Squamous Intraepithelial Lesion Triage Study Research Articles

Type-dependent association between risk of cervical intraepithelial neoplasia and viral load of oncogenic human papillomavirus types other than types 16 and 18.

Studies of the clinical relevance of human papillomavirus (HPV) DNA load have focused mainly on HPV16 and HPV18. Data on other oncogenic types are rare. Study subjects were women enrolled in the atypical squamous cells of undetermined significance (ASC-US) and low-grade squamous intraepithelial lesion (LSIL) triage study who had ≥1 of 11 non-HPV16/18 oncogenic types detected during a 2-year follow-up at 6-month intervals. Viral load measurements were performed on the first type-specific HPV-positive specimens. The association of cervical intraepithelial neoplasia grades 2-3 (CIN2/3) with type-specific HPV DNA load was assessed with discrete-time Cox regression. Overall, the increase in the cumulative risk of CIN2/3 per 1 unit increase in log10 -transformed viral load was statistically significant for four types within species 9 including HPV31 (adjusted hazard ratio [HR adjusted ] = 1.32: 95% confidence interval [CI], 1.14-1.52), HPV35 (HR adjusted = 1.47; 95% CI, 1.23-1.76), HPV52 (HR adjusted = 1.14; 95% CI, 1.01-1.30) and HPV58 (HR adjusted = 1.49; 95% CI, 1.23-1.82). The association was marginally significant for HPV33 (species 9) and HPV45 (species 7) and was not appreciable for other types. The per 1 log10 -unit increase in viral load of a group of species 9 non-HPV16 oncogenic types was statistically significantly associated with risk of CIN2/3 for women with a cytologic diagnosis of within normal limits, ASC-US, or LSIL at the first HPV-positive visit but not for those with high-grade SIL. Findings suggest that the viral load-associated risk of CIN2/3 is type-dependent, and mainly restricted to the species of HPV types related to HPV16, which shares this association.

Association of Human Papillomavirus 31 DNA Load with Risk of Cervical Intraepithelial Neoplasia Grades 2 and 3.

The association between human papillomavirus 31 (HPV31) DNA loads and the risk of cervical intraepithelial neoplasia grades 2 and 3 (CIN2-3) was evaluated among women enrolled in the atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL) triage study (ALTS), who were monitored semiannually over 2 years and who had HPV31 infections detected at ≥1 visit. HPV31 DNA loads in the first HPV31-positive samples and in a random set of the last positive samples from women with ≥2 HPV31-positive visits were measured by a real-time PCR assay. CIN2-3 was histologically confirmed at the same time as the first detection of HPV31 for 88 (16.6%) of 530 women. After adjustment for HPV31 lineages, coinfection with other oncogenic types, and the timing of the first positive detection, the odds ratio (OR) per 1-log-unit increase in viral loads for the risk of a concurrent diagnosis of CIN2-3 was 1.5 (95% confidence interval [CI], 1.2 to 1.9). Of 373 women without CIN2-3 at the first positive visit who had ≥1 later visit, 44 had subsequent diagnoses of CIN2-3. The initial viral loads were associated with CIN2-3 diagnosed within 6 months after the first positive visit (adjusted OR, 1.5 [95% CI, 1.0 to 2.4]) but were unrelated to CIN2-3 diagnosed later. For a random set of 49 women who were tested for viral loads at the first and last positive visits, changes in viral loads were upward and downward among women with and without follow-up CIN2-3 diagnoses, respectively, although the difference was not statistically significant. Results suggest that HPV31 DNA load levels at the first positive visit signal a short-term but not long-term risk of CIN2-3.

Abstract 852: Smoking and HPV antibodies, a mediation analysis of HPV re-infection

Abstract Background: Naturally acquired antibodies against human papillomavirus (HPV) infection can protect against recurring infection. Smoking can adversely affect a person's immune response, both adaptive and innate systems; and it is also associated with increased risk of HPV-related precancers. But, it is unclear whether smoking results in higher HPV incidence because of an impaired immune response. Objective: We investigated whether lowered HPV-16 antibody titers mediates the effect of smoking on incident HPV-16 infection. Methods: We used a path analytic model where smoking lowers a person's antibody titer, thereby resulting in a higher risk of acquiring an incident re-infection. The model estimated the indirect effect of smoking to infection, mediated by antibodies; it also estimated the direct effect, which is not mediated. The path model includes two logistic equations with effects and confidence intervals estimated by parametric bootstrapping. Both equations were adjusted for age, age at sexual initiation, lifetime number of sexual partners, and ever diagnosis of a sexually transmitted infection other than HPV. Study Population: A subset of women in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study provided blood samples at baseline. The samples were assessed for HPV antibodies using a multiplex Luminex assay. Smoking and sexual habits were assessed by a baseline questionnaire. During two years of follow-up, bi-annual cervical specimens were genotyped for HPV by PCR assays. The analytic population (n = 1,978) were women without a cervical intraepithelial lesion grade 2 or more severe and HPV-16 DNA negative at baseline. Among those women, 131 tested HPV-16 DNA positive during follow-up. Results: Compared to never smokers, current smokers had an increased risk of incident HPV-16 infection by the antibody mediated pathway (OR = 1.24, 95% CI: 1.08, 1.60); the direct effect was non-significant. For former smokers, neither direct nor indirect effects were significant. The indirect effect of current smoking increased for women who smoked at least half a pack of cigarettes daily (OR = 1.47, 95% CI: 1.20, 2.02). Conclusions: This is the first analytic model to suggest that current smoking increases the risk of incident HPV-16 infection through a reduction of HPV-16 antibody titers. The association appears dose-dependent, increasing for number of cigarettes smoked per day. Because our follow-up time was limited, we could not measure, and thus, extend these results to incident precancer outcomes. Citation Format: Ronald C. Eldridge, Michael Pawlita, Lauren Wilson, Philip E. Castle, Tim Waterboer, Patti E. Gravitt, Mark Schiffman, Nicolas Wentzensen. Smoking and HPV antibodies, a mediation analysis of HPV re-infection. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 852. doi:10.1158/1538-7445.AM2015-852

Functional variants in CYP1A1 and GSTM1 are associated with clearance of cervical HPV infection

ObjectiveWe evaluated time to clearance of high risk (HR) HPV infection in relation to functional variants in three genes (CYP1A1, GSTT1, and GSTM1). MethodsThe study group consisted of 450 HR-HPV infected women from the Atypical squamous cells of undetermined significance-low-grade squamous intraepithelial Lesion Triage Study (ALTS) cohort followed up at the clinical center at Birmingham, Alabama. The Cox proportional hazard model with the Wei-Lin-Weisfeld (WLW) approach was used, controlling for relevant covariates. ResultsWomen who were polymorphic for CYP1A1 experienced an HR-HPV clearance rate that was 20% (HR=0.80, p=0.04) lower than women without the polymorphism for CYP1A1, adjusting for all other cofactors. The GSTM1 null genotype was associated with higher HR-HPV clearance rate (HR=1.39, p=0.006). The polymorphism in GSTT1 was not significantly associated with time to clearance of HR-HPV. ConclusionsXenobiotic metabolism genes may influence the natural history of HR-HPV infection and its progression to cervical cancer.

Adherence and retention in clinical trials: A community‐based approach

The Community Health Advisor (CHA) model has been widely used to recruit rural and low-income, mostly African American women into clinical and behavioral research studies. However, little is known about its effectiveness in promoting retention and adherence of such women in clinical trials. The Community-Based Retention Intervention Study evaluated the effectiveness of a community-based intervention strategy using the CHA model and the empowerment theory to improve the retention and adherence of minority and low-income women in clinical trials. The research strategy included the training and use of the volunteer CHAs as research partners. The target population included women participating in the University of Alabama at Birmingham clinical site of the Atypical Squamous Cells of Undetermined Significance-Low-Grade Squamous Intraepithelial Lesion (ASCUS-LSIL) Triage Study (ALTS), a multicenter, randomized clinical trial. Two communities in Jefferson County, Alabama, that were matched according to population demographics were identified and randomly assigned to either an intervention group or a control group. Thirty community volunteers were recruited to be CHAs and to implement the intervention with the ALTS trial participants. In total, 632 ALTS participants agreed to participate in the project, including 359 in the intervention group, which received CHA care, and 273 in the control group, which received standard care. Adherence rates for scheduled clinic visits were significantly higher in the intervention group (80%) compared with the control group (65%; P < .0001). The results indicate that volunteer CHAs can be trained to serve as research partners and can be effective in improving the retention and adherence of minority and low-income women in clinical trials.

Seroprevalence of 8 Oncogenic Human Papillomavirus Genotypes and Acquired Immunity Against Reinfection

Natural human papillomavirus (HPV) antibody titers have shown protection against subsequent HPV infection, but previous studies were restricted to few HPV genotypes. We examined the association of naturally occurring antibodies against 8 carcinogenic HPV types with subsequent infections. A total of 2302 women enrolled in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study provided blood samples at baseline. Serum samples were tested for antibodies against 8 carcinogenic HPV genotypes (16, 18, 31, 33, 35, 45, 52, and 58) using a multiplex serology assay. We analyzed the relationship between HPV antibodies and HPV infection during 2 years of follow-up among women negative for the specific HPV type at baseline. Baseline seroprevalence for HPV16 L1 was associated with decreased risk of DNA positivity for HPV16 (odds ratio, 0.39 [95% confidence interval, .18-.86]) at ≥2 follow-up visits. We observed similar but nonsignificant decreased risks for HPV18 and 31. These findings were restricted to women reporting a new sex partner during follow-up. There was no association between baseline seroprevalence and detection of precancer during follow-up. Seroprevalence conferred protection against subsequent HPV infection for HPV16 and indicated possible protection for 2 other genotypes, suggesting that this effect is common to several HPV genotypes.

Natural immune responses against eight oncogenic human papillomaviruses in the ASCUS-LSIL Triage Study

Only a subset of women with human papillomavirus (HPV) infections will become seropositive, and the factors influencing seroconversion are not well understood. We used a multiplex serology assay in women with mildly abnormal cytology results to examine seroreactivity to oncogenic HPV genotypes. An unbiased subset of women in the atypical squamous cell of undetermined significance /low-grade squamous intraepithelial lesion Triage Study provided blood samples at trial enrollment for serological testing. A Luminex assay based on glutathione s-transferase-L1 fusion proteins as antigens was used to test seroreactivity against eight carcinogenic HPV genotypes (16, 18, 31, 33, 35, 45, 52 and 58). We analyzed the relationship between seroprevalence in women free of precancer (N = 2,464) and HPV DNA status, age, sexual behavior and other HPV-related risk factors. The overall seroprevalence was 24.5% for HPV16 L1 and ∼20% for 18L1 and 31L1. Among women free of precancer, seroprevalence peaked in women less than 29 years and decreased with age. Type-specific seroprevalence was associated with baseline DNA detection for HPV16 (OR = 1.36, 95%CI: 1.04-1.79) and HPV18 (OR = 2.31, 95%CI: 1.61-3.32), as well as for HPV52 and HPV58. Correlates of sexual exposure were associated with increased seroprevalence across most genotypes. Women who were current or former smokers were less likely to be seropositive for all eight of the tested oncogenic genotypes. The multiplex assay showed associations between seroprevalence and known risk factors for HPV infection across nearly all tested HPV genotypes but associations between DNA- and serostatus were weak, suggesting possible misclassification of the participants' HPV serostatus.

A Descriptive Analysis of Prevalent vs Incident Cervical Intraepithelial Neoplasia Grade 3 Following Minor Cytologic Abnormalities

Cervical intraepithelial neoplasia grade 3 (CIN 3) is the best proxy in research and screening for invasive cancer risk. Yet the timing of CIN 3 development is uncertain because of measurement errors integral to its diagnosis. We were interested in estimating the proportions of prevalent vs incident CIN 3 within 2 years of finding a minor cytologic abnormality. We estimate that only 17 (2.8%) of 613 CIN 3 cases diagnosed during the 2-year duration of the atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL) triage study (ALTS) were incident CIN 3 following an incident human papillomavirus (HPV) infection that persisted until the CIN 3 diagnosis was made. Using prevalent high-grade cytology as a marker of prevalent CIN 3, we estimated that another approximately 23% of CIN 3 cases were incident CIN 3 following a prevalently detected HPV infection that persisted until the CIN 3 diagnosis was made. We concluded that most CIN 3 cases diagnosed within the 2-year time frame were prevalent cases, and most incident CIN 3 cases followed a prevalently detected HPV infection.

Association of human papillomavirus type 31 variants with risk of cervical intraepithelial neoplasia grades 2–3

Although the lineages of human papillomavirus type 31 (HPV31) variants are recognized, their clinical relevance is unknown. The purpose of our study was to examine risk of cervical intraepithelial neoplasia Grades 2-3 (CIN2/3) by HPV31 variants. Study subjects were women who participated in the atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion Triage Study and who had HPV31 infections detected at one or more visits. They were followed semi-annually over 2 years for detection of HPV DNA and cervical lesion. HPV31 isolates were characterized by DNA sequencing and assigned into 1 of 3 variant lineages. CIN2/3 was histologically confirmed in 127 (27.0%) of the 470 HPV31-positive women, 83 diagnosed at the first HPV31-positive visit and 44 thereafter. The odds ratio for the association of 2-year cumulative risk of CIN2/3 was 1.7 (95% CI: 1.0-2.9) for infections with A variants and 2.2 (95% CI: 1.2-3.9) for infections with B variants as compared to those with C variants. Among women without CIN2/3 at the first HPV31-positive visit, the risk of subsequent CIN2/3 was 2.2-fold greater for those with A variants (95% CI: 1.0-4.8) and 2.0-fold greater for those with B variants (95% CI: 0.9-4.9) as compared to those with C variants. Similar associations were observed when CIN3 was used as the endpoint. The findings from our study help to tag HPV31 variants that differ in risk of CIN2/3 and to explain in part why some HPV31 infections regress spontaneously and others lead to disease progression.

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Viral Load in the Natural History of Human Papillomavirus Type 16 Infection: A Nested Case–Control Study

Viral load may influence the course of human papillomavirus type 16 (HPV-16) infection. This case-control study was nested within the 2-year Atypical Squamous Cells of Undetermined Significance and Low-Grade Squamous Intraepithelial Lesion Triage Study, in which women were followed semiannually for HPV and cervical intraepithelial neoplasia (CIN). Case patients (n = 62) were women diagnosed with CIN3 following HPV-16-positive detection at a follow-up visit. HPV-16-positive controls (n = 152) without CIN2 or CIN3 were matched to cases based on the follow-up visit in which viral load was measured. Real-time polymerase chain reaction was used for HPV-16 DNA quantification. The risk of CIN3 increased with increasing HPV-16 DNA load at the follow-up visit (odds ratio, 1.63; 95% confidence interval, 1.33-1.99 per 1 log(10) unit increase); the association was not affected by whether HPV-16 was present at enrollment. When HPV-16 was present at both enrollment and follow-up, viral load remained high among cases (P = .77) but decreased substantially among controls (P = .004). Among women with HPV-16 found initially during follow-up, viral load in the first HPV-16-positive sample was associated with short-term persistence; load was higher in those with infection, compared with those without infection, 1 visit after the initial positivity (P = .001). Viral load of newly detected infections and changes in viral load predict persistence and progression of HPV-16 infections.

Cervical Biopsy Sampling Variability in ALTS

To determine histologic sampling variability among clinical center colposcopists and quality control reviewers in the Atypical Squamous Cells of Undetermined Significance/Low-grade Squamous Intraepithelial Lesion Triage Study. Clinical center colposcopists and quality control reviewers independently indicated need for biopsy, number of biopsies needed, and optimal biopsy location on customized computer software and digitized colposcopic images while examining subjects or monitoring colposcopists in the Atypical Squamous Cells of Undetermined Significance/Low-grade Squamous Intraepithelial Lesion Triage Study. Results were compared using percentages of agreement, κ statistics, McNemar, and paired t tests. Colposcopists and reviewers agreed whether a cervical biopsy was indicated for 2,631 (72.9%) of 3,610 evaluable subjects and 415 (91.6%) of 453 subjects with cervical intraepithelial neoplasia 2 or worse by histologic diagnosis. Only 3 of 41 colposcopists indicated 20% or greater of their biopsy sites to be more than 10 mm from reviewers' recommended sites. The mean of the greatest colposcopist-to-reviewer biopsy site distance was significantly greater than the mean maximum distance between reviewers' biopsy sites (14.9 vs 12.2 mm, p < .0001, respectively). Colposcopists indicated a significantly greater number of biopsy sites compared with consensus of reviewers (p < .0001). When cervical cancer precursors are present in women with minor cytologic abnormalities, most colposcopists obtain a biopsy. However, biopsy site placement can vary considerably. Only a minority of colposcopists sample significantly beyond recommended areas and less biopsy site variability occurs among experts.

Hierarchical Clustering of Human Papilloma Virus Genotype Patterns in the ASCUS-LSIL Triage Study

Anogenital cancers are associated with ∼13 carcinogenic human papilloma virus (HPV) types in a broader group that cause cervical intraepithelial neoplasia (CIN). Multiple concurrent cervical HPV infections are common, which complicates the attribution of HPV types to different grades of CIN. Here we report the analysis of HPV genotype patterns in the atypical squamous cells of undetermined significance-low-grade squamous intraepithelial lesion triage study with the use of unsupervised hierarchical clustering. Women who underwent colposcopy at baseline (n = 2,780) were grouped into 20 disease categories based on histology and cytology. Disease groups and HPV genotypes were clustered with the use of complete linkage. Risk of 2-year cumulative CIN3+, viral load, colposcopic impression, and age were compared between disease groups and major clusters. Hierarchical clustering yielded four major disease clusters: cluster 1 included all CIN3 histology with abnormal cytology; cluster 2 included CIN3 histology with normal cytology and combinations with either CIN2 or high-grade squamous intraepithelial lesion cytology; cluster 3 included older women with normal or low-grade histology/cytology and low viral load; and cluster 4 included younger women with low-grade histology/cytology, multiple infections, and the highest viral load. Three major groups of HPV genotypes were identified: group 1 included only HPV16; group 2 included nine carcinogenic types, plus noncarcinogenic HPV53 and HPV66; and group 3 included noncarcinogenic types, plus carcinogenic HPV33 and HPV45. Clustering results suggested that colposcopy missed a prevalent precancer in many women with no biopsy/normal histology and high-grade squamous intraepithelial lesion. This result was confirmed by an elevated 2-year risk of CIN3+ in these groups. Our novel approach to study multiple genotype infections in cervical disease with the use of unsupervised hierarchical clustering can address complex genotype distributions on a population level.

Comparison of Measurements of Human Papillomavirus Persistence for Postcolposcopic Surveillance for Cervical Precancerous Lesions

Following guidelines, women evaluated by colposcopy, but not found to have a precancerous lesion, could be tested again at 12 months for carcinogenic human papillomavirus (HPV). Compared with pooled-probe testing, measuring HPV genotype-specific persistence might better predict subsequent grade 3 cervical intraepithelial neoplasia (CIN3). For women enrolled in the immediate colposcopy arm of the Atypical squamous cells of undetermined significance (ASCUS) and Low-grade squamous intraepithelial lesion (LSIL) Triage Study (ALTS), who underwent enrollment colposcopy but were without prevalently detected CIN2 or worse (CIN2+; n = 671), we compared 1-year HPV persistence, as measured by a pooled HPV genotype test (hybrid capture 2; hc2) versus a research PCR HPV genotyping test (line blot assay; LBA) as predictors of "missed prevalent" or possibly incident CIN3 diagnosed between 12 and 24 months. Thirty-two (4.8%) women were diagnosed with subsequent CIN3. Testing repeatedly hc2-positive (hc2+) was more common (49.0%) than genotype-specific persistence as detected by LBA (30.3%, P < 0.01). Although absolute risks of CIN3 following repeat hc2+ or genotype-specific persistence were similar (8.8% versus 8.4%, P = 0.86), repeat hc2+ was more sensitive for identifying CIN3 than genotype-specific persistence (90.6% versus 53.1%, P < 0.01). Among 329 women repeatedly hc2+, women with persistent HPV16 were at higher risk of CIN3 than non-HPV16-persistent women (23.1% versus 7.0%, P < 0.01). For postcolposcopy management, 1-year HPV persistence as measured by hc2 would recall more women but was more sensitive and similarly predictive for CIN3 in the following year than detection of genotype-specific persistence by LBA. Although find little utility for measuring type-specific persistence, testing for persistent HPV16 might be clinically useful.

Human Papillomavirus Genotypes in Cervical Intraepithelial Neoplasia Grade 3

There are few large case series describing the human papillomavirus (HPV) genotypes found in women diagnosed with rigorously reviewed cervical intraepithelial neoplasia grade 3 (CIN3), cervical precancer. The Atypical Squamous Cells of Undetermined Significance (ASCUS) and Low-Grade Squamous Intraepithelial Lesion (LSIL) Triage Study (ALTS) was a clinical trial to evaluate the best management strategies for women with equivocal (ASCUS) or mildly abnormal (LSIL) Pap tests. During enrollment and the 2-year follow-up, 608 women had a histopathologic diagnosis of CIN3 and PCR-based HPV genotyping results on cervical specimens. The genotyping results were ranked hierarchically according to cancer risk: HPV16 > other carcinogenic HPV > noncarcinogenic HPV > PCR negative. Among the 608 women diagnosed with CIN3, 601 (98.8%) cases were positive for any HPV genotype and 95.4% for any carcinogenic HPV. HPV16 (59.9%), HPV31 (18.1%), HPV52 (14.8%), HPV51 (14.0%), and HPV18 (13.2%) were the five most common HPV genotypes detected. Younger age, consensus histologic confirmation, smoking, and multiparity increased the likelihood of testing HPV 16 positive. Specifically, HPV16-positive CIN3 occurred at a younger age than CIN3 positive for other carcinogenic HPV genotypes (median of 23.5 years versus 25 years, respectively; P = 0.0003, Kruskal-Wallis). HPV16-positive CIN3 was more commonly diagnosed in younger women (versus older women), with consensus diagnosis (versus some disagreement between reviewers), and in smokers (versus nonsmokers), and was less commonly diagnosed in multiparous women compared CIN3 positive for other carcinogenic HPV genotypes. In populations vaccinated against HPV16 (and HPV18), the median age of CIN3 in women with ASCUS and LSIL cytology should shift to older ages, possibly permitting later age at first screening.

Impact of Improved Classification on the Association of Human Papillomavirus With Cervical Precancer

Misclassification of exposure and surrogate endpoints of disease can obscure causal relations. Using data from the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study (ALTS, 1997-2001), the authors explored the impact of exposure (human papillomavirus (HPV) detection) and endpoint (histologic cervical precancer) classification on their mutual association. Women referred into this study with an atypical squamous cells of undetermined significance Papanicolaou test with satisfactory results for all 4 HPV tests were included in this analysis (n = 3,215; 92.2%). HPV testing results were related to different definitions of cervical precancer, based on paired, worst 2-year histologic diagnoses, by calculating clinical sensitivity, specificity, and odds ratios. The authors found that HPV test sensitivity increased and specificity decreased with increasing certainty of cervical precancer, with HPV testing having the highest sensitivity (92%-98%) and lowest specificity (46%-54%) for consensus cervical intraepithelial neoplasia grade 3 (CIN 3). The overall accuracy of each HPV test, as measured by odds ratios, was greatest for consensus CIN-3 diagnoses, from 2- to 4-fold greater than for a less stringent precancer definition of any diagnosis of CIN 2 or more severe. In summary, there was convergence of greater certainty of carcinogenic HPV with greater certainty of a precancerous diagnosis, such that all 4 HPV tests almost always tested positive in women most likely to have cervical precancer. Finding increasingly strong associations when both test and diagnostic misclassification are reduced is a useful sign of "true association" in molecular epidemiology.

Relationship Between Cigarette Smoking and Human Papilloma Virus Types 16 and 18 DNA Load

Although cigarette smoking has been associated with increased human papilloma virus (HPV) detection, its impact on HPV DNA load is unknown. The study subjects were women who were positive for HPV16 and/or HPV18 at enrollment into the Atypical Squamous Cells of Undetermined Significance-Low-grade Squamous Intraepithelial Lesion Triage Study. Assessments of exposure to smoke and sexual behavior were based on self-report. Viral genome copies per nanogram of cellular DNA were measured by multiplex real-time PCR. Linear or logistic regression models were used to assess the relationship between cigarette smoking and baseline viral load. Of the 1,050 women (752 with HPV16, 258 with HPV18, and 40 with both HPV16 and HPV18), 452 (43.0%) were current smokers and 101 (9.6%) were former smokers at enrollment. The baseline viral load was statistically significantly greater for current compared with never smokers (P = 0.03 for HPV16; P = 0.02 for HPV18) but not for former smokers. Among current smokers, neither HPV16 nor HPV18 DNA load seemed to vary appreciably by age at smoking initiation, smoking intensity, or smoking duration. The results remained similar when the analysis of smoking-related HPV16 DNA load was restricted to women without detectable cervical abnormality. Higher baseline HPV16 and HPV18 DNA load was associated with status as a current but not former smoker. A lack of dose-response relationship between cigarette smoking and viral load may indicate a low threshold for the effect of smoking on HPV DNA load.

Effect of the Number of Biopsies on the Subsequent Acquisition of New Human Papillomavirus Infections

To analyze the effect of number of biopsies taken at enrollment with incident human papillomavirus (HPV) infections detected at the next 6-month visit. Using data from the Atypical Squamous Cells of Undetermined Significance (ASCUS) and Low-Grade Squamous Intraepithelial Lesion (LSIL) Triage Study (ALTS), we compared the 6-month acquisition of new HPV infections among 988 women who underwent colposcopy, were not diagnosed and treated for cervical intraepithelial neoplasia grade 2 or more severe lesions, and had polymerase chain reaction results for 38 HPV genotypes at enrollment and follow-up. Our analysis considered each woman's possible acquisition of each of these HPV genotypes. The average 6-month acquisition of any HPV genotype for women with zero, one, and two or more biopsies was 1.82%, 1.74%, and 1.97%, respectively (Ptrend=.7). In a logistic regression model that controlled for age, baseline HPV status, and having a new sexual partner during the 6-month follow-up, two or more biopsies (compared with one biopsy) was not associated with acquiring HPV (odds ratio 1.0, 95% confidence interval 0.75-1.3). Multiple biopsies compared with a single biopsy did not increase the likelihood of acquiring new HPV infections. II.

Human Papillomavirus Types 16 and 18 DNA Load in Relation to Coexistence of Other Types, Particularly Those in the Same Species

Infection with multiple human papillomavirus (HPV) types is common. However, it is unknown whether viral DNA load is related to the coexistence of other types. Study subjects were 802 and 303 women who were positive for HPV16 and HPV18, respectively, at enrollment into the Atypical Squamous Cells of Undetermined Significance and Low-Grade Squamous Intraepithelial Lesion Triage Study. HPV16 and HPV18 E7 copies per nanogram of cellular DNA in cervical swab samples were measured by real-time PCR in triplicate. Concurrent coinfection was common in this population of women with minor cervical lesions; multiple HPV types were detected in 573 (71.4%) of 802 HPV16-positive women and 227 (74.9%) of 303 HPV18-positive women. The adjusted odds ratio associating coinfection with per 1 log unit increase in HPV16 DNA load was 0.78 (95% confidence interval, 0.68-0.89); it was 0.64 (95% confidence interval, 0.52-0.79) for a similar analysis of HPV18 DNA load. Women with, compared with without, coinfection of A9 species types possessed a significantly lower HPV16 DNA load (P < 0.001), whereas women with, compared with without, coinfection of A7 species types possessed a significantly lower HPV18 DNA load (P = 0.001). A trend of decrease in HPV16 DNA load with increasing number of the coexisting non-HPV16 A9 species types was statistically significant (P(trend) = 0.001). Coinfection with other types was associated with lower HPV16 and HPV18 DNA load. The extent of reduction was correlated to phylogenetic distance of the coexisting types to HPV16 and HPV18, respectively.

A Study of Amplicor Human Papillomavirus DNA Detection in the Atypical Squamous Cells of Undetermined Significance–Low-Grade Squamous Intraepithelial Lesion Triage Study

We analyzed the performance of Amplicor for detecting carcinogenic human papillomavirus (HPV) infections and cervical precancer in women with an atypical squamous cells of undetermined significance (ASCUS) Pap and compared the results with Hybrid Capture 2 (hc2) in the ASCUS and low-grade squamous intraepithelial lesion (LSIL) triage study (ALTS). Baseline specimens collected from women referred into ALTS based on an ASCUS Pap result were prospectively tested by hc2 and retrospectively tested by Amplicor (n = 3,277). Following receiver-operator-characteristics curve analysis, Amplicor performance was analyzed at three cutoffs (0.2, 1.0, and 1.5). Paired Amplicor and hc2 results were compared for the detection of 2-year cumulative cervical intraepithelial neoplasia (CIN) grade 3 and more severe disease outcomes (CIN3+) and for the detection of 13 targeted carcinogenic HPV types. Amplicor at the 0.2 cutoff had a higher sensitivity for the detection of CIN3+ (95.8% versus 92.6%, P = 0.01) but a much lower specificity (38.9% versus 50.6%, P < 0.001) than hc2. Amplicor at the 1.5 cutoff had an identical sensitivity for the detection of CIN3+ (92.6%) and a slightly lower specificity (47.5%; P < 0.001). The positive predictive value of hc2 was higher at all Amplicor cutoffs, whereas referral rates were significantly lower (53.2% for hc2 versus 64.1% at the 0.2 cutoff and 56.0% at the 1.5 cutoff, P < 0.001). Amplicor was more analytically specific for detecting targeted carcinogenic HPV types than hc2. Amplicor at the 1.5 cutoff had comparable performance with hc2. Whereas Amplicor missed more disease related to nontargeted types, hc2 was more likely to miss disease related to targeted types.