Cancer mortality in chrysotile miners and millers, Russian Federation: main results (Asbest Chrysotile Cohort-Study).

BACKGROUND: We investigated mortality in workers of the world's largest chrysotile mine and enrichment factories located in the town of Asbest, Russian Federation. METHODS: This historical cohort study included all workers employed for at least 1 year between 1975 and 2010 and follow-up until the end of 2015. Cumulative exposure to dust was estimated based on workers' complete occupational history linked to dust measurements systematically collected from the 1950s. Exposure to chrysotile fibers was estimated using dust-to-fiber conversion factors. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated as mortality rate ratios in Poisson regression models. RESULTS: A total of 30 445 (32% women) workers accumulated 721 312 person-years at risk and 11 110 (36%) died. Of the workers, 54% had more than 30 years since their first exposure. We found an exposure-response between cumulative dust and lung cancer mortality in men. No clear association with dust exposure but a modest increase in the highest category of fiber exposure was seen for lung cancer in women. Mesothelioma mortality was increased (RR = 7.64, 95% CI = 1.18 to 49.5, to at least 80 fibers per cm3 years and RR = 4.56, 95% CI = 0.94 to 22.1, to at least 150 mg/m3 years [dust]), based on 13 deaths. For colorectal and stomach cancer, there were inconsistent associations. No associations were seen for laryngeal or ovarian cancer. CONCLUSION: In this large-scale epidemiological study in the world's largest active asbestos mine, we confirmed an increased risk of mesothelioma with high fiber exposure and an increasing mortality for lung cancer in men with increasing dust exposure. Less clear-cut increased lung cancer mortality was seen in the women. Continued mortality follow-up is warranted.

Risk of hematological malignancies from CT radiation exposure in children, adolescents and young adults.

Over one million European children undergo computed tomography (CT) scans annually. Although moderate- to high-dose ionizing radiation exposure is an established risk factor for hematological malignancies, risks at CT examination dose levels remain uncertain. Here we followed up a multinational cohort (EPI-CT) of 948,174 individuals who underwent CT examinations before age 22 years in nine European countries. Radiation doses to the active bone marrow were estimated on the basis of body part scanned, patient characteristics, time period and inferred CT technical parameters. We found an association between cumulative dose and risk of all hematological malignancies, with an excess relative risk of 1.96 (95% confidence interval 1.10 to 3.12) per 100 mGy (790 cases). Similar estimates were obtained for lymphoid and myeloid malignancies. Results suggest that for every 10,000 children examined today (mean dose 8 mGy), 1-2 persons are expected to develop a hematological malignancy attributable to radiation exposure in the subsequent 12 years. Our results strengthen the body of evidence of increased cancer risk at low radiation doses and highlight the need for continued justification of pediatric CT examinations and optimization of doses.

Exposure to pesticides and risk of Hodgkin lymphoma in an international consortium of agricultural cohorts (AGRICOH).

PURPOSE: Some pesticides may increase the risk of certain lymphoid malignancies, but few studies have examined Hodgkin lymphoma (HL). In this exploratory study, we examined associations between agricultural use of 22 individual active ingredients and 13 chemical groups and HL incidence. METHODS: We used data from three agricultural cohorts participating in the AGRICOH consortium: the French Agriculture and Cancer Cohort (2005-2009), Cancer in the Norwegian Agricultural Population (1993-2011), and the US Agricultural Health Study (1993-2011). Lifetime pesticide use was estimated from crop-exposure matrices or self-report. Cohort-specific covariate-adjusted overall and age-specific (< 40 or ≥ 40 years) hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression and combined using random effects meta-analysis. RESULTS: Among 316 270 farmers (75% male) accumulating 3 574 815 person-years at risk, 91 incident cases of HL occurred. We did not observe statistically significant associations for any of the active ingredients or chemical groups studied. The highest risks of HL overall were observed for the pyrethroids deltamethrin (meta-HR = 1.86, 95% CI 0.76-4.52) and esfenvalerate (1.86, 0.78-4.43), and inverse associations of similar magnitude were observed for parathion and glyphosate. Risk of HL at ≥ 40 years of age was highest for ever-use of dicamba (2.04, 0.93-4.50) and lowest for glyphosate (0.46, 0.20-1.07). CONCLUSION: We report the largest prospective investigation of these associations. Nonetheless, low statistical power, a mixture of histological subtypes and a lack of information on tumour EBV status complicate the interpretability of the results. Most HL cases occurred at older ages, thus we could not explore associations with adolescent or young adult HL. Furthermore, estimates may be attenuated due to non-differential exposure misclassification. Future work should aim to extend follow-up and refine both exposure and outcome classification.

Cancer incidence in agricultural workers: Findings from an international consortium of agricultural cohort studies (AGRICOH).

BACKGROUND: Agricultural work can expose workers to potentially hazardous agents including known and suspected carcinogens. This study aimed to evaluate cancer incidence in male and female agricultural workers in an international consortium, AGRICOH, relative to their respective general populations. METHODS: The analysis included eight cohorts that were linked to their respective cancer registries: France (AGRICAN: n = 128,101), the US (AHS: n = 51,165, MESA: n = 2,177), Norway (CNAP: n = 43,834), Australia (2 cohorts combined, Australian Pesticide Exposed Workers: n = 12,215 and Victorian Grain Farmers: n = 919), Republic of Korea (KMCC: n = 8,432), and Denmark (SUS: n = 1,899). For various cancer sites and all cancers combined, standardized incidence ratios (SIR) and 95% confidence intervals (CIs) were calculated for each cohort using national or regional rates as reference rates and were combined by random-effects meta-analysis. RESULTS: During nearly 2,800,000 person-years, a total of 23,188 cancers were observed. Elevated risks were observed for melanoma of the skin (number of cohorts = 3, meta-SIR = 1.18, CI: 1.01-1.38) and multiple myeloma (n = 4, meta-SIR = 1.27, CI: 1.04-1.54) in women and prostate cancer (n = 6, meta-SIR = 1.06, CI: 1.01-1.12), compared to the general population. In contrast, a deficit was observed for the incidence of several cancers, including cancers of the bladder, breast (female), colorectum, esophagus, larynx, lung, and pancreas and all cancers combined (n = 7, meta-SIR for all cancers combined = 0.83, 95% CI: 0.77-0.90). The direction of risk was largely consistent across cohorts although we observed large between-cohort variations in SIR for cancers of the liver and lung in men and women, and stomach, colorectum, and skin in men. CONCLUSION: The results suggest that agricultural workers have a lower risk of various cancers and an elevated risk of prostate cancer, multiple myeloma (female), and melanoma of skin (female) compared to the general population. Those differences and the between-cohort variations may be due to underlying differences in risk factors and warrant further investigation of agricultural exposures.

Dose Estimation for the European Epidemiological Study on Pediatric Computed Tomography (EPI-CT).

Within the European Epidemiological Study to Quantify Risks for Paediatric Computerized Tomography (EPI-CT study), a cohort was assembled comprising nearly one million children, adolescents and young adults who received over 1.4 million computed tomography (CT) examinations before 22 years of age in nine European countries from the late 1970s to 2014. Here we describe the methods used for, and the results of, organ dose estimations from CT scanning for the EPI-CT cohort members. Data on CT machine settings were obtained from national surveys, questionnaire data, and the Digital Imaging and Communications in Medicine (DICOM) headers of 437,249 individual CT scans. Exposure characteristics were reconstructed for patients within specific age groups who received scans of the same body region, based on categories of machines with common technology used over the time period in each of the 276 participating hospitals. A carefully designed method for assessing uncertainty combined with the National Cancer Institute Dosimetry System for CT (NCICT, a CT organ dose calculator), was employed to estimate absorbed dose to individual organs for each CT scan received. The two-dimensional Monte Carlo sampling method, which maintains a separation of shared and unshared error, allowed us to characterize uncertainty both on individual doses as well as for the entire cohort dose distribution. Provided here are summaries of estimated doses from CT imaging per scan and per examination, as well as the overall distribution of estimated doses in the cohort. Doses are provided for five selected tissues (active bone marrow, brain, eye lens, thyroid and female breasts), by body region (i.e., head, chest, abdomen/pelvis), patient age, and time period (1977-1990, 1991-2000, 2001-2014). Relatively high doses were received by the brain from head CTs in the early 1990s, with individual mean doses (mean of 200 simulated values) of up to 66 mGy per scan. Optimization strategies implemented since the late 1990s have resulted in an overall decrease in doses over time, especially at young ages. In chest CTs, active bone marrow doses dropped from over 15 mGy prior to 1991 to approximately 5 mGy per scan after 2001. Our findings illustrate patterns of age-specific doses and their temporal changes, and provide suitable dose estimates for radiation-induced risk estimation in epidemiological studies.

Age at start of using tobacco on the risk of head and neck cancer: Pooled analysis in the International Head and Neck Cancer Epidemiology Consortium (INHANCE).

BACKGROUND: Tobacco use is a well-established risk factor for head and neck cancer (HNC). However, less is known about the potential impact of exposure to tobacco at an early age on HNC risk. METHODS: We analyzed individual-level data on ever tobacco smokers from 27 case-control studies (17,146 HNC cases and 17,449 controls) in the International Head and Neck Cancer Epidemiology (INHANCE) consortium. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using random-effects logistic regression models. RESULTS: Without adjusting for tobacco packyears, we observed that younger age at starting tobacco use was associated with an increased HNC risk for ever smokers (OR<10 years vs. ≥30 years: 1.64, 95% CI: 1.35, 1.97). However, the observed association between age at starting tobacco use and HNC risk became null after adjusting for tobacco packyears (OR<10 years vs. ≥30 years: 0.97, 95% CI: 0.80, 1.19). In the stratified analyses on HNC subsites by tobacco packyears or years since quitting, no difference in the association between age at start and HNC risk was observed. CONCLUSIONS: Results from this pooled analysis suggest that increased HNC risks observed with earlier age at starting tobacco smoking are largely due to longer duration and higher cumulative tobacco exposures.

Prevalence of human papillomavirus and Helicobacter pylori in esophageal and gastroesophageal junction cancer biopsies from a case-control study in Ethiopia.

BACKGROUND: Ethiopia lies in the high-risk corridor of esophageal squamous cell carcinoma in East Africa, where individuals with this malignancy often do not report established risk factors, suggesting unidentified etiologies. Here, we report the prevalence of mucosal human papillomavirus (HPV) and of Helicobacter pylori (H. pylori) detection in endoscopy-obtained esophageal and gastroesophageal junction biopsies and in oral cell specimens taken at the time of esophageal cancer diagnosis in a case-control study in Addis Ababa, Ethiopia. METHODS: DNA extraction was performed from fresh frozen tissue and oral cell pellets obtained with saline solution gargling subsequently fixed with ethanol. Mucosal HPV and H. pylori DNA was detected using highly sensitive assays that combine multiplex polymerase chain reaction and bead-based Luminex technology. The proportions of specimens testing positive were expressed as percentages, with binomial 95% confidence intervals. Agreement of results between tissue biopsy and oral cell specimens was estimated using the kappa statistic. Comparison of study participants' characteristics by test results was done using the Pearson chi-square test. RESULTS: HPV DNA was detected in 1 of 62 tumor specimens (2, 95% confidence interval (CI): 0-9%), corresponding to HPV16 type. HPV DNA was detected in the oral cavity of 7 cases (11, 95% CI: 5-22%) and 4 of 56 matched healthy controls (7, 95% CI: 2-17%), with multiple HPV types detected. Detection of H. pylori DNA was 55% (95% CI: 42-68%), and 20 of 34 H. pylori-positive specimens (59, 95% CI: 41-75%) were positive for the cagA gene. Agreement of detection rates between tissue and oral cells in cases was poor for HPV and for H. pylori. CONCLUSIONS: The prevalence of mucosal-type HPV was very low, whereas H. pylori was more commonly detected, with a high proportion testing positive for the pro-inflammatory gene cagA. These novel findings remain to be replicated in larger studies and with the addition of serological determinations to better understand their biological significance in the context of esophageal and gastroesophageal junction cancers.

Animal farming and the risk of lymphohaematopoietic cancers: a meta-analysis of three cohort studies within the AGRICOH consortium.

OBJECTIVE: Animal farming entails a variety of potential exposures, including infectious agents, endotoxins and pesticides, which may play a role in the aetiology of lymphohaematopoietic cancers (LHCs). The aim of this study was to assess whether farming specific animal species is associated with the risk of overall LHC or its subtypes. METHODS: Data from three prospective cohort studies in the USA, France and Norway which are part of the Agricultural Cohort consortium and which collected information about animal farming and cancer were used. Analyses included 316 270 farmers and farm workers. Adjusted Cox models were used to investigate the associations of 13 histological subtypes of LHC (n=3282) with self-reported livestock (cattle, pigs and sheep/goats) and poultry (ever/never and numbers raised) farming. Cohort-specific HRs were combined using random-effects meta-analysis. RESULTS: Ever animal farming in general or farming specific animal species was not meta-associated with overall LHC. The risk of myeloid malignancies decreased with increasing number of livestock (p trend=0.01). Increased risk of myeloproliferative neoplasms was seen with increasing number of sheep/goats (p trend <0.01), while a decreased risk was seen with increasing number of livestock (p trend=0.02). Between cohorts, we observed heterogeneity in the association of type of animal farmed and various LHC subtypes. CONCLUSIONS: This large-scale study of three prospective agricultural cohorts showed no association between animal farming and LHC risk, but few associations between specific animal species and LHC subtypes were observed. The observed differences in associations by countries warrant further investigations.

Pesticide use and risk of non-Hodgkin lymphoid malignancies in agricultural cohorts from France, Norway and the USA: a pooled analysis from the AGRICOH consortium.

BACKGROUND: Pesticides are commonly used in agriculture, and previous studies endorsed the need to further investigate the possible association between their use and risk of lymphoid malignancies in agricultural workers. METHODS: We investigated the relationship of ever use of 14 selected pesticide chemical groups and 33 individual active chemical ingredients with non-Hodgkin lymphoid malignancies (NHL) overall or major subtypes, in a pooled analysis of three large agricultural worker cohorts. Pesticide use was derived from self-reported history of crops cultivated combined with crop-exposure matrices (France and Norway) or self-reported lifetime use of active ingredients (USA). Cox regression models were used to estimate cohort-specific hazard ratios (HRs) and 95% confidence intervals (CIs), which were combined using random effects meta-analysis to calculate meta-HRs. RESULTS: During follow-up, 2430 NHL cases were diagnosed in 316 270 farmers accruing 3 574 815 person-years under risk. Most meta-HRs suggested no association. Moderately elevated meta-HRs were seen for: NHL and ever use of terbufos (meta-HR = 1.18, 95% CI: 1.00-1.39); chronic lymphocytic leukaemia/small lymphocytic lymphoma and deltamethrin (1.48, 1.06-2.07); and diffuse large B-cell lymphoma and glyphosate (1.36, 1.00-1.85); as well as inverse associations of NHL with the broader groups of organochlorine insecticides (0.86, 0.74-0.99) and phenoxy herbicides (0.81, 0.67-0.98), but not with active ingredients within these groups, after adjusting for exposure to other pesticides. CONCLUSIONS: Associations of pesticides with NHL appear to be subtype- and chemical-specific. Non-differential exposure misclassification was an important limitation, showing the need for refinement of exposure estimates and exposure-response analyses.

Qat use and esophageal cancer in Ethiopia: A pilot case-control study.

BACKGROUND: Qat (Catha edulis) chewing is reported to induce lesions in the buccal mucosa, irritation of the esophagus, and esophageal reflux. Case series suggest a possible etiological role in oral and esophageal cancers. This pilot study aimed to generate preliminary estimates of the magnitude and direction of the association between qat use and esophageal cancer (EC) risk and to inform the logistics required to conduct a multi-center case-control study. METHODS: Between May 2012 and May 2013, 73 EC cases (including 12 gastro-esophageal junction cases) and 133 controls matched individually on sex, age, and residence were enrolled at two endoscopy clinics and a cancer treatment hospital in Addis Ababa. A face-to-face structured questionnaire was administered. Qat use was defined as ever having chewed qat once a week or more frequently for at least one year. Odds ratios were calculated using conditional logistic regression. RESULTS: Only 8% of cases resided in Addis Ababa. Qat use was more frequent in cases (36%) than in controls (26%). A 2-fold elevation in EC risk was observed in ever qat chewers compared with never users in unadjusted conditional logistic regression (OR = 2.12; 95% CI = 0.94, 4.74), an association that disappeared after adjusting for differences in tobacco use, consumption of alcohol and green vegetables, education level, and religion (OR = 0.95; 0.22, 4.22). Among never tobacco users, however, a non-significant increase in EC risk was suggested in ever qat users also after adjustment. Increases in EC risk were observed with ever tobacco use, alcohol consumption, low consumption of green vegetables, a salty diet, illiteracy, and among Muslims; the four latter associations were significant. CONCLUSIONS: This pilot study generated EC risk estimates in association with a habit practiced by millions of people and never before studied in a case-control design. Results must be interpreted cautiously in light of possible selection bias, with some demographics such as education level and religion differing between cases and controls. A large case-control study with enrolment of EC cases and carefully matched controls at health facilities from high-risk areas in the countryside, where the majority of cases occur, is needed to further investigate the association between qat use and EC.

Survival From Childhood Hematological Malignancies in Denmark: Is Survival Related to Family Characteristics?

BACKGROUND: Due to diverse findings as to the role of family factors for childhood cancer survival even within Europe, we explored a nationwide, register-based cohort of Danish children with hematological malignancies. METHODS: All children born between 1973 and 2006 and diagnosed with a hematological malignancy before the age of 20 years (N = 1,819) were followed until 10 years from diagnosis. Kaplan-Meier curves and Cox proportional hazards models estimating hazard ratios (HR) and 95% confidence intervals (CI) were used to assess the impact of family characteristics on overall survival in children with hematological malignancies. RESULTS: Having siblings and increasing birth order were associated with reduced survival from acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Associations with AML were strongest and statistically significant. HRs of 1.62 (CI 0.85; 3.09) and 5.76 (CI 2.01; 16.51) were observed for the fourth or later born children with ALL (N = 41) and AML (N = 9), respectively. Children with older parents showed a tendency toward inferior ALL survival, while for AML young maternal age was related to poorer survival. Based on small numbers, a trend toward poorer survival from non-Hodgkin lymphoma was observed for children having siblings and for children of younger parents. CONCLUSIONS: Further research is warranted to gain further knowledge on the impact of family factors on childhood cancer survival in other populations and to elaborate potential underlying mechanisms and pathways of those survival inequalities.

Assessment of occupational exposure to pesticides in a pooled analysis of agricultural cohorts within the AGRICOH consortium.

BACKGROUND: This paper describes methods developed to assess occupational exposure to pesticide active ingredients and chemical groups, harmonised across cohort studies included in the first AGRICOH pooling project, focused on the risk of lymph-haematological malignancies. METHODS: Three prospective agricultural cohort studies were included: US Agricultural Health Study (AHS), French Agriculture and Cancer Study (AGRICAN) and Cancer in the Norwegian Agricultural Population (CNAP). Self-reported pesticide use was collected in AHS. Crop-exposure matrices (CEMs) were developed for AGRICAN and CNAP. We explored the potential impact of these differences in exposure assessment by comparing a CEM approach estimating exposure in AHS with self-reported pesticide use. RESULTS: In AHS, 99% of participants were considered exposed to pesticides, 68% in AGRICAN and 63% in CNAP. For all cohorts combined (n=316 270), prevalence of exposure ranged from 19% to 59% for 14 chemical groups examined, and from 13% to 46% for 33 active ingredients. Exposures were highly correlated within AGRICAN and CNAP where CEMs were applied; they were less correlated in AHS. Poor agreement was found between self-reported pesticide use and assigned exposure in AHS using a CEM approach resembling the assessment for AGRICAN (κ -0.00 to 0.33) and CNAP (κ -0.01 to 0.14). CONCLUSIONS: We developed country-specific CEMs to assign occupational exposure to pesticides in cohorts lacking self-reported data on the use of specific pesticides. The different exposure assessment methods applied may overestimate or underestimate actual exposure prevalence, and additional work is needed to better estimate how far the exposure estimates deviate from reality.

Birth order and risk of childhood cancer in the Danish birth cohort of 1973-2010.

PURPOSE: Many studies have investigated the possible association between birth order and risk of childhood cancer, although the evidence to date has been inconsistent. Birth order has been used as a marker for various in utero or childhood exposures and is relatively straightforward to assess. METHODS: Data were obtained on all children born in Denmark between 1973 and 2010, involving almost 2.5 million births and about 5,700 newly diagnosed childhood cancers before the age of 20 years. Data were analyzed using Poisson regression models. RESULTS: We failed to observe associations between birth order and risk of any childhood cancer subtype, including acute lymphoblastic leukemia; all rate ratios were close to one. Further analyses stratified by birth cohort (those born between 1973 and 1990, and those born between 1991 and 2010) also failed to show any associations. Considering stillbirths and/or controlling for birth weight and parental age in the analyses had no effect on the results. Analyses by years of birth (those born between 1973 and 1990, and those born between 1991 and 2010) did not show any changes in the overall pattern of no association. CONCLUSIONS: In this large cohort of all children born in Denmark over an almost 40-year period, we did not observe an association between birth order and the risk of childhood cancer.

Does a more refined assessment of exposure to bitumen fume and confounders alter risk estimates from a nested case-control study of lung cancer among European asphalt workers?

OBJECTIVE: To investigate whether a refined assessment of exposure to bitumen fume among workers in the European asphalt industry within a nested case-control study resulted in a different interpretation pertaining to risk of lung cancer mortality compared with the cohort study. METHODS: Pearson correlation coefficients between refined and original estimates were calculated. Logistic regression and generalised additive models (penalised splines) were fitted to estimate ORs for exposure to bitumen fume using the refined and original exposure estimates, respectively, while adjusting for potential confounding. RESULTS: 1555 subjects included in the nested case-control study had both refined and original estimates for exposure to bitumen fume. Exposure assessment in the nested case-control study (compared with the cohort phase) increased the number of subjects never-exposed to bitumen fume from 18% to 32%. From the 1282 subjects originally considered exposed in the cohort phase, 309 (24%) became unexposed after the nested case-control exposure assessment. From the 273 subjects originally considered non-exposed in the cohort phase, 87 (32%) became exposed in the nested case-control study. The majority (75%) of subjects however did not change exposure status and changes were similar among cases and controls. Correlation coefficients between refined and original exposure estimates were moderate overall (range 0.42-0.46), but varied considerably among countries. The ORs and exposure-response curves for exposure to bitumen fume were not meaningfully different between analyses that used refined and original exposure estimates. Adjustment for tobacco smoking and exposure to coal tar did not change these patterns. CONCLUSIONS: Our results showed that more detailed data collection and exposure assessment in the nested case-control study compared with the cohort study did change exposure status of many subjects, but did not alter results of the exposure-response analysis. Adjustment for tobacco smoking did not have a noticeable effect on risk estimates either.

Association between HBX status, aflatoxin-induced R249S TP53 mutation and risk of hepatocellular carcinoma in a case-control study from Thailand.

Hepatocellular carcinoma (HCC) is associated with hepatitis B virus (HBV) chronicity and dietary exposure to aflatoxin, a mutagen targeting codon 249 of tumor suppressor TP53 (R249S mutation). Based on a case-control in Thailand, we have measured R249S and the status of HBX gene in plasma DNA of 176 cases and 133 referents. Detection of HBX complete sequences was associated with R249S in HCC with no documented prior cirrhosis but not in HCC developing in a context of cirrhosis or in non-cancer chronic liver diseases. Thus, R249S may specifically cooperate with HBX in a pathway to HCC that bypasses cirrhosis.

TP53 R249S mutation, genetic variations in HBX and risk of hepatocellular carcinoma in The Gambia.

In regions with high prevalence of chronic hepatitis B virus (HBV) infection and dietary aflatoxin B(1) (AFB(1)) exposure, hepatocellular carcinomas (HCCs) often contain TP53 mutation at codon 249 (R249S). Furthermore, a C-terminal truncated HBx protein expressed from hepatocyte integrated HBV is associated with HCC development. This study evaluates the association between R249S and HBX status in relation to HCC in West African population. HBX (complete or 3'-truncated) and HBS genes were assessed by PCR in cell-free DNA (CFDNA) from plasma of subjects recruited in a hospital-based case-control study (325 controls, 78 cirrhotic patients and 198 HCC cases) conducted in The Gambia. These samples had been previously analyzed for R249S and HBV serological status. Complete HBX sequence was frequently detected in CFDNA of HCC-R249S positive (77%, 43/56) compared with HCC-R249S-negative cases (44%, 22/50). Conversely, the proportion of 3'-truncated HBX gene was significantly higher in HCC-R249S negative than positive cases (34%, 17/50, compared with 12%, 7/56) (χ(2) = 12.12; P = 0.002; distribution of R249S negative and positive according to HBX status). Occult HBV infection (detected by PCR) was present in 24% of HCC previously considered as negative by HBV serology. Moreover, HBV mutation analysis revealed that double mutation at nucleotides 1762(T)/1764(A) was associated with diagnosis of cirrhosis or HCC {cirrhosis: odds ratio (OR): 9.50 [95% confidence interval (CI) 1.50-60.11]; HCC: OR: 11.29 [95% CI 2.07-61.47]}. These findings suggest that in HCC from The Gambia, complete HBX sequences are often associated with the presence of TP53 R249S mutation.

Sources of pre-analytical variations in yield of DNA extracted from blood samples: analysis of 50,000 DNA samples in EPIC.

The European Prospective Investigation into Cancer and nutrition (EPIC) is a long-term, multi-centric prospective study in Europe investigating the relationships between cancer and nutrition. This study has served as a basis for a number of Genome-Wide Association Studies (GWAS) and other types of genetic analyses. Over a period of 5 years, 52,256 EPIC DNA samples have been extracted using an automated DNA extraction platform. Here we have evaluated the pre-analytical factors affecting DNA yield, including anthropometric, epidemiological and technical factors such as center of subject recruitment, age, gender, body-mass index, disease case or control status, tobacco consumption, number of aliquots of buffy coat used for DNA extraction, extraction machine or procedure, DNA quantification method, degree of haemolysis and variations in the timing of sample processing. We show that the largest significant variations in DNA yield were observed with degree of haemolysis and with center of subject recruitment. Age, gender, body-mass index, cancer case or control status and tobacco consumption also significantly impacted DNA yield. Feedback from laboratories which have analyzed DNA with different SNP genotyping technologies demonstrate that the vast majority of samples (approximately 88%) performed adequately in different types of assays. To our knowledge this study is the largest to date to evaluate the sources of pre-analytical variations in DNA extracted from peripheral leucocytes. The results provide a strong evidence-based rationale for standardized recommendations on blood collection and processing protocols for large-scale genetic studies.

Second primary malignancies among women with uterine sarcoma.

OBJECTIVE: Uterine sarcomas (US) are rare malignancies with unclear aetiology. Studies on uterine sarcomas in the setting of second primary malignant tumours can provide clues to aetiology and identify side effects of different treatments. METHODS: A cohort of 8606 cases of US was extracted from the data from 13 cancer registries and followed for second primary cancers within the period 1943-2000. Standardized incidence ratios (SIRs) were calculated, and Poisson regression analyses were performed. RESULTS: There were 499 cancer cases observed after a first diagnosis of US (SIR 1.26, 95%CI 1.16-1.38). SIRs were elevated for cancers of the mouth and pharynx (2.16, 95%CI 1.15-3.69), colorectum (1.60, 95%CI 1.28-1.98), lung (1.73, 95%CI 1.27-2.29), breast (1.25, 95%CI 1.05-1.49), urinary bladder (1.74, 95%CI 1.02-2.79), kidney (2.00, 95%CI 1. 24-3.06), thyroid gland (2.74, 95%CI 1.42-4.79), and soft tissue sarcoma (5.23, 95%CI 2.51-9.62). The risk of breast cancer increased along with increasing age of US diagnosis (p trend 0.040). The risk of kidney cancer increased along with decreasing age of US diagnosis (p trend 0.004) and short time since the US diagnosis (p trend 0.018). CONCLUSIONS: Our study demonstrated increased risk of certain cancers following a diagnosis of US. The elevated risk for breast cancer may indicate shared hormonal aetiology, while the increased risk of colorectal and bladder cancers after US may be caused by radiation therapy of US. The clustering of smoking-related cancers after US is worth exploring in the future.

DNA methylation changes associated with risk factors in tumors of the upper aerodigestive tract.

Cancers of the upper aerodigestive tract (UADT) are common forms of malignancy associated with tobacco and alcohol exposures, although human papillomavirus and nutritional deficiency are also important risk factors. While somatically acquired DNA methylation changes have been associated with UADT cancers, what triggers these events and precise epigenetic targets are poorly understood. In this study, we applied quantitative profiling of DNA methylation states in a panel of cancer-associated genes to a case-control study of UADT cancers. Our analyses revealed a high frequency of aberrant hypermethylation of several genes, including MYOD1, CHRNA3 and MTHFR in UADT tumors, whereas CDKN2A was moderately hypermethylated. Among differentially methylated genes, we identified a new gene (the nicotinic acetycholine receptor gene) as target of aberrant hypermethylation in UADT cancers, suggesting that epigenetic deregulation of nicotinic acetycholine receptors in non-neuronal tissues may promote the development of UADT cancers. Importantly, we found that sex and age is strongly associated with the methylation states, whereas tobacco smoking and alcohol intake may also influence the methylation levels in specific genes. This study identifies aberrant DNA methylation patterns in UADT cancers and suggests a potential mechanism by which environmental factors may deregulate key cellular genes involved in tumor suppression and contribute to UADT cancers.