International Agency for Research on Cancer

About: International Agency for Research on Cancer is a government organization based out in Lyon, France. It is known for research contribution in the topics: Cancer & Population. The organization has 2989 authors who have published 9010 publications receiving 929752 citations. The organization is also known as: IARC.

Tobacco smoking-associated genome-wide DNA methylation changes in the EPIC study

Abstract: Aim: Epigenetic changes may occur in response to environmental stressors, and an altered epigenome pattern may represent a stable signature of environmental exposure. Materials & methods: Here, we examined the potential of DNA methylation changes in 910 prediagnostic peripheral blood samples as a marker of exposure to tobacco smoke in a large multinational cohort. Results: We identified 748 CpG sites that were differentially methylated between smokers and nonsmokers, among which we identified novel regionally clustered CpGs associated with active smoking. Importantly, we found a marked reversibility of methylation changes after smoking cessation, although specific genes remained differentially methylated up to 22 years after cessation. Conclusion: Our study has comprehensively cataloged the smoking-associated DNA methylation alterations and showed that these alterations are reversible after smoking cessation.

Databases on food phytochemicals and their health-promoting effects.

Abstract: Considerable information on the chemistry and biological properties of dietary phytochemicals has accumulated over the past three decades. The scattering of the data in tens of thousands publications and the diversity of experimental approaches and reporting formats all make the exploitation of this information very difficult. Some of the data have been collected and stored in electronic databases so that they can be automatically updated and retrieved. These databases will be particularly important in the evaluation of the effects on health of phytochemicals and in facilitating the exploitation of nutrigenomic data. The content of over 50 databases on chemical structures, spectra, metabolic pathways in plants, occurrence and concentrations in foods, metabolism in humans and animals, biological properties, and effects on health or surrogate markers of health is reviewed. Limits of these databases are emphasized, and needs and recommendations for future developments are underscored. More investments in the construction of databases on phytochemicals and their effects on health are clearly needed. They should greatly contribute to the success of future research in this field.

Smoking and human papillomavirus infection: pooled analysis of the International Agency for Research on Cancer HPV Prevalence Surveys

Abstract: Smoking increases the risk of squamous-cell carcinoma of the cervix but it is not clear whether smoking increases the risk of acquisition or persistence of human papillomavirus (HPV) infection. Information on smoking was collected from 10 areas in four continents among population-based age-stratified random samples of women aged 15 years or older. HPV testing was performed using PCR-based enzyme immunoassay. Unconditional logistic regression was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) of being HPV-positive by smoking habits adjusted for age and lifetime number of sexual partners. Ten thousand five hundred and seventy-seven women (mean age 41.4 years) were included. Among current smokers the risk of being HPV-positive increased with smoking intensity after allowing for lifetime number of sexual partners: ORs for less than 5 5-14 and greater than or equal to 15 cigarettes per day were 1.21 (95% CI 0.95-1.54) 1.39 (95% CI 1.04-1.87) and 2.01 (95% CI 1.32-3.08) respectively as compared with never-smokers. The risk among former smokers (OR = 0.95 95% CI 0.73-1.23) was similar to that among never-smokers. Analyses stratified by lifetime number of sexual partners showed a significant trend in risk only for women with one lifetime sexual partner. Our study suggests that current though not former smoking is associated with an increased prevalence of HPV after allowance for sexual covariates. Among current smokers HPV prevalence increased with smoking intensity but a clear dose-response relationship was exclusively seen among women who declared one lifetime sexual partner. (authors)

Genetic evidence and integration of various data sources for classifying uncertain variants into a single model

Abstract: Genetic testing often results in the finding of a variant whose clinical significance is unknown. A number of different approaches have been employed in the attempt to classify such variants. For some variants, case-control, segregation, family history, or other statistical studies can provide strong evidence of direct association with cancer risk. For most variants, other evidence is available that relates to properties of the protein or gene sequence. In this work we propose a Bayesian method for assessing the likelihood that a variant is pathogenic. We discuss the assessment of prior probability, and how to combine the various sources of data into a statistically valid integrated assessment with a posterior probability of pathogenicity. In particular, we propose the use of a two-component mixture model to integrate these various sources of data and to estimate the parameters related to sensitivity and specificity of specific kinds of evidence. Further, we discuss some of the issues involved in this process and the assumptions that underpin many of the methods used in the evaluation process.

Pilot phase studies on the accuracy of dietary intake measurements in the EPIC project: Overall evaluation of results

Abstract: Background. As part of the European Prospective Investigation into Cancer and Nutrition (EPIC), preliminary studies were conducted to evaluate the accuracy of individuals' dietary intake measurements from newly developed questionnaires. Methods. In six countries that adhered from the very beginning to the multicentre, co-ordinated EPIC project, the validity studies were based on two repeat questionnaire measurements at the start and at the end of a 1-year period, in groups of about 100 volunteers of both sexes. In addition, during this year, up to 12 24-hour recalls per person were taken monthly, and up to four blood and urine specimens were collected for measurement of biochemical markers. In three countries that joined EPIC later, the designs of the validity studies and type of 'reference' measurement chosen were somewhat different. The results presented in this overview paper are taken partly from more detailed, country-specific publications, and partly from a central (re-)analysis of the original data, to ensure a uniform approach to the statistical analyses and presentation. Results. Averaged over subgroups by country and gender, Spearman coefficients of correlation between questionnaire measurements and the individuals' average 24-hour recalls ranged from 0.37 for fish to 0.68 for dairy products and 0.79 for alcoholic beverages. For energy-adjusted nutrient intakes (or nutrient densities, in the UK), mean Pearson correlation coefficients, corrected for residual attenuation due to day-to-day variations in the 24-hour recalls in all but two countries, ranged from 0.37 for retinol and 0.48 for vitamin E to 0.60 for carbohydrates and 0.12 for total alcohol intake. Correlations between energy-adjusted nutrient intakes and biochemical markers on average were low, but varied considerably between study centres. Conclusions. On average, most estimated correlation coefficients were of similar magnitude to those observed by independent research groups. The role of the preliminary validity studies, and various benefits drawn from these studies for further planning of the EPIC project are discussed.