in women without cervical pathology. In a study group of 423 patients with histologically proven CIN and in 108 controls with normal cervical smear, cytological material for direct immunofluorescence analysis was obtained. Among 423 patients, 24 (5.7%) had CIN 1, 108 (25.5%) CIN 2 and 291 (68.8%) CIN 3. Among all patients with CIN, 27 (6.4%) were C. trachomatis positive and 396 (93.6%) C. trachomatis negative. In the control group 6 (5.6%) were C. trachomatis positive and 102 (94.4%) C. trachomatis negative. The difference between C. trachomatis infection incidence in patients with CIN and in women without cervical pathology was not significant (chi2=0.29; P>0.05). In this study, no difference in C. trachomatis infection incidence was detected between patients with CIN and women with normal cervical smears. The impact of C. trachomatis infection seems not to interfere with the development or even the promotion of CIN.

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 and identification of human papilloma viral DNA, types 16, 18, and 33, by a combination of polymerase chain reaction and a colorimetric solid phase capture hybridisation assay

A colorimetric microplate hybridization assay was developed previously to simplify detection procedures of DNA fragments resulting from polymerase chain reactions (PCR). This format has now been adapted for the simultaneous detection and identification of three human papillomavirus (HPV), types 16, 18 and 33, associated frequently with cervical cancer. This post-PCR detection system uses three type-specific capture oligonucleotides linked covalently to a single microplate well and three type-specific multibiotinylated oligonucleotidic probes for detection. It therefore offers a double specificity; the first is conferred by pairs of primers, specific of each type of virus tested, and the second, by the sets of capture and detection probes which are complementary to internal regions of the amplified DNA fragments. The detection format outperformed agarose gel electrophoresis of amplified DNA products in sensitivity and specificity. The rapidity and simplicity of this hybridisation system would justify its use in routine diagnostic examination of cervical specimens (smears and biopsies).