Stefanie J. Klug

TP53 codon 72 polymorphism and cervical cancer: a pooled analysis of individual data from 49 studies.

BACKGROUND Cervical cancer is caused primarily by human papillomaviruses (HPV). The polymorphism rs1042522 at codon 72 of the TP53 tumour-suppressor gene has been investigated as a genetic cofactor. More than 80 studies were done between 1998 and 2006, after it was initially reported that women who are homozygous for the arginine allele had a risk for cervical cancer seven times higher than women who were heterozygous for the allele. However, results have been inconsistent. Here we analyse pooled data from 49 studies to determine whether there is an association between TP53 codon 72 polymorphism and cervical cancer. METHODS Individual data on 7946 cases and 7888 controls from 49 different studies worldwide were reanalysed. Odds ratios (OR) were estimated using logistic regression, stratifying by study and ethnic origin. Subgroup analyses were done for infection with HPV, ethnic origin, Hardy-Weinberg equilibrium, study quality, and the material used to determine TP53 genotype. FINDINGS The pooled estimates (OR) for invasive cervical cancer were 1.22 (95% CI 1.08-1.39) for arginine homozygotes compared with heterozygotes, and 1.13 (0.94-1.35) for arginine homozygotes versus proline homozygotes. Subgroup analyses showed significant excess risks only in studies where controls were not in Hardy-Weinberg equilibrium (1.71 [1.21-2.42] for arginine homozygotes compared with heterozygotes), in non-epidemiological studies (1.35 [1.15-1.58] for arginine homozygotes compared with heterozygotes), and in studies where TP53 genotype was determined from tumour tissue (1.39 [1.13-1.73] for arginine homozygotes compared with heterozygotes). Null results were noted in studies with sound epidemiological design and conduct (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes), and studies in which TP53 genotype was determined from white blood cells (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes). INTERPRETATION Subgroup analyses indicated that excess risks were most likely not due to clinical or biological factors, but to errors in study methods. No association was found between cervical cancer and TP53 codon 72 polymorphism when the analysis was restricted to methodologically sound studies. FUNDING German Research Foundation (DFG).

Comparison of the performance of different HPV genotyping methods for detecting genital HPV types

Classification of high‐risk HPV types for cervical cancer screening depends on epidemiological studies defining HPV type‐specific risk. The genotyping tests that are used, are however, not uniform with regard to type‐specific detection rates making comparisons between different studies difficult. To overcome the lack of a “gold standard” four tests were evaluated crosswise using 824 cervical smears pretested by HC2. The tests evaluated were the L1‐PCR‐based assays PGMY09/11 LBA, HPV DNA Chip and SPF LiPA and an E1 consensus PCR followed by cycle sequencing (E1‐PCR). A subset of 265 samples was tested in addition with the GP5+/6+ reverse line blot assay. Differences were noted in the sensitivity and range for specific HPV types, e.g. with detection rates for HPV53 ranging from 2.3% to 11.6%. HPV16 was the most prevalent type detected by all tests except for the SPF‐10 LiPa, which detected HPV31 more often. Kappa values calculated ranged from poor (k = 0.20) to intermediate (k = 0.54) for HPV positivity, but were higher for high‐risk type positivity (k = 0.31–0.61) and best for recognition of HPV16 (k = 0.53–0.72). The analytical sensitivity of the tests ranged between 15% and 97% for individual types and specificity was highly dependent on which test system was used as “gold standard” for the analysis. The results of histology were used for calculation of clinical sensitivity and specificity. E1‐PCR, PGMY09/11 LBA and SPF‐10 LiPA had a high clinical sensitivity (>95%) for the detection of cervical intraepithelial neoplasia 2 or higher, whereas the HPV DNA Chip reached only 84.1%. J. Med. Virol. 80: 1264–1274, 2008.

TP53 mutation pattern of esophageal squamous cell carcinomas in a high risk area (Southern Brazil): role of life style factors.

In an attempt to correlate the TP53 mutation pattern of squamous cell carcinomas of the esophagus (ESCC) and life style factors of patients from the high risk area Rio Grande do Sul, Brazil, 135 ESCC were analyzed, after prescreening by p53 immunohistochemistry, by SSCP and DNA sequencing of TP53, exon 5–9. Forty‐nine somatic TP53 mutations (and 1 case with p53 polymorphism) were identified as missense (n = 39), frameshift (n = 6), silent (n = 1), amber (n = 1) or intron border mutations (n = 2) that cause splicing aberrations. They were preferentially found in exon 5 (36.7%) and exon 8 (32.7%). Several mutations were located in the mutation hot spot codons 248, 273 and 282, mainly at CpG sites. Transition mutations were observed in 53.1% (among them 50% G > A), transversion mutations in 34.7% (among them 47.1% G > T) and frameshifts in 12.2%, the latter 2 mainly in smokers and alcohol drinkers. Transitions were more prevalent in females than in males (p < 0.05). TP53 mutations, mainly transversions, were more frequently found in heavy smokers (p = 0.03), with the same tendency after chronic alcohol consumption. Comparison with the worldwide IARC database disclosed differences in the TP53 mutation pattern of the Brazilian tumors, with a higher accumulation of TP53 mutations in exon 8 and a higher prevalence of transition mutations. Mutations at the reported hot spot codon 176 were missing. Although difficult because of the documented coexposure to various life style risk factors in most patients of this series, the hypothesis is proposed that besides smoking and alcohol drinking the commonly consumed hot mate tea in this high risk area for ESCC is responsible for this different pattern of TP53 mutations because of chronic hyperthermic irritation and inflammation in the esophagus with an endogenous formation of radicals or carcinogenic factors that lead to a higher prevalence of transition mutations.

Systematic literature reviews and meta-analyses: part 6 of a series on evaluation of scientific publications.

BACKGROUND Because of the rising number of scientific publications, it is important to have a means of jointly summarizing and assessing different studies on a single topic. Systematic literature reviews, meta-analyses of published data, and meta-analyses of individual data (pooled reanalyses) are now being published with increasing frequency. We here describe the essential features of these methods and discuss their strengths and weaknesses. METHODS This article is based on a selective literature search. The different types of review and meta-analysis are described, the methods used in each are outlined so that they can be evaluated, and a checklist is given for the assessment of reviews and meta-analyses of scientific articles. RESULTS Systematic literature reviews provide an overview of the state of research on a given topic and enable an assessment of the quality of individual studies. They also allow the results of different studies to be evaluated together when these are inconsistent. Meta-analyses additionally allow calculation of pooled estimates of an effect. The different types of review and meta-analysis are discussed with examples from the literature on one particular topic. CONCLUSIONS Systematic literature reviews and meta-analyses enable the research findings and treatment effects obtained in different individual studies to be summed up and evaluated.

The Efficacy and Duration of Vaccine Protection Against Human Papillomavirus: A Systematic Review and Meta-analysis

BACKGROUND The German Standing Committee on Vaccination (STIKO) recommends vaccination against human papillomaviruses (HPV) of the high-risk types 16 and 18. The duration of protection afforded by HPV vaccines has been reported in multiple studies to date but has not been systematically evaluated. METHOD Systematic literature review and meta-analysis on the efficacy of vaccination, with assessment of evidence by the GRADE criteria (Grading of Recommendations Assessment, Development and Evaluation). RESULTS 15 studies were identified: 10 randomized controlled trials (RCTs) and 5 observational studies. The RCTs included a total of 46 436 participants. The duration of follow-up was short (median, 3 years) in 8 RCTs and long (median, 6 years) in 2 RCTs. During the period of short-term follow up, the pooled efficacy of vaccination for the study endpoint of incident HPV infection (percentage of infections prevented) was 83% (95% confidence interval [CI]: 70-90% ), while the pooled efficacy against persistent HPV infection was 90% (95% CI: 79-95% ). In this period, CIN 2+ lesions were prevented with 84% efficacy (95% CI: 50-95% ), and CIN 3+ lesions with 94% efficacy (95% CI: 83-98% ). During the period of long-term follow-up, incident infections were prevented with 94% efficacy (95% CI: 80-98% ) and persistent infections with 95% efficacy (95% CI: 84-99% ). The long-term efficacy against CIN 2+ lesions was 86% (95% CI: -166-99% ). No data are available on the long-term efficacy of vaccination against CIN 3+ lesions. CONCLUSION Long-term observation does not indicate any loss of antiviral protection after vaccination against HPV 16 and 18, although the evidence for long-term protection is of lesser quality than that for short-term protection.

Influence of GSM signals on human peripheral lymphocytes: study of genotoxicity.

Exposure to radiofrequency (RF) electromagnetic fields (EMF) is continuously increasing worldwide. Yet, conflicting results of a possible genotoxic effect of RF EMF continue to be discussed. In the present study, a possible genotoxic effect of RF EMF (GSM, 1,800 MHz) in human lymphocytes was investigated by a collaboration of six independent institutes (institutes a, b, c, d, e, h). Peripheral blood of 20 healthy, nonsmoking volunteers of two age groups (10 volunteers 16–20 years old and 10 volunteers 50–65 years old) was taken, stimulated and intermittently exposed to three specific absorption rates (SARs) of RF EMF (0.2 W/kg, 2 W/kg, 10 W/kg) and sham for 28 h (institute a). The exposures were performed in a setup with strictly controlled conditions of temperature and dose, and randomly and automatically determined waveguide SARs, which were designed and periodically maintained by ITIS (institute h). Four genotoxicity tests with different end points were conducted (institute a): chromosome aberration test (five types of structural aberrations), micronucleus test, sister chromatid exchange test and the alkaline comet assay (Olive tail moment and % DNA). To demonstrate the validity of the study, positive controls were implemented. The genotoxicity end points were evaluated independently by three laboratories blind to SAR information (institute c = laboratory 1; institute d = laboratory 2; institute e = laboratory 3). Statistical analysis was carried out by institute b. Methods of primary statistical analysis and rules to adjust for multiple testing were specified in a statistical analysis plan based on a data review before unblinding. A linear trend test based on a linear mixed model was used for outcomes of comet assay and exact permutation test for linear trend for all other outcomes. It was ascertained that only outcomes with a significant SAR trend found by at least two of three analyzing laboratories indicated a substantiated suspicion of an exposure effect. On the basis of these specifications, none of the nine end points tested for SAR trend showed a significant and reproducible exposure effect. Highly significant differences between sham exposures and positive controls were detected by each analyzing laboratory, thus validating the study. In conclusion, the results show no evidence of a genotoxic effect induced by RF EMF (GSM, 1,800 MHz).

Incidence Patterns and Temporal Trends of Invasive Nonmelanotic Vulvar Tumors in Germany 1999-2011. A Population-Based Cancer Registry Analysis

Objectives Time trends on the incidence and characteristics of invasive vulvar cancer in Germany have so far been studied in few local population- and hospital based tumor registries. We aimed to provide an overview on recent developments of vulvar cancer in Germany, using population-based cancer registry data. Methods We analyzed the data on vulvar cancer of eight population-based German cancer registries for the period 1999-2011. ICD-10 codes and ICD-O-3 morphology codes were used to select site and histologic types. The annual percentage change was calculated on age-adjusted incidence rates with a joinpoint regression model. Results A total of 12,711 registered cases of invasive carcinoma of the vulva were included in the analyses, hereof were 12,205 of squamous cell origin. Age-standardized incidence rates of vulvar cancer annually increased by 6.7% (95% confidence limits: 5.6-7.9) from 1.7 per 100,000 women in 1999 to 3.6 per 100,000 women in 2011. An increase was observed among women of all ages, and especially between 30 and 69 years of age. Conclusion The annual incidence of invasive carcinoma of the vulva nearly doubled in the past decade in Germany, considerably exceeding the rates observed in other Western European countries. A combination of changes in risk factors, and documentation practice might have contributed to the observed substantial increase in vulvar cancer incidence.

Data Analysis of Epidemiological Studies: Part 11 of a Series on Evaluation of Scientific Publications

INTRODUCTION An important objective of epidemiological research is to identify risk factors for disease. Depending on the particular question being asked, cohort studies, case-control studies, or cross-sectional studies are conducted. METHODS Methods of data analysis in different types of epidemiological studies are illustrated through examples with fictive data. Important measures of frequency and effect will be introduced. Different regression models will be presented as examples of complex analytical methods. RESULTS Important frequency measures in cohort studies are incidence and mortality. Important effect measures such as the relative risk (RR), hazard ratio (HR), standardized incidence ratio (SIR), standardized mortality ratio (SMR), and odds ratio (OR) can also be calculated. In case-control or cross-sectional studies, the OR can be calculated as an effect measure. In cross-sectional studies, prevalence is the most important frequency measure. The interpretation of different frequency measures and effect measures will be discussed. CONCLUSION The measures to be calculated and the analyses to be performed in an epidemiological study depend on the research questions being asked, the study type, and the available data.

Early Detection of Cervical Carcinomas: Finding an Overall Approach

BACKGROUND Infection with human papillomavirus (HPV) is a necessary, but not sufficient condition for the emergence of cervical cancer. Cervical cancer develops over several years through a series of precursor lesions that can be detected by cytological screening. The majority of these lesions, however, regress spontaneously. The challenge of cancer screening is to detect those patients who are at high risk of tumor progression. METHODS Selective literature review on cervical cancer screening in light of current guidelines and recommendations. RESULTS AND CONCLUSION Since the recently introduced vaccination against HPV does not provide full protection against cervical cancer, screening programs must continue. HPV vaccination and early detection of cervical carcinomas should be organized into a combined prevention program with systematic documentation, quality control, and active invitation to participate. It is assumed that the reduction in prevalence of precancerous lesions as a result of vaccination will have a negative impact on the efficiency of cytological early detection. Therefore, the existing screening procedures should be optimized and complemented by new techniques. Already available for screening is the detection of HPV DNA. Further promising biomarkers are currently being investigated in international studies, but no conclusions on their potential efficacy can yet be drawn.

Health-related quality of life for pre-diabetic states and type 2 diabetes mellitus: a cross-sectional study in Västerbotten Sweden

BackgroundType 2 diabetes (T2D) decreases health-related quality of life, but there is a lack of information about the health status of people in pre-diabetic states. However, information on health utility weights (HUWs) for pre-diabetic states and T2D are essential to estimate the effect of prevention initiatives. We estimated and compared HUWs for healthy individuals, those with pre-diabetes and those with T2D in a Swedish population and evaluated the influence of age, sex, education and body mass index on HUWs.MethodsParticipants of the Västerbotten Intervention Program, Sweden, between 2002 and 2012, who underwent an oral glucose tolerance test or indicated they had T2D and who filled in the Short Form-36 questionnaire (SF-36) were included. Individuals were categorized as healthy, being in any of three different pre-diabetic states, or as T2D. The pre-diabetic states are impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or a combination of both (IFG&IGT). The SF-6D index was used to convert SF-36 responses to HUWs. HUWs were stratified by age, sex, education and body mass index. Beta regression analyses were conducted to estimate the effect of multiple risk factors on the HUWs.ResultsIn total, 55 882 individuals were included in the analysis. The overall mean HUW was 0.764. The mean HUW of healthy individuals was 0.768, 0.759 for those with IFG, 0.746 for those with IGT, 0.745 for those with IFG&IGT, and 0.738 for those with T2D. In the overall model, all variables except underweight vs. normal weight were significantly associated with HUW. Younger age, male sex, and higher education were associated with increased HUW. Normal weight, or being overweight was associated with elevated HUW, while obesity was associated with lower HUW.ConclusionsHealthy individuals had higher HUWs than participants with T2D, while individuals with IFG, IGT or IFG&IGT had HUWs that ranged between those for NGT and T2D. Therefore, preventing the development of pre-diabetic states would improve health-related quality of life in addition to lowering the risk of developing T2D.