Methylation of HPV18, HPV31, and HPV45 genomes and cervical intraepithelial neoplasia grade 3

BACKGROUND

Persistent infections with carcinogenic human papillomavirus (HPV) types are the necessary cause of cervical cancer. We recently demonstrated that the HPV16 genome is strongly methylated in cervical precancer compared with transient infections. However, the extent of methylation in other HPV types and its role in progression to cancer is poorly understood.

METHODS

We analyzed whole-genome methylation patterns of the three next most carcinogenic HPV genotypes: HPV31 (closely related to HPV16), and two other closely related types, HPV18 and HPV45. DNA was extracted from cervical cytology specimens from 92 women with precancer and 96 women infected with HPV31, HPV18, or HPV45, but who had no cytological or histological abnormalities. After bisulfite modification, genome-wide pyrosequencing was performed covering 80-106 sites. We calculated differences in median methylation, odds ratios, areas under the curve, and Spearman rank correlation coefficients for methylation levels between different sites. All statistical tests were two-sided.

RESULTS

For all three HPV types, we observed strongly elevated methylation levels at multiple CpG sites in the E2, L2, and L1 regions among women with cervical intraepithelial neoplasia grade 3 compared with women with transient infections. We observed high correlation of methylation patterns between phylogenetically related types. The highest areas under the curve were 0.81 for HPV31, 0.85 for HPV18, and 0.98 for HPV45. Differential methylation patterns in cervical intraepithelial neoplasia grade 3 patients with multiple infections suggest that methylation can clarify which of the infections is causal.

CONCLUSIONS

Carcinogenic HPV DNA methylation indicates transforming HPV infections. Our findings show that methylation of carcinogenic HPV types is a general phenomenon that warrants development of diagnostic assays.

Low risk of type-specific carcinogenic HPV re-appearance with subsequent cervical intraepithelial neoplasia grade 2/3

Carcinogenic human papillomavirus (HPV) infections are very common after sexual debut and nearly all become undetectable ("clear") within a few years. Following clearance, the long-term risks of type-specific HPV re-appearance and subsequent risk of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) are not well defined. In the 7-year, population-based cohort study in Guanacaste, Costa Rica, we studied how often type-specific carcinogenic HPV infections re-appeared after clearance and how often re-appearance led to CIN2+. We considered 1,740 carcinogenic HPV infections detected by MY09/11 PCR among 2,805 women (18-91 years old, median 34) who were actively followed at 6- or 12-month intervals. We identified women with one or more type-specific HPV infections that cleared and re-appeared and further defined a subgroup of "definite clearance and re-appearance" (≥2 intervening negative results over a period of ≥1 year). We determined the absolute risk of CIN2+ among the different groups. p values are two-sided. Only 7.7% (81/1,052) of HPV-infected women had intervening negative results. Very few (3.7%, 39/1,052) had "definite clearance and re-appearance", of which 5.1% (2/39) subsequently persisted to a diagnosis of CIN2. There were zero CIN3+ lesions. Extremely few women (2/2,805 of women in our cohort) had a type-specific carcinogenic HPV infection clear, re-appear and lead to CIN2+. If confirmed, this argues against vaccination to avoid re-appearance that leads to precursor lesions and against the need of frequent HPV screening after initial negative results.

Human papillomavirus DNA methylation as a potential biomarker for cervical cancer

Sexually transmitted carcinogenic human papillomavirus (HPV) infections are extraordinarily prevalent worldwide. However, most incident HPV infections clear within a few years, whereas a small minority persists to invasive cancer. Recent studies indicate that detection of methylated viral DNA may distinguish women with cervical intraepithelial neoplasia grade 2+ (CIN2+) from those with a carcinogenic HPV-type infection that shows no evidence of CIN2+. Several studies have reported a positive association between methylation of CpG sites in the L1 gene and CIN2+, although there are inconclusive results about methylation of CpG sites in the upstream regulatory region (URR). In this review, we summarize the current state of knowledge on HPV DNA methylation in cervical carcinogenesis, and discuss the merits of different methods used to measure HPV DNA methylation. To follow the promising leads, we suggest future studies to validate the use of methylated carcinogenic HPV DNA as a predictive and/or diagnostic biomarker for risk of cervical cancer among HPV-positive women.

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.

Prevalence of and risk factors for anal human papillomavirus infection among young healthy women in Costa Rica

BACKGROUND

Anal cancer is caused by human papillomavirus (HPV), yet little is known about anal HPV infection among healthy young women.

METHODS

A total of 2017 sexually active women in the control arm of an HPV-16/18 vaccine trial had a single anal specimen collected by a clinician at the 4-year study visit. Samples were tested for HPV by SPF(10) PCR/DEIA/LiPA(25), version 1.

RESULTS

A total of 4% of women had HPV-16, 22% had oncogenic HPV, and 31% had any HPV detected in an anal specimen. The prevalence of anal HPV was higher among women who reported anal intercourse, compared with those who did not (43.4% vs 28.4%; P< .001). Among women who reported anal intercourse, cervical HPV (adjusted odds ratio [aOR], 5.3 [95% confidence interval {CI}, 3.4-8.2]), number of sex partners (aOR, 2.2 [95% CI, 1.1-4.6] for ≥ 4 partners), and number of anal intercourse partners (aOR, 1.9 [95% CI, 1.1-3.3] for ≥ 2 partners) were independent risk factors for anal HPV detection. Among women who reported no anal intercourse, cervical HPV (aOR, 4.7 [95% CI, 3.7-5.9]), number of sex partners (aOR, 2.4 [95% CI, 1.7-3.4] for ≥ 4 partners), and report of anal fissures (aOR, 2.3 [95% CI, 1.1-4.8]) were associated with an increased odds of anal HPV detection.

CONCLUSION

Anal HPV is common among young women, even those who report no anal sex, and was associated with cervical HPV infection. Anal fissures in women who report never having had anal intercourse may facilitate HPV exposure.

CLINICAL TRIALS REGISTRATION

NCT00128661.

Persistence of newly detected human papillomavirus type 31 infection, stratified by variant lineage

Variants of human papillomavirus (HPV) type 31 have been shown to be related both to risk of cervical lesions and racial composition of a population. It is largely undetermined whether variants differ in their likelihood of persistence. Study subjects were women who participated in the ASCUS-LSIL Triage Study and who had a newly detected HPV31 infection during a two-year follow-up with six-month intervals. HPV31 isolates were characterized by sequencing and assigned to one of three variant lineages. Loss of the newly detected HPV31 infection was detected in 76 (47.5%) of the 160 women (32/67 with A variants, 16/27 with B variants and 28/66 with C variants). The adjusted hazard ratio associating loss of the infection was 1.2 (95% CI, 0.7-2.1) for women with A variants and 2.1 (95% CI, 1.2-3.5) for women with B variants when compared with those with C variants. Infections with A and C variants were detected in 50 and 41 Caucasian women and in 15 and 23 African-American women, respectively. The likelihood of clearance of the infection was significantly lower in African-American women with C variants than in African-American women with A variants (p = 0.05). There was no difference in the likelihood of clearance between A and C variants among Caucasian women. Our data indicated that infections with B variants were more likely to resolve than those with C variants. The difference in clearance of A vs. C variants in African-Americans, but not in Caucasians, suggests a possibility of the race-related influence in retaining the variant-specific infection.

The cervical microbiome over 7 years and a comparison of methodologies for its characterization

BACKGROUND

The rapidly expanding field of microbiome studies offers investigators a large choice of methods for each step in the process of determining the microorganisms in a sample. The human cervicovaginal microbiome affects female reproductive health, susceptibility to and natural history of many sexually transmitted infections, including human papillomavirus (HPV). At present, long-term behavior of the cervical microbiome in early sexual life is poorly understood.

METHODS

The V6 and V6-V9 regions of the 16S ribosomal RNA gene were amplified from DNA isolated from exfoliated cervical cells. Specimens from 10 women participating in the Natural History Study of HPV in Guanacaste, Costa Rica were sampled successively over a period of 5-7 years. We sequenced amplicons using 3 different platforms (Sanger, Roche 454, and Illumina HiSeq 2000) and analyzed sequences using pipelines based on 3 different classification algorithms (usearch, RDP Classifier, and pplacer).

RESULTS

Usearch and pplacer provided consistent microbiome classifications for all sequencing methods, whereas RDP Classifier deviated significantly when characterizing Illumina reads. Comparing across sequencing platforms indicated 7%-41% of the reads were reclassified, while comparing across software pipelines reclassified up to 32% of the reads. Variability in classification was shown not to be due to a difference in read lengths. Six cervical microbiome community types were observed and are characterized by a predominance of either G. vaginalis or Lactobacillus spp. Over the 5-7 year period, subjects displayed fluctuation between community types. A PERMANOVA analysis on pairwise Kantorovich-Rubinstein distances between the microbiota of all samples yielded an F-test ratio of 2.86 (p<0.01), indicating a significant difference comparing within and between subjects' microbiota.

CONCLUSIONS

Amplification and sequencing methods affected the characterization of the microbiome more than classification algorithms. Pplacer and usearch performed consistently with all sequencing methods. The analyses identified 6 community types consistent with those previously reported. The long-term behavior of the cervical microbiome indicated that fluctuations were subject dependent.

Direct comparison of HPV16 serological assays used to define HPV-naïve women in HPV vaccine trials

BACKGROUND

Two HPV serological assays, the competitive Luminex immunoassay (cLIA), and an enzyme-linked immunoassay (ELISA) against HPV16 have been used to define HPV-naïve subcohorts within large HPV vaccination trials. Some of the variation in estimated vaccine efficacies may be due to the differences in these assays used to define the HPV-naïve subgroups. To guide the interpretation of published results, we compared these assays.

METHODS

Replicate enrollment sera from a stratified sample of 388 unvaccinated women from the control arm of the Costa Rica HPV 16/18 Vaccine Trial were measured for antibodies against HPV16 using cLIA and ELISA. Agreement between the assays was estimated using standard and alternative assay cutoffs.

RESULTS

Using laboratory-determined seropositivity cutoffs, sampling-adjusted HPV16 seropositivity was 24.8% by ELISA and 7.2% by cLIA. Comparing cLIA and ELISA antibody levels based on the standard cutoffs, overall agreement was 53% (positive-agreement = 49%). The poor agreement was mainly driven by the higher sensitivity of the ELISA than cLIA, resulting in 30% of the ELISA-positive sample that were cLIA-negative (none of the ELISA-negatives were cLIA-positive). Increasing ELISA cutoff to 54 ELISA units (EU)/mL (the level which maximized agreement with cLIA; ELISA standard cutoff is 8 EU/mL) resulted in higher agreement (overall agreement = 91%; positive agreement = 78%).

CONCLUSIONS

ELISA and cLIA are different from each other based on the laboratory-determined cutoff. Increasing ELISA cutoff increased agreement with cLIA, which could facilitate comparisons among studies that use different assays.

IMPACT

Keeping cLIA at the laboratory-determined cutoff but altering ELISA cutoff for seropositivity might facilitate vaccine efficacy comparisons in the naïve cohorts defined by cLIA.

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from six working groups, and a recent symposium co-sponsored by the ACS, American Society for Colposcopy and Cervical Pathology (ASCCP), and American Society for Clinical Pathology (ASCP), which was attended by 25 organizations. The new screening recommendations address age-appropriate screening strategies, including the use of cytology and high-risk human papillomavirus (HPV) testing, follow-up (e.g., management of screen positives and screening interval for screen negatives) of women after screening, age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16/18 infections.

Performance of p16/Ki-67 immunostaining to detect cervical cancer precursors in a colposcopy referral population

PURPOSE

Cytology-based screening has limited sensitivity to detect prevalent cervical precancers. Human papilloma virus (HPV) DNA testing is highly sensitive and provides a high, long-term reassurance of low risk of cervical cancer. However, the specificity of HPV DNA testing is limited, requiring additional, more disease-specific markers for efficient screening approaches.

EXPERIMENTAL DESIGN

Liquid-based cytology samples were collected from 625 women referred to colposcopy. A slide was stained using the CINtec plus cytology assay. Pap cytology and HPV genotyping were conducted from the same vial. Clinical performance characteristics were calculated for all women, stratified by age, and for women referred with a low-grade squamous intraepithelial lesion (LSIL) Pap.

RESULTS

p16/Ki-67 positivity increased with histologic severity, from 26.8% in normal histology, 46.5% in CIN1, 82.8% in CIN2 to 92.8% in CIN3. Among women with CIN3, p16/Ki-67 positivity increased from 77.8% for women younger than 30 years without HPV16 to 100% for women 30 years and older with HPV16. The sensitivity and specificity to detect CIN3+ were 93.2% and 46.1%, respectively, and increased to 97.2% and 60.0% among women 30 years and older. In women with high-risk (HR)-HPV-positive atypical squamous cells of undetermined significance (ASC-US) and LSIL, sensitivity and specificity for detection of CIN3 were 90.6% and 48.6%, respectively.

CONCLUSIONS

p16/Ki-67 testing could reduce referral to colposcopy by almost half while detecting the most severe cases of CIN3. The high sensitivity of p16/Ki-67 with significantly improved specificity compared with HPV testing makes p16/Ki-67 a viable option for LSIL triage. Further studies are required to evaluate p16/Ki-67 as triage marker in HPV-based screening strategies.

The age-specific prevalence of human papillomavirus and risk of cytologic abnormalities in rural Nigeria: implications for screen-and-treat strategies

Cervical screening for carcinogenic human papillomavirus (HPV) infection is being considered for low-income countries. Effectiveness requires targeted screening in older women in whom prevalent infections are more likely to be persistent and predictive of precancer. Some studies in West Africa have found unusually high HPV prevalences across all adult ages, which may reduce the positive predictive value (PPV) of HPV-based screening, if positivity in older women does not sufficiently predict elevated risk. We conducted a population-based study in rural Nigeria to identify HPV prevalence and associated cervical abnormalities. Using stratified random sampling, we enrolled women age 15+. Nonvirgins had a cervical exam including liquid-based cytology and PCR HPV DNA testing from residual cytology specimens. Two-thirds of invited women participated, and 14.7% had detectable carcinogenic HPV, a proportion that did not decline with age (p-trend = 0.36) and showed slight peaks in the 15-29 and 60-69 age groups. Among women of the age typically considered for screen-and-treat programs (30-49 years), 12.8% were HPV positive, and the PPV for high-grade or worse cytology was 16.4%. Comparatively, women age < 30 were more likely to be HPV positive (18.9%, p = 0.03) with a lower PPV (4.2% p = 0.05). Among women age 50+ (typically excluded from screening in resource-poor settings because inexpensive treatment is not available), HPV positivity was 14.2% with a PPV of 13.9%. In Irun and similar settings where HPV does not decline with age, HPV-based screen-and-treat programs might be feasible for mid-adult women because prevalence is sufficiently low and positivity predicts elevated risk of more easily treated precancer.

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from 6 working groups, and a recent symposium cosponsored by the ACS, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology, which was attended by 25 organizations. The new screening recommendations address age-appropriate screening strategies, including the use of cytology and high-risk human papillomavirus (HPV) testing, follow-up (eg, the management of screen positives and screening intervals for screen negatives) of women after screening, the age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16 and HPV18 infections.

Heterogeneity of high-grade cervical intraepithelial neoplasia related to HPV16: implications for natural history and management

Factors associated with progression from cervical intraepithelial neoplasia (CIN) grades 2 and 3 to invasive cancer are not well understood; most CIN2 and CIN3 do not progress to cancer. Among carcinogenic human papillomavirus (HPV) types, infections with HPV16 have the highest risk of progressing to cancer. We evaluated the heterogeneity of risk factors, lesion size, colposcopic impression and colposcopic biopsy results in relation to HPV16 status among 627 women with CIN2 or CIN3 in women referred to colposcopy at the University of Oklahoma. Loop excision specimens were evaluated in 12 radial segments to estimate lesion size. The mean age at CIN3 was 27.7 years for HPV16-positive women (n = 225) and 33.6 years for HPV16-negative women (n = 104). The average lesion size did not differ by HPV16 status (p = 0.83). Among HPV16-positive women with CIN3, lesions were significantly larger in women 30 years and older (p = 0.03). Colposcopic impression was worse in women with HPV16 infections (p = 0.009), but the detection of CIN3 at the preceding biopsy was not improved in HPV16-positive women. CIN3 is detected at the same lesion size, but at much younger age in women with HPV16 infections, suggesting faster growth. CIN2 lesion size in women without HPV16 peaks below 30 years and then decreases, suggesting frequent regression, whereas HPV16-related CIN2 is more likely to persist. Lesion size seems to be an important determinant of colposcopy and biopsy performance. Genotyping for HPV16 in cervical cancer screening can improve risk stratification but may pose challenges to finding small lesions in colposcopy.

Effectiveness of a simple rapid human papillomavirus DNA test in rural Nigeria

Success of the new human papillomavirus (HPV) DNA test for low-resource settings (careHPV™ test; QIAGEN Gaithersburg Inc., Gaithersburg, MD) requires good test performance when operated by personnel with limited laboratory experience. We evaluated the transferability, reliability, and accuracy of the careHPV test nested within a cervical screening project in a large Nigerian village. CareHPV testing was performed on screen-positive (n = 345) and screen-negative (n = 42) women attending colposcopy (68.3% of referred). Biopsies of abnormal-appearing areas were processed and read in the U.S. CareHPV specimens taken immediately before colposcopy were processed up to four times (in the field) by two secondary school graduates without laboratory experience, trained for this study. Specifically, QIAGEN Gaithersburg trained a laboratory-inexperienced U.S. researcher, who trained the first local technician who, in turn, trained the second. Residual specimens were sent to the U.S. for MY09/MY11 PCR testing for 13 carcinogenic genotypes (HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68) plus HPV66 (included in careHPV). Intrarater agreement was 98.8% (κ = 0.97) and 98.9% (κ = 0.97) for Technicians 1 and 2, respectively, while inter-rater agreement was 96.3% (κ = 0.90). Agreement with MY09/MY11 PCR (virologic reference standard) was 89.3% (κ = 0.73) with 74.2% sensitivity and 95.7% specificity. The careHPV test detected 12 (80%) of 15 histologically confirmed cervical intraepithelial neoplasia Grade 2 (CIN2) or worse lesions, with an estimated 83.0% specificity to detect <CIN2. In a challenging low-resource setting with minimal intervention, the careHPV test performed adequately with high specificity but possibly lower sensitivity than HPV DNA tests currently used in controlled situations.

Molecular mapping of high-grade cervical intraepithelial neoplasia shows etiological dominance of HPV16

Women with high-grade cervical intraepithelial neoplasia (HGCIN) frequently present with multiple cervical lesions and multiple concomitant Human papillomavirus (HPV) genotype infections. To elucidate HPV genotype attribution in different regions on the cervix, we performed molecular mapping of cervical disease in women with HGCIN. Thirteen subjects referred to colposcopy for abnormal cervical cancer screening results were included. A cervical smear and biopsies from 4 different areas on the cervix were collected. HPV genotyping using Linear Array (for cytology) or SPF(10) LiPA(25) (for histology) were performed in 13 smears, 52 whole sections from biopsies and 138 tissue regions isolated with laser capture microdissection (LCM). Twelve subjects had a diagnosis of CIN3 and one subject had a diagnosis of CIN2 based on the worst histology found in 4 biopsies. Eight of the 13 smears (62%) showed multiple genotype infections. Four of 13 women (31%) had multiple HPV infections in their biopsies. After performing LCM-PCR, only one woman (8%) had two different carcinogenic HPV types in morphologically distinct, but colliding HGCIN lesions. HPV16 was identified as the causal type in all women with HPV16 in cytology. A large proportion of other HPV types found in cervical smears were not detected at the tissue level. Using tissue-based genotyping and LCM-PCR analysis, we were able to attribute an individual HPV type to each area of CIN lesions. We demonstrate that HPV16 is even more etiologically dominant than previously thought, based on various genotype attribution models.

Single nucleotide polymorphisms in the PRDX3 and RPS19 and risk of HPV persistence and cervical precancer/cancer

Background

Host genetic factors might affect the risk of progression from infection with carcinogenic human papillomavirus (HPV), the etiologic agent for cervical cancer, to persistent HPV infection, and hence to cervical precancer and cancer.

Methodology/Principal Findings

We assessed 18,310 tag single nucleotide polymorphisms (SNPs) from 1113 genes in 416 cervical intraepithelial neoplasia 3 (CIN3)/cancer cases, 356 women with persistent carcinogenic HPV infection (median persistence of 25 months) and 425 randomly selected women (non-cases and non-HPV persistent) from the 10,049 women from the Guanacaste, Costa Rica HPV natural history cohort. For gene and SNP associations, we computed age-adjusted odds ratio and p-trend. Three comparisons were made: 1) association with CIN3/cancer (compared CIN3/cancer cases to random controls), 2) association with persistence (compared HPV persistence to random controls), and 3) progression (compared CIN3/cancers with HPV-persistent group). Regions statistically significantly associated with CIN3/cancer included genes for peroxiredoxin 3 PRDX3, and ribosomal protein S19 RPS19. The single most significant SNPs from each gene associated with CIN3/cancer were PRDX3 rs7082598 (P_trend<0.0001), and RPS19 rs2305809 (P_trend=0.0007), respectively. Both SNPs were also associated with progression.

Conclusions/Significance

These data suggest involvement of two genes, RSP19 and PRDX3, or other SNPs in linkage disequilibrium, with cervical cancer risk. Further investigation showed that they may be involved in both the persistence and progression transition stages. Our results require replication but, if true, suggest a role for ribosomal dysfunction, mitochondrial processes, and/or oxidative stress, or other unknown function of these genes in cervical carcinogenesis.

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from 6 working groups, and a recent symposium cosponsored by the ACS, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology, which was attended by 25 organizations. The new screening recommendations address age-appropriate screening strategies, including the use of cytology and high-risk human papillomavirus (HPV) testing, follow-up (eg, the management of screen positives and screening intervals for screen negatives) of women after screening, the age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16 and HPV18 infections.

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.

Methylation of human papillomavirus type 16 genome and risk of cervical precancer in a Costa Rican population

BACKGROUND

Previous studies have suggested an association between human papillomavirus type 16 (HPV16) genome methylation and cervical intraepithelial neoplasia grade 3 (CIN3) (ie, cervical precancer) and cancer, but the results have been inconsistent.

METHODS

We designed a case-control study within a large prospective cohort of women who underwent multiple screenings for cervical cancer in Guanacaste, Costa Rica. Diagnostic specimens were collected at the time of CIN3 diagnosis (n = 30 case subjects) and persistent HPV16 infection (persistence; n = 35 case subjects), prediagnostic specimens at the first HPV16-positive screening visit (n = 20 CIN3 case subjects; n = 35 persistence case subjects), and control specimens from women with infection clearance within 2 years (n = 34 control subjects). DNA extracted from specimens (cervical cells) was analyzed for methylation levels at 67 CpG sites throughout the HPV16 genome using pyrosequencing. Benjamini-Hochberg method was used to account for multiple testing. Associations between methylation levels and risk of CIN3 or persistence were assessed using logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Increased methylation in diagnostic vs control specimens at nine CpG sites, three in each L1, L2, and E2/E4 genomic regions, was associated with an increased risk of CIN3 (third tertile [high] vs first and second tertiles combined [low], OR = 3.29 [95% CI = 1.16 to 9.34] to 11.12 [95% CI = 2.29 to 76.80]) and persistence. High methylation at three of these CpG sites was associated with a much higher risk when combined compared with low methylation at these sites (OR = 52, 95% CI = 4.0 to 670). In prediagnostic vs control specimens, increased methylation at a CpG site (nucleotide position 4261) in L2 was associated with an increased risk of CIN3.

CONCLUSION

In this HPV16-infected cohort, increased methylation of CpG sites within the HPV16 genome before diagnosis and at the time of diagnosis was associated with cervical precancer.

A large, population-based study of age-related associations between vaginal pH and human papillomavirus infection

Background

Vaginal pH is related to genital tract inflammation and changes in the bacterial flora, both suggested cofactors for persistence of human papillomavirus (HPV) infection. To evaluate the relationship between vaginal pH and HPV, we analyzed data from our large population-based study in Guanacaste, Costa Rica. We examined vaginal pH and the risk of HPV infection, cytological abnormalities, and C. trachomatis infection.

Methods

Our study included 9,165 women aged 18-97 at enrollment with a total of 28,915 visits (mean length of follow-up = 3.4 years). Generalized estimating equations were used to evaluate the relationship between vaginal pH and HPV infection (both overall and single versus multiple types) and low-grade squamous intraepithelial lesions (LSIL), the cytomorphic manifestation of HPV infection. The relationship between enrollment vaginal pH and C. trachomatis infection was assessed by logistic regression. Results were stratified by age at visit.

Results

Detection of HPV was positively associated with vaginal pH, mainly in women < 35 years (p-trend = 0.009 and 0.007 for women aged < 25 and 25-34 years, respectively). Elevated vaginal pH was associated with 30% greater risk of infection with multiple HPV types and with LSIL, predominantly in women younger than 35 and 65+ years of age. Detection of C. trachomatis DNA was associated with increased vaginal pH in women < 25 years (OR 2.2 95% CI 1.0-5.0).

Conclusions

Our findings suggest a possible association of the cervical microenvironment as a modifier of HPV natural history in the development of cervical precancer and cancer. Future research should include studies of vaginal pH in a more complex assessment of hormonal changes and the cervicovaginal microbiome as they relate to the natural history of cervical neoplasia.

Clinical and pathological heterogeneity of cervical intraepithelial neoplasia grade 3

Objective

Cervical intraepithelial neoplasia grade 3 (CIN3), the immediate cervical cancer precursor, is a target of cervical cancer prevention. However, less than half of CIN3s will progress to cancer. Routine treatment of all CIN3s and the majority of CIN2s may lead to overtreatment of many lesions that would not progress. To improve our understanding of CIN3 natural history, we performed a detailed characterization of CIN3 heterogeneity in a large referral population in the US.

Methods

We examined 309 CIN3 cases in the SUCCEED, a large population-based study of women with abnormal cervical cancer screening results. Histology information for 12 individual loop electrosurgical excision procedure (LEEP) segments was evaluated for each woman. We performed case-case comparisons of CIN3s to analyze determinants of heterogeneity and screening test performance.

Results

CIN3 cases varied substantially by size (1–10 LEEP segments) and by presentation with concomitant CIN2 and CIN1. All grades of CINs were equally distributed over the cervical surface. In half of the women, CIN3 lesions were found as multiple distinct lesions on the cervix. Women with large and solitary CIN3 lesions were more likely to be older, have longer sexual activity span, and have fewer multiple high risk HPV infections. Screening frequency, but not HPV16 positivity, was an important predictor of CIN3 size. Large CIN3 lesions were also characterized by high-grade clinical test results.

Conclusions

We demonstrate substantial heterogeneity in clinical and pathological presentation of CIN3 in a US population. Time since sexual debut and participation in screening were predictors of CIN3 size. We did not observe a preferential site of CIN3 on the cervical surface that could serve as a target for cervical biopsy. Cervical cancer screening procedures were more likely to detect larger CIN3s, suggesting that CIN3s detected by multiple independent diagnostic tests may represent cases with increased risk of invasion.

Policy implications of adjusting randomized trial data for economic evaluations: a demonstration from the ASCUS-LSIL Triage Study

BACKGROUND

Although the randomized controlled trial (RCT) is widely considered the most reliable method for evaluation of health care interventions, challenges to both internal and external validity exist. Thus, the efficacy of an intervention in a trial setting does not necessarily represent the real-world performance that decision makers seek to inform comparative effectiveness studies and economic evaluations.

METHODS

Using data from the ASCUS-LSIL Triage Study (ALTS), we performed a simplified economic evaluation of age-based management strategies to detect cervical intraepithelial neoplasia grade 3 (CIN3) among women who were referred to the study with low-grade squamous intraepithelial lesions (LSIL). We used data from the trial itself to adjust for 1) potential lead time bias and random error that led to variation in the observed prevalence of CIN3 by study arm and 2) potential ascertainment bias among providers in the most aggressive management arm.

RESULTS

We found that using unadjusted RCT data may result in counterintuitive cost-effectiveness results when random error and/or bias are present. Following adjustment, the rank order of management strategies changed for 2 of the 3 age groups we considered.

CONCLUSIONS

Decision analysts need to examine study design, available trial data, and cost-effectiveness results closely in order to detect evidence of potential bias. Adjustment for random error and bias in RCTs may yield different policy conclusions relative to unadjusted trial data.

Longitudinal analysis of carcinogenic human papillomavirus infection and associated cytologic abnormalities in the Guanacaste natural history study: looking ahead to cotesting

BACKGROUND

Few studies have addressed the timing of cervical cytologic abnormalities and human papillomavirus (HPV) positivity during the course of an infection. It remains largely unknown how infections detected by HPV and cytology wax and wane relative to each other. The aim of this analysis was to assess the longitudinal relationship of abnormal cytology and HPV positivity in a 7-year prospective study of 2500 women in Guanacaste, Costa Rica.

METHODS

At each semiannual or annual visit, cervical specimens were screened using liquid-based cytology and tested for >40 HPV types with use of MY09/MY11 L1 degenerate primer polymerase chain reaction-based methods. On the basis of previous work, we separated prevalent and newly detected infections in younger and older women.

RESULTS

Among newly detected HPV- and/or cytology-positive events, HPV and cytology appeared together ∼60% of the time; when discordant, HPV tended to appear before cytology in younger and older women. Combining newly and prevalently detected events, HPV and cytology disappeared at the same time >70% of the time. When discordant, HPV tended to disappear after cytology in younger and older women.

CONCLUSIONS

Detection of HPV DNA and associated cytological abnormalities tend to come and leave together; however, when discordant, detection of HPV DNA tends to precede and/or last longer than associated cytologic abnormalities.

The clinical meaning of a cervical intraepithelial neoplasia grade 1 biopsy

OBJECTIVE

To determine whether the diagnosis of cervical intraepithelial neoplasia (CIN) grade 1 increases the risk of CIN 3 above what is observed for human papillomavirus (HPV) infection.

METHODS

Using data from the atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesions (LSIL) triage study, we compared the 2-year cumulative risk of CIN 3 for women with an enrollment diagnosis of CIN 1 (n=594) (median age 23 years) compared with those with negative histology or no biopsy taken at colposcopy ("no CIN 1," n=570) (median age 24 years). Baseline cervical specimens were tested for carcinogenic HPV by a clinical HPV test and HPV genotypes by polymerase chain reaction. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) as a measure of association of enrollment status, including CIN 1 compared with no CIN 1 diagnosis, with 2-year worst outcomes of CIN 3.

RESULTS

The two-year risks of CIN 3 were 10.3% (95% CI 7.9-13.0) for women with CIN 1, 7.3% (95% CI 4.6-10.9) for negative histology, and 6.4% (95% CI 3.8-9.9) for women referred to colposcopy and no biopsies were taken (P=.1). The 2-year risks of CIN 3 for women positive for HPV16, HPV18, or other carcinogenic HPV genotypes were 19.1%, 13.9%, and 5.7%, respectively, and did not differ significantly by the baseline cytology interpretation (ASCUS or LSIL). Taking HPV genotypes into account, having a CIN 1 (compared with no CIN 1) was not a risk factor for developing CIN 3 (OR 0.99, 95% CI 0.54-1.8).

CONCLUSION

A CIN 1 diagnosis does not represent a significant risk factor for CIN 3 above the risk attributed to its molecular cause, genotype-specific HPV infection.

LEVEL OF EVIDENCE

II.