Search PubMed⌕ Search

Biomedical subjects

P J F Snijders

Publications and source records attributed to P J F Snijders.

At least 19 recordsLinked to original sources
PubMed2006

Human papillomavirus infection in Shenyang City, People's Republic of China: A population-based study.

To investigate the prevalence of, and risk factors for, cervical infection with human papillomavirus (HPV) in Shenyang City, People's Republic of China, we interviewed and obtained cervical cell samples from 685 women aged 15-59 years enumerated from local population lists. Human papillomavirus DNA was detected in cervical cell samples using a GP5+/6+-based PCR assay for 44 HPV types. Human papillomavirus prevalence was 16.8% overall and 13.6% among women without cervical abnormalities (16.6% and 12.4%, respectively, age-standardised to the world standard population), with no significant trends in HPV prevalence by age group. Of the 32 types identified, high-risk HPV types predominated in all age groups, HPV16 being the most common (3.4% of all women), followed by HPV52 (2.5%) and 58 (1.9%). Multiple-type infections accounted for 31.3% of all infected women. Not being married, reporting multiple sexual partners and husband's extramarital sexual relationships were all significantly associated with being HPV-positive. The disclosure of a relatively high HPV prevalence in Shenyang, in comparison with other worldwide populations, raises important questions concerning the prevention of cervical cancer in China, especially given the promising efficacy of prophylactic HPV vaccines.

Adolescent↗
PubMed2006

Implementation of human papillomavirus testing in cervical screening without a concomitant decrease in participation rate.

Adding high-risk human papillomavirus (hrHPV) testing to screening increases the efficacy of cervical screening programmes. However, hrHPV testing may result in a lower participation rate because of the perceived association with sexually transmitted infections. We describe how testing for hrHPV was added to cervical screening in the POpulation-BAsed SCreening study AMsterdam (POBASCAM) trial. Participation rates of the screening programme before and after hrHPV implementation were evaluated in the region where the POBASCAM trial was carried out. The participation rate was 58.7% before and 61.4% after the addition of hrHPV testing to screening (p<0.001). An inventory of frequently asked questions is presented. Thus, hrHPV testing can be added to cervical screening by cytology without a decrease in participation rate.

Adult↗
PubMed2006

Human papillomavirus infection in Shanxi Province, People's Republic of China: a population-based study.

To investigate the prevalence of, and risk factors for, cervical infection with human papillomavirus (HPV) in the rural province of Shanxi, People's Republic of China, which has relatively high cervical cancer mortality rates, we interviewed and obtained cervical cell samples from 662 women aged 15-59 years. A total of 24 different HPV types were identified using a GP5+/6+-based PCR assay able to detect 44 different HPV types. Human papillomavirus prevalence was 14.8% overall and 9.6% among women without cervical abnormalities (14.2 and 8.9%, respectively, age standardised to the world standard population). Multiple-type infections accounted for 30.6% of all infections. By far the most commonly found type was HPV16 (5.7% of all women and 38.8% of HPV-positive women), followed by HPV 58, 52, 33 and 18. Unlike most previous studies published, HPV prevalence was lower among women younger than 35 years (8.7%) than those older than 35 years (17.8%). High-risk HPV types predominated in all age groups. Although low-risk HPV types were rare in young women, they became more common with increasing age. 92.3% of women with cervical intraepithelial neoplasia grade 3 were infected with high-risk HPV types, but none with low-risk types only. No significant difference in HPV positivity was observed by educational level, sexual habits, reproductive history or use of contraceptive methods in this rural low-income Chinese population.

Adolescent↗
PubMed2006

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.

Adult↗
PubMed2006

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 (OR(MH) 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 (OR(MH) 6.6; 95% CI 2.8-16.0 and 9.4; 95% CI 2.8-31.2, respectively). For SCC, HPV16 prevalence was elevated (OR(MH) 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 (OR(MH) 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.

Adenocarcinoma↗
PubMed2006

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.

Adenocarcinoma↗
PubMed2006

Cross-sectional comparison of an automated hybrid capture 2 assay and the consensus GP5+/6+ PCR method in a population-based cervical screening program.

In this cross-sectional study, clinical performances of the hybrid capture 2 assay using an automated instrument (i.e., rapid capture system) (hc2-RCS) and the high-risk human papillomavirus GP5+/6+ PCR-enzyme immunoassay (EIA) test were compared using cervical scrape specimens from 8,132 women that participated in a population-based screening trial. The hc2-RCS test scored significantly more samples positive (6.8%) than the GP5+/6+ PCR-EIA (4.8%) (P < 0.0005). This could be attributed largely to a higher positivity rate by the hc2-RCS test for women with cytologically normal, borderline, or mild dyskaryosis. A receiver operator characteristics analysis of the semiquantitative hc2-RCS results in relation to different cytology categories revealed that these differences are owing to differences in assay thresholds. For women classified as having moderate dyskaryosis or worse who also had underlying histologically confirmed cervical intraepithelial neoplasia grade 3 or cervical cancer (> or =CIN3), the hc2-RCS scored 97% (31/32) of samples positive, versus 91% (29/32) by GP5+/6+ PCR-EIA. However, this difference was not significant (P = 0.25). After increasing the hc2-RCS cutoff from 1.0 to 2.0 relative light units/cutoff value of the HPV16 calibrator (RLU/CO), no additional CIN3 lesions were missed by hc2-RCS, but the number of test-positive women with normal, borderline, or mild dyskaryosis was significantly decreased (P < 0.0005). However, at this RLU/CO, the difference in test positivity between hc2-RCS and the GP5+/6+ PCR-EIA was still significant (P = 0.02). The use of an RLU/CO value of 3.0 revealed no significant difference between hc2-RCS and GP5+/6+ PCR-EIA results, and equal numbers of smears classified as > or =CIN3 (i.e., 29/32) were detected by both methods. In summary, both assays perform very well for the detection of >or =CIN3 in a population-based cervical screening setting. However, adjustment of the hc2-RCS threshold to an RLU/CO value of 2.0 or 3.0 seems to produce an improved balance between the clinical sensitivity and specificity for > or =CIN3 in population-based cervical screening.

Automation↗
PubMed2005

Effects of HPV detection in population-based screening programmes for cervical cancer; a Dutch moment.

Presently, large randomised studies are investigating the value of incorporating HPV detection in population-based cervical screening programmes to improve the effectiveness of these programmes. None of these studies, however, has assessed the effect of HPV detection on the participation rate of women in these screening programmes. This paper draws attention to the fact that the effectiveness of cervical screening largely depends on the participation rate. A number of possibilities will be addressed on how HPV may affect cervical cancer screening. On the one hand, an option is described that addition of HPV detection, although increasing the sensitivity of screening, may in fact decrease the overall effectiveness of the screening. On the other hand, the possibility is put forward that incorporation of HPV will increase the reduction in mortality because of increased sensitivity and participation to the screening. Our manuscript thereby addresses an important aspect of screening, namely, the societal impact of new diagnostic tests on coverage in population-based screening programmes.

Female↗
PubMed2005

Long-term protective effect of high-risk human papillomavirus testing in population-based cervical screening.

We prospectively evaluated the 5-year predictive values of adding high-risk human papillomavirus (hrHPV) testing to cytology for the detection of > or = cervical intraepithelial neoplasia (CIN)3 lesions in a population-based cohort of 2810 women. At baseline, nine (0.3%) women had prevalent lesions > or = CIN3, all being hrHPV positive. After 5 years of follow-up, four (6.5%) of the 62 hrHPV-positive women with normal cytology developed lesions > or = CIN3, vs only one (0.05%) of the 2175 hrHPV-negative women with normal cytology. High-risk human papillomavirus testing or combined screening revealed a much higher sensitivity, at the cost of a small decrease in specificity, and a higher negative predictive value for the detection of lesions > or = CIN3 till the next screening round (5 years) than cytology alone.

Female↗
PubMed2005

HPV type concordance in sexual couples determines the effect of condoms on regression of flat penile lesions.

We earlier demonstrated, in a randomised clinical trial, that the regression time of flat penile lesions in male sexual partners of women with cervical intraepithelial neoplasia (CIN) was shorter in men who used condoms compared to those who did not. To further evaluate this finding, we examined whether the effect of condom use on the regression of flat penile lesions depends on the presence of human papillomavirus (HPV) type concordance in sexual couples, as determined in cervical and penile scrapes by GP5+/6+ PCR testing. A Cox model with time-dependent covariates showed a beneficial effect of condoms on regression of flat penile lesions in concordant couples (hazard ratio 2.63, 95% CI 1.07-6.48) but not in those who were nonconcordant. When both partners harboured different HPV types, no effect of condoms was found (hazard ratio 0.90, 95% CI 0.27-2.96). Delayed regression of flat penile lesions was associated with either stable lesions or with new penile lesions developing at sites surrounding pre-existing lesions suggesting reinfection of the penile epithelium. We conclude that condom use blocks sexual HPV transmission by preventing reinfection and development of new penile lesions in men who are susceptible to the same type as present in the female partner.

Adult↗
PubMed2005

Papillomavirus infection in rural women in southern India.

To investigate the prevalence of, and the risk factors for, cervical infection with 44 types of human papillomavirus (HPV) in a rural area in the Dindigul District, Tamil Nadu, India, we interviewed and obtained cervical cell samples from 1891 married women aged 16-59 years. HPV prevalence was 16.9% overall and 14.0% among women without cervical abnormalities, or 17.7 and 15.2%, respectively, age-standardised to the world standard population. In all, 21.9% of infections involved more than one HPV type. High-risk HPV types predominated, particularly HPV 16 (22.5% of women infected), followed by HPV 56, HPV 31, HPV 33 and HPV 18. Unlike most populations studied in developed countries, HPV prevalence was constant across the age groups. HPV positivity was inversely associated with education level (odds ratio (OR) among women with high school vs no education=0.6) and positively associated with widowhood and divorce (OR=1.7), nulligravidity (OR=2.3), and condom use (OR=2.6). It is unclear how much low clearance of, or frequent reinfection with HPV accounted for the study prevalence of infection in different age groups.

Adolescent↗
PubMed2005

Expression of the p16(INK4a) gene product, methylation of the p16(INK4a) promoter region and expression of the polycomb-group gene BMI-1 in squamous cell lung carcinoma and premalignant endobronchial lesions.

It is generally assumed that squamous cell carcinoma develops in a stepwise manner from normal bronchial epithelium towards cancer by the accumulation of (epi)genetic alterations. Several mechanisms including mutations and homozygous deletions or hypermethylation of the p16(INK4a) promoter region can cause loss of p16 expression. Recent studies suggest overexpression of the polycomb-group gene BMI-1 might also down-regulate p16 expression. In this study, we analyzed the p16 expression in relation to the methylation status of the p16 promoter region of the p16(INK4a) gene and the expression of BMI-1 in bronchial squamous cell carcinomas (SCC) and its premalignant lesions. Nine (69%) SCC showed loss of p16 expression and 10 (77%) showed expression of BMI-1. Of four p16 positive samples two (50%) were BMI-1 positive, whereas among nine p16 negative samples, eight (89%) revealed BMI-1 staining. Four (44%) p16 negative samples were hypermethylated at the p16(INK4a) promoter region; the other p16 negative tumors that showed no hypermethylation revealed BMI-1 staining. Only two premalignant lesions showed absence of p16 expression, of which one (carcinoma in situ) was hypermethylated at the p16(INK4a) promoter region and the other (severe dysplasia) showed BMI-1 expression. In total, 11 precursor lesions (48%) revealed BMI-1 expression. In conclusion, the results of this study suggest that loss of p16 expression by promoter hypermethylation is inconsistently and occurs late in the carcinogenic process at the level of severe dysplasia. To what extent overexpression of the polycomb-group protein BMI-1 attributes to down regulating of p16 expression remains unclear.

Aged↗
PubMed2005

Clinical relevance of human papillomavirus testing in cytopathology.

Cancer of the uterine cervix is the second most common cancer in women worldwide. Currently, cervical screening is based on cytology alone. Because infection with high-risk human papillomavirus types (hrHPVs) is a necessary cause of cervical cancer, it has been postulated that screening might become more efficient when it is based on combined cytology and hrHPV testing. In this review we will discuss the advantages of added HPV tests in cervical cancer screening, as a quality control for false-negative smears, in triage of women with equivocal smears, in follow-up of women treated for CIN3 or cervical cancer and for the detection of cervical adenocarcinoma.

Adenocarcinoma↗
PubMed2005

Comparison of three different PCR methods for quantifying human papillomavirus type 16 DNA in cervical scrape specimens.

We compared real-time LightCycler and TaqMan assays and the GP5+/6+ PCR/enzyme immunoassay (EIA) to assess the human papillomavirus type 16 (HPV16) load in cervical scrape specimens. Both real-time PCR assays determined the HPV16 load in scrape specimens similarly. The level of agreement between these assays and the GP5+/6+ PCR/EIA was low (P = 0.004), suggesting that the latter method is not suited for quantifying HPV16 DNA.

Cervix Uteri↗
PubMed2005

A shift to a peripheral Th2-type cytokine pattern during the carcinogenesis of cervical cancer becomes manifest in CIN III lesions.

BACKGROUND: A shifted balance between T helper 1 (Th1)-type and Th2-type cytokines has been hypothesised in cervical dysplasia. AIMS: To evaluate possible deregulation of the cytokine network by estimating the expression of peripheral cytokines in different stages of cervical disease and in relation to the presence or absence of high risk human papillomavirus (HR-HPV). METHODS: Twenty one HR-HPV positive women with high grade cervical intraepithelial neoplasia (CIN II-III) and 12 patients with invasive cervical carcinoma formed the study groups. Two control groups consisted of 10 HR-HPV positive and 11 HR-HPV negative women without CIN. Differences in leucocyte subgroups were evaluated by a differential leucocyte count. Plasma concentrations of tumour necrosis factor alpha (TNFalpha), TNFalpha receptors TNFRI and TNFRII, interferon gamma (IFNgamma), interleukin 2 (IL-2), IL-12, IL-4, and IL-10 were determined by enzyme linked immunosorbent assays. RESULTS: Leucocyte counts in patients with CIN III and carcinoma were significantly higher than in controls. Plasma IFNgamma concentrations were significantly lower in patients with CIN III and carcinoma than in women with CIN II or controls. Plasma concentrations of IL-12, IL-2, IL-4, and TNFalpha did not differ significantly between groups, but significantly lower plasma concentrations of TNFRII were found in CIN III and carcinoma compared with CIN II. IL-10 was detected with increased frequency in the plasma of patients with CIN III and carcinoma. CONCLUSIONS: These results indicate that a shift to a Th2-type cytokine pattern during the carcinogenesis of cervical cancer occurs in women with CIN III lesions.

Adult↗
PubMed2004

Prevalence of papillomavirus infection in women in Ibadan, Nigeria: a population-based study.

To investigate the prevalence of and the risk factors for cervical infection with human papillomavirus (HPV) in an inner-city area of Ibadan, Nigeria, we interviewed and obtained a sample of cervical cells from 932 sexually active women aged 15 years or older. A total of 32 different HPV types were identified with an HPV prevalence of 26.3% overall and 24.8% among women without cervical lesions; or age-standardised to the world standard population of 28.3 and 27.3%, respectively. High-risk HPV types predominated, most notably HPV 16, 31, 35 and 58. In all, 33.5% of infections involved more than one HPV type. Unlike most populations studied so far, HPV prevalence was high not only among young women, but also in middle and old age. Single women (odds ratio, OR=2.1; 95% confidence interval, CI=1.1-3.9) and illiterate women (OR=1.7; 95%CI=1.1-2.5) showed increased HPV positivity. Associations were also found with anti-Herpes simplex-2 antibodies (OR=1.6; 95% CI: 1.1-2.1) and with the husband's extramarital relationships (OR=1.6: 95% CI: 1.0-2.6). High prevalence of HPV in all age groups may be a distinctive feature of populations where HPV transmission continues into middle age and cervical cancer incidence is very high.

Adolescent↗
PubMed2004

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.

Cervix Uteri↗