DNA methylation in human papillomavirus-infected cervical cells is elevated in high-grade squamous intraepithelial lesions and cancer

Objective

DNA methylation has been shown to be a potential biomarker for early cancer detection. The aim of this study was to evaluate DNA methylation profiles according to liquid-based Pap (LBP) test results and to assess their diagnostic value in a Korean population.

Methods

A total of 205 patients with various Papanicolaou test results were enrolled to this study (negative, 26; atypical squamous cells of undetermined significance, 39; low grade squamous intraepithelial lesion, 44; high grade squamous intraepithelial lesion (HSIL), 48; and cancer, 48). DNA methylation analysis of four genes, ADCYAP1, PAX1, MAL, and CADM1, was performed on residual cervical cells from LBP samples using a quantitative bisulfite pyrosequencing method. To evaluate the diagnostic performance of the four methylated genes for cancer detection, receiver operating characteristic (ROC) curves were drawn. Sensitivities and specificities were also tested at cutoffs determined from the ROC curves.

Results

Cervical cancer cells showed dramatically increased methylation levels for the four genes analyzed. ADCYAP1 and PAX1 also trended toward elevated methylation levels in HSIL samples, although the levels were much lower than those in cancer cells. The sensitivities of methylated ADCYAP1, PAX1, MAL, and CADM1 for the detection of cancer were 79.2%, 75.0%, 70.8%, and 52.1%, and the specificities were 92.0%, 94.0%, 94.7%, and 94.0%, respectively. Methylated ADCYAP1 and PAX1 demonstrated relatively better discriminatory ability than did methylated MAL and CADM1 (area under the curves 0.911 and 0.916 vs. 0.854 and 0.756, respectively).

Conclusion

DNA methylation status, especially in the ADCYAP1 and PAX1 genes, showed relatively good specificity, ranging from 90% to 94%. The possible additive and complementary roles of DNA methylation testing with respect to conventional cervical cancer screening programs will need to be validated in prospective population-based studies.     

Coexisting high-grade glandular and squamous cervical lesions and human papillomavirus infections

The frequency of high-risk human papillomavirus (hr-HPV) genotypes in patients with adenocarcinoma in situ (ACIS) with coexisting cervical intraepithelial neoplasia (CIN), ACIS without coexisting CIN, and high-grade CIN (CIN II/III) was studied, in order to gain more insight into the relation between hr-HPV infections and the development of coexisting squamous and glandular lesions. The SPF(10) LiPA PCR was used to detect simultaneously 25 different HPV genotypes in biopsies obtained from 90 patients with CIN II/III, 47 patients with ACIS without coexisting CIN, and 49 patients with ACIS and coexisting CIN. hr-HPV was detected in 84 patients (93%) with CIN II/III, 38 patients (81%) with ACIS without CIN, and in 47 patients (96%) with ACIS and coexisting CIN. A total of 13 different hr-HPV genotypes were detected in patients with CIN II/III, and only five in patients with ACIS with/without coexisting CIN. HPV 31, multiple hr-HPV genotypes, and HPV genotypes other than 16, 18, and 45 were significantly more often detected in patients with CIN II/III, while HPV 18 was significantly more often detected in patients with ACIS with/without CIN. There were no significant differences in the frequency of specific hr-HPV genotypes between patients with ACIS with or without coexisting CIN. In conclusion, the frequency of specific hr-HPV genotypes is similar for patients with ACIS without CIN and patients with ACIS and coexisting CIN, but is significantly different for patients with CIN II/III without ACIS. These findings suggest that squamous lesions, coexisting with high-grade glandular lesions, are aetiologically different from squamous lesions without coexisting glandular lesions.     

Comparison of HPV type distribution in high-grade cervical lesions and cervical cancer: a meta-analysis

Particular types of human papillomavirus (HPV) infection may preferentially progress from high-grade squamous intraepithelial lesions (HSIL) to squamous cell carcinoma of the cervix (SCC). We performed a meta-analysis of published data to compare HPV type distribution in HSIL and SCC. HPV16, 18 and 45 were each more prevalent in SCC than HSIL, whereas the reverse was true for other oncogenic types including HPV31, 33, 52 and 58. These data suggest that HSILs infected with HPV16, 18 and 45 preferentially progress to SCC. This may have implications for follow-up protocols of future HPV-based cervical cancer screening programmes and for HPV vaccine trials.     

Human papillomavirus type distribution in invasive cervical cancer and high-grade cervical lesions: a meta-analysis update

Data on human papillomavirus (HPV) type distribution in invasive and pre-invasive cervical cancer is essential to predict the future impact of HPV16/18 vaccines and HPV-based screening tests. A meta-analyses of HPV type distribution in invasive cervical cancer (ICC) and high-grade squamous intraepithelial lesions (HSIL) identified a total of 14,595 and 7,094 cases, respectively. In ICC, HPV16 was the most common, and HPV18 the second most common, type in all continents. Combined HPV16/18 prevalence among ICC cases was slightly higher in Europe, North America and Australia (74-77%) than in Africa, Asia and South/Central America (65-70%). The next most common HPV types were the same in each continent, namely HPV31, 33, 35, 45, 52 and 58, although their relative importance differed somewhat by region. HPV18 was significantly more prevalent in adeno/adenosquamous carcinoma than in squamous cell carcinoma, with the reverse being true for HPV16, 31, 33, 52 and 58. Among HSIL cases, HPV16/18 prevalence was 52%. However, HPV 16, 18 and 45 were significantly under-represented, and other high-risk HPV types significantly over-represented in HSIL compared to ICC, suggesting differences in type-specific risks for progression. Data on HPV-typed ICC and HSIL cases were particularly scarce from large regions of Africa and Central Asia.     

宫颈高级别病变与HPV感染型别分析

目的探讨HPV在宫颈高级别病变中的感染率及感染型别。方法采用导流杂交法分别检测CINII～Ⅲ30例和宫颈癌患者160例HPV基因型别,比较HPV感染与宫颈病变的关系。结果CINⅡ～III和宫颈癌患者HPV感染率均为90％,且以单型别感染为主,分别为70．37％（19／27）、81．94％（118／144）;在CIN II～Ⅲ中HPV58型、52型感染居多,宫颈癌则以HPV16型、18型感染最常见;无论宫颈鳞癌还是宫颈腺癌,以HPV16型检出率最高。结论HPV16型、18型是宫颈癌的主要致病型,不同病理类型并无HPV型别上的差异;宫颈上皮高级别内瘤变则以HPV58型、52型感染为主;对HPV58型、52型感染者应重视随访。     

Cervical cancer screening

Although primary prevention of human papillomavirus (HPV) infections that are causally associated with invasive cervical cancer may be within our grasp, it is unlikely that these approaches will replace existing cervical cancer screening strategies for many years. Experts agree and data support periodic cytology screening for young-adult women using one of several technologies. Recent analyses of cost-effectiveness suggest that the addition of molecular HPV DNA testing for women aged over 30 years may allow the screening interval to be lengthened to 3 years for most women. Women at high risk for HPV infection and its associated cellular atypias warrant closer monitoring and follow-up. These patients would include organ transplant recipients, women exposed to diethylstilbestrol (DES), and HIV-infected women.     

Cervical cancer screening

There is abundant evidence that cervical cancer screening with conventional cytology(CC)has reduced mortality from cervical cancer. Based on the evidence, CC has been implemented as a modality of the population-based screening for the last several decades in Japan. Several issues are currently faced during screening. For instance, very low coverage is one of the greatest unsolved problems. At the same time, a reliable system is required to monitor specimen adequacy and to calculate detection rates of not only invasive cancer, but also cervical intraepithelial neoplasia(CIN), for the quality control and evaluation of screening efficacy. Recently, two new modalities may be applicable for cervical cancer screening. One is liquid-based cytology(LBC)and the other is the HPV test. LBC and CC did not differ significantly in terms of sensitivity and specificity for detection of CIN2+or CIN3+. HPV tests are superior to CC in sensitivity but are inferior in specificity for detection of CIN2+or CIN3+. Because there is a possibility reducing mortality from and incidence of invasive cervical cancer, implementation of these modalities to Japan should be taken into consideration. Prior to this, however, it is necessary to organize a system to compare performance indicators reflecting the effectiveness of the new modalities to those of CC in a population-based screening. Also, these results must be disclosed for a steady perspective on the cervical cancer screening in Japan.     

Cervical cancer screening

Cervical cytology has proved to be one of the most successful examples of cancer screening and has resulted in significant decreases in incidence and mortality from invasive cervical cancer in regions in which comprehensive programs have been instituted. A standardized system of reporting abnormal cervical cytology, the Bethesda System has been developed and revised to reflect our current understanding of HPV-related precancers. The Pap smear has been the backbone of cervical cancer screening programs in North America over the past five decades; however, recent advances, including liquid-based cytology, HPV typing, and direct visualization techniques, are proposed to address the inherent weaknesses of cytologic screening in women who are screened. The problem of unscreened and underscreened women exists and accounts for most cases of invasive cancer. Widespread screening hopefully one day will lead to a significant decrease in the mortality of cervical cancer, the second most common female malignancy worldwide. Another means of preventing this disease involves HPV vaccines, which are in development but are not ready for use outside of a clinical trial.     

宫颈癌及癌前病变早期筛查的新进展

近年来宫颈癌的发病率与死亡率有逐年增长和年轻化趋势,引起了人们的高度重视。目前临床常用的筛查方法主要有肉眼观察法、细胞学检测、HPV －DNA 检测、电子阴道镜检查及组织病理学检查等。本文对宫颈癌及癌前病变最新的筛查指南、筛查方法进行了综述和评价,便于临床工作者能合理应用这些筛查技术或技术联合,有效阻断宫颈癌的发生。     

Cervical cancer screening in Germany

Cervical cancer is one of the target cancers covered by the statutory German cancer screening programme which was introduced in West Germany in 1971 and expanded to the eastern part of the country in 1991. Women covered by statutory health insurance (over 90% of the female population) are eligible to receive an annual cervical examination including a Papanicolaou (PAP) smear beginning at age 20 years. Annual uptake currently slightly exceeds 50% of the eligible population. Shortly after implementation of the national screening programme in the early 1970s the incidence of invasive cervical cancer decreased moderately and the incidence of cervical carcinoma in situ increased substantially in the state of Saarland. These observations would be expected as a result of a cervical cancer screening programme with substantial uptake. Although quality assurance guidelines for cervical cancer screening have been adopted and updated since the inception of the screening programme, only minor changes have been made in the cross-sectional programme documentation. Implementation of population-based documentation and evaluation of screening activities is currently being developed for the German cancer screening programme in pilot studies implementing the European guidelines on the quality assurance of mammography screening. After demonstration of feasibility and effectiveness, improvements in the quality management of breast cancer screening will subsequently be applied to the cervical cancer screening programme.     

Cervical cancer screening in Sweden

Organised cervical cancer screening was implemented in Sweden in the mid-1960s. A marked decline in cervical cancer incidence could be attributed to the time-point of start of screening. Squamous cell carcinoma has declined by 60%, whereas adenocarcinoma has increased. About 950000 papanicolaou (Pap) smears are taken annually. Only 31% of the smears taken in the organised screening programme. As of 1998, the screening guidelines are 3-yearly tests between 23 and 50 years of age and 5-yearly tests between 50 and 60 years of age. The article reviews the screening practise in Sweden, the current efforts to improve the quality of the screening programme, as well as the ongoing randomised evaluations of organised primary screening for cervical human papilloma virus (HPV) infection.     

Cervical cancer screening in Spain

Castilla y León (Spain) is the most extensive region in Europe, with 94147 km(2), and a population of approximately 2.5 million. The programme for the Prevention of Gynaecological Infections and Cancers offers women between 25 and 65 years of age in Castilla y León the possibility to have a cytological test performed every 3 years. The programme was incorporated into the European Network of Cervical Cancer Screening Programmes in 1994. The main results of the 350000 cytological tests performed in the period 1991-1997 are presented.     

Cervical cancer screening in Austria

Austria's target population of women aged 20 years and over consists of 3 million people. There is mainly opportunistic screening, except in one county with a target population of 120000, in which organised screening has been practiced for several years. There are approximately 1.5 million smears annually, exclusively taken by gynaecologists. The recommended screening interval is 1 year. The slides are screened by MTs with a maximum workload of 12000 smears annually in 65 laboratories, mainly headed by pathologists. As shown by Vutuc and colleagues (Wien Klin Wochenschr 1999, 111, 354-359) the opportunistic screening system covers 60% of the Austrian target population leaving an unsatisfactorily high rate of underserved, mainly postmenopausal, women. Nevertheless, the cervical cancer mortality rate could have been decreased to one third during the past 40 years.     

Cervical cancer screening in Ireland

Screening for cervical cancer commenced in Ireland on an opportunistic basis in the late 1960s. The Data Protection Act was recently amended to allow access to specific databases for the purpose of setting up an age sex register for breast and cervical cancer screening. A pilot cervical screening programme is planned for women aged 25-60 years living in the Mid Western Area Health Board region.     

Cervical cancer screening in England

Cervical screening in England is provided free of charge by the National Health Service to all women aged 20-64 years. Computerised call and recall was introduced in 1988 and women receive an invitation every 3-5 years. Smears are taken by the local family doctor, by his/her nurse or at community clinics. Approximately 85% of English women have had a smear in the last 5 years. Quality assurance programmes have recently been established for laboratories and colposcopy clinics and lessons have been learned from previous failures of the service. The incidence has fallen from 16 per 100000 in 1986 to 9.3 per 100000 in 1997. Mortality is currently falling by 7% per year.