P. J. F. Snijders

The Use of General Primers in the Polymerase Chain Reaction Permits the Detection of a Broad Spectrum of Human Papillomavirus Genotypes

A novel polymerase chain reaction (PCR) method was developed that permits the detection of 11 different human papillomavirus (HPV) genotypes using two general primer sets. By computer-assisted sequence analysis, two pairs of general primers were selected from the conserved L1 open reading frame and tested in the PCR on a set of cloned HPV genotypes. Experimental analysis showed that up to three mismatches between primers and target DNA did not influence the efficiency of the assay. The use of these primers in the PCR enabled the detection of HPV genotypes HPV-1a, -6, -8, -11, -13, -16, -18, -30, -31, -32 and -33, and was also successfully applied to well characterized cervical carcinoma cell lines and clinical samples. For the HPV types tested sub-picogram amounts of cloned DNA could be detected after general primer-mediated PCR and subsequent hybridization. The specificity of the amplification products was confirmed by blot hybridization procedures and RsaI restriction enzyme digestion. The results indicate that this PCR method can be a powerful tool for identifying novel HPV genotypes in dysplasias and squamous cell carcinomas suspected of having an HPV aetiology.

Genome-wide DNA copy number alterations in head and neck squamous cell carcinomas with or without oncogene-expressing human papillomavirus

Oncogene-expressing human papillomavirus type 16 (HPV16) is found in a subset of head and neck squamous cell carcinomas (HNSCC). HPV16 drives carcinogenesis by inactivating p53 and pRb with the viral oncoproteins E6 and E7, paralleled by a low level of mutations in TP53 and allelic loss at 3p, 9p, and 17p, genetic changes frequently found in HNSCCs of nonviral etiology. We hypothesize that two pathways to HNSCC exist: one determined by HPV16 and the other by environmental carcinogens. To define the critical genetic events in these two pathways, we now present a detailed genome analysis of HNSCC with and without HPV16 involvement by employing high-resolution microarray comparative genomic hybridization. Four regions showed alterations in HPV-negative tumors that were absent in HPV-positive tumors: losses at 3p11.2–26.3, 5q11.2–35.2, and 9p21.1–24, and gains/amplifications at 11q12.1–13.4. Also, HPV16-negative tumors demonstrated loss at 18q12.1–23, in contrast to gain in HPV16-positive tumors. Seven regions were altered at high frequency (>33%) in both groups: gains at 3q22.2-qter, 5p15.2-pter, 8p11.2-qter, 9q22–34.1, and 20p–20q, and losses at 11q14.1-qter and 13q11–33. These data show that HNSCC arising by environmental carcinogens are characterized by genetic alterations that differ from those observed in HPV16-induced HNSCC, and most likely occur early in carcinogenesis. A number of genetic changes are shared in both tumor groups and can be considered crucial in the later stages of HNSCC progression.

HPV testing and monitoring of women after treatment of CIN 3: review of the literature and meta-analysis.

According to the current guidelines in most western countries, women treated for cervical intraepithelial neoplasia grade 3 (CIN 3) are followed for at least 2 years after treatment by cytology. High-risk human papillomavirus (hrHPV) infections are necessary for the development and maintenance of CIN 3. HrHPV testing could be used to improve monitoring of women treated for CIN 3. This has prompted numerous studies for the implementation of hrHPV testing in monitoring of women treated for CIN 3. Included in this review are 20 studies, published between 1996 and 2003, comparing hrHPV testing with either resection margins or cervical cytology to predict recurrent/residual disease, and 11 of them could be used in a meta-analysis. In the meta-analysis of the 11 studies, the negative predictive value (NPV) for recurrent/residual disease of hrHPV testing was 98% (95% CI 97–99%), that of resection margins 91% (95% CI 87–94%), and that of cervical cytology 93% (95% CI 90–95%). When hrHPV testing was performed in conjunction with cytology, the sensitivity was 96% (95% CI 89–99%), specificity was 81% (95% CI 77–84%), the associated positive predictive value (PPV) was 46% (95% CI 38–54%), and the NPV was 99% (95% CI 98–100%). Combined hrHPV and cytology testing yielded the best test characteristics. We propose to include hrHPV testing in conjunction with cytology for monitoring women treated for CIN 3. Some follow-up visits for women testing negative for both hrHPV and cytology can be skipped. In western countries, this could mean that for women double negative at 6 months, retesting at 12 months should be skipped while keeping the 24-month follow-up visit. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader should be able to describe the various types of HPV detection systems, to compare the various HPV detection methods against the currently available methods of monitoring, and to outline a potential post-treatment management plan for patients treated for HPV-associated cervical neoplasia.

Preferential risk of HPV16 for squamous cell carcinoma and of HPV18 for adenocarcinoma of the cervix compared to women with normal cytology in The Netherlands

We present the type-distribution of high-risk human papillomavirus (HPV) types in women with normal cytology (n=1467), adenocarcinoma in situ (ACIS) (n=61), adenocarcinoma (n=70), and squamous cell carcinoma (SCC) (n=83). Cervical adenocarcinoma and ACIS were significantly more frequently associated with HPV18 (ORMH 15.0; 95% CI 8.6–26.1 and 21.8; 95% CI 11.9–39.8, respectively) than normal cytology. Human papillomavirus16 was only associated with adenocarcinoma and ACIS after exclusion of HPV18-positive cases (ORMH 6.6; 95% CI 2.8–16.0 and 9.4; 95% CI 2.8–31.2, respectively). For SCC, HPV16 prevalence was elevated (ORMH 7.0; 95% CI 3.9–12.4) compared to cases with normal cytology, and HPV18 prevalence was only increased after exclusion of HPV16-positive cases (ORMH 4.3; 95% CI 1.6–11.6). These results suggest that HPV18 is mainly a risk factor for the development of adenocarcinoma whereas HPV16 is associated with both SCC and adenocarcinoma.

Analysis of MHC class I and II expression in relation to presence of HPV genotypes in premalignant and malignant cervical lesions

Cervical intraepithelial neoplasia (CIN) grades I to III lesions (n = 94) and squamous cell carcinomas of the uterine cervix (n = 27) were analysed for MHC class I and II expression and presence of HPV genotypes. MHC class I and II expression was studied by immunohistochemistry and HPV typing was performed by general primer- and type-specific primer mediated PCR (GP/TS PCR). Both techniques were performed on paraffin embedded tissue sections. Results show disturbed MHC class I heavy chain expression in CIN I to CIN III, as well as in cervical carcinomas. Upregulated MHC class II expression on dysplastic epithelial cells was also found in the different CIN groups and carcinomas. Prevalence of HPV genotypes increased with the severity of the lesion, mainly due to the contribution of the HPV types 16 and 18. No correlation could be established between the presence of specific HPV genotypes and any MHC expression pattern in the different CIN groups or cervical carcinomas. In some cases these data were confirmed by RNA in situ hybridisation showing HPV 16 E7 transcripts in the same dysplastic/neoplastic cells from which MHC status was determined. The results indicate that local differences may exist in the type of cellular immune response to HPV induced lesions.

Sequential gene promoter methylation during HPV-induced cervical carcinogenesis.

We aimed to link DNA methylation events occurring in cervical carcinomas to distinct stages of HPV-induced transformation. Methylation specific-multiplex ligation-dependent probe amplification (MS-MLPA) analysis of cervical carcinomas revealed promoter methylation of 12 out of 29 tumour suppressor genes analysed, with MGMT being most frequently methylated (92%). Subsequently, consecutive stages of HPV16/18-transfected keratinocytes (n=11), ranging from pre-immortal to anchorage-independent phenotypes, were analysed by MS-MLPA. Whereas no methylation was evident in pre-immortal cells, progression to anchorage independence was associated with an accumulation of frequent methylation events involving five genes, all of which were also methylated in cervical carcinomas. TP73 and ESR1 methylation became manifest in early immortal cells followed by RARβ and DAPK1 methylation in late immortal passages. Complementary methylation of MGMT was related to anchorage independence. Analysis of nine cervical cancer cell lines, representing the tumorigenic phenotype, revealed in addition to these five genes frequent methylation of CADM1, CDH13 and CHFR. In conclusion, eight recurrent methylation events in cervical carcinomas could be assigned to different stages of HPV-induced transformation. Hence, our in vitro model system provides a valuable tool to further functionally address the epigenetic alterations that are common in cervical carcinomas.

Increased gene copy numbers at chromosome 20q are frequent in both squamous cell carcinomas and adenocarcinomas of the cervix

Genome‐wide microarray‐based comparative genomic hybridization (array CGH) was used to identify common chromosomal alterations involved in cervical carcinogenesis as a first step towards the discovery of novel biomarkers. The genomic profiles of nine squamous cell carcinomas (SCCs) and seven adenocarcinomas (AdCAs), as well as four human papillomavirus (HPV)‐immortalized keratinocyte cell lines, were assessed. On a genome‐wide scale, SCCs showed significantly more gains than AdCAs. More specifically, there was a striking and highly significant difference between the two histological types for gain at 3q12.1–28, which was predominantly observed in SCC. Other frequent alterations included gains of 1q21.1–31.1 and 20q11.21–13.33, and losses of 11q22.3–25 and 13q14.3–21.33. Subsequent FISH analysis for hTR, located at 3q26, confirmed the presence of 3q gain in SCCs and HPV‐immortalized cell lines. Fine mapping of chromosome 20q using multiplex ligation‐dependent probe amplification (MLPA) showed copy number increases for a number of genes located at 20q11–q12, including DNMT3B and TOP1. For DNMT3B, this correlated with elevated mRNA expression in 79% of cases. In conclusion, the assessment of frequent genomic alterations resulted in the identification of potential novel biomarkers, which may ultimately enable a better risk stratification of high‐risk (hr)‐HPV‐positive women. Copyright

HPV presence precedes abnormal cytology in women developing cervical cancer and signals false negative smears

In a retrospective case–control study, we investigated high-risk HPV DNA presence by general primer GP5+/6+ PCR in the last normal cervical smear in the patient archives (i.e. baseline smear) of 57 women who later developed cervical cancer. Also, normal cervical smears of 114 age-matched control women were analysed. High-risk HPV DNA was detected in 37 of the 57 (65%) baseline smears of the case women, and 7 (6%) of 114 smears of the control women (OR 28, 95% Cl 11–72). The HPV positive subsequent smears and cervical cancer biopsies of the case women contained the same HPV type as was detected in the baseline smear. After cytological revision, the baseline smears of 48 case women (84%) were reclassified as abnormal, 33 (69%) of which scored high-risk HPV DNA positive. Ultimately, an undisputable normal baseline smear was found in only 10 case women. In 7 (70%) of them this smear was HPV positive, whereas only 7 (7%) of 104 revised, undisputable normal smears of control women were high-risk HPV positive (OR 32, 95% Cl 6.8–153). The results showed that (1) high-risk HPV presence precedes abnormal cytology in women who develop cervical cancer, and (2) high-risk HPV testing signals false-negative smears of women at risk of cervical cancer.

High-risk HPV type-specific clearance rates in cervical screening

We assessed clearance rates of 14 high-risk human papillomavirus (hrHPV) types in hrHPV-positive women with normal cytology and borderline/mild dyskaryosis (BMD) in a population-based cervical screening cohort of 44 102 women. The 6-month hrHPV type-specific clearance rates, that is, clearance of the same type as detected at baseline, in women with normal and BMD smears were 43% (95% confidence interval (CI) 39–47) and 29% (95% CI 24–34), respectively. Corresponding 18-month clearance rates were markedly higher, namely 65% (95% CI 60–69) and 41% (95% CI 36–47), respectively. The lowest clearance rates in women with normal cytology were observed for HPV16, HPV18, HPV31, and HPV33. Significantly reduced 18-month clearance rates at a significance level of 1% were observed for HPV16 (49%, 95% CI 41–59) and HPV31 (50%, 95% CI 39–63) in women with normal cytology, and for HPV16 (19%, 95% CI 12–29) in women with BMD. Among women who did not clear hrHPV, women with HPV16 persistence displayed an increased detection rate of ⩾CIN3 (normal P<0.0001; BMD, P=0.005). The type-specific differences in clearance rates indicate the potential value of hrHPV genotyping in screening programs. Our data support close surveillance (i.e. referral directly, or within 6 months) of women with HPV16 and are inconclusive for surveillance of women with HPV18, HPV31, and HPV33. For the other hrHPV-positive women, it seems advisable to adopt a conservative management with a long waiting period, as hrHPV clearance is markedly higher after 18 months than after 6 months and the risk for ⩾CIN3 is low.

Clinical Validation of the cobas 4800 HPV Test for Cervical Screening Purposes

ABSTRACT This study shows that the clinical performance and reproducibility of the cobas 4800 HPV test for high-risk human papillomavirus (HPV) detection fulfill the criteria as formulated in international guidelines of HPV test requirements for cervical screening purposes. Accordingly, the cobas 4800 HPV test can be considered clinically validated for cervical screening.