Arsenicals in agriculture. Beginning in the 1970s, the use of arsenic compounds for such purposes as wood preservatives, began to grow. By 1980, in the USA, 70% of arsenic had been consumed for the ...production of wood preservatives. This practice was later stopped, due to the US Environmental Protection Agency (EPA) ban of the arsenic-and chromium-based wood preservative chromated copper arsenate. In the past, arsenical herbicides containing cacodylic acid as an active ingredient have been used extensively in the USA, from golf courses to cotton fields, and drying-out the plants before harvesting. The original commercial form of Agent Blue was among 10 toxic insecticides, fungicides and herbicides partially deregulated by the US EPA in February 2004, and specific limits on toxic residues in meat, milk, poultry and eggs, were removed. Today, however, they are no longer used as weed-killers, with one exception - monosodium methanearsonate (MSMA), a broadleaf weed herbicide for use on cotton. Severe poisonings from cacodylic acid caused headache, dizziness, vomiting, profuse and watery diarrhea, followed by dehydration, gradual fall in blood pressure, stupor, convulsions, general paralysis and possible risk of death within 3-14 days.The relatively frequent use of arsenic and its compounds in both industry and agriculture points to a wide spectrum of opportunities for human exposure. This exposure can be via inhalation of airborne arsenic, contaminated drinking water, beverages, or from food and drugs. Today, acute organic arsenical poisonings are mostly accidental. Considerable concern has developed surrounding its delayed effects, for its genotoxic and carcinogenic potential, which has been demonstrated in epidemiological studies and subsequent animal experiments.
There is substantial epidemiological evidence for an excessive risk, mostly for skin and lung cancer, among humans exposed to organic arsenicals in occupational and environmental settings. Furthermore, the genotoxic and carcinogenic effects have only been observed at relatively high exposure rates. Current epidemiological and experimental studies are attempting to elucidate the mechanism of this action, pointing to the question whether arsenic is actually a true genotoxic, or rather an epigenetic carcinogen. Due to the complexity of its effects, both options remain plausible. Its interactions with other toxic substances still represent another important field of interest.
Purpose: To provide a comprehensive, thorough analysis of somatic mutation and promoter hypermethylation of the von Hippel-Lindau ( VHL ) gene in the cancer genome, unique to clear cell renal cancer ...(ccRCC). Identify relationships between the prevalence of VHL gene alterations and alteration subtypes with patient and tumor characteristics.
Experimental Design: As part of a large kidney cancer case-control study conducted in Central Europe, we analyzed VHL mutations and promoter methylation in 205 well-characterized, histologically confirmed patient tumor biopsies using a combination
of sensitive, high-throughput methods (endonuclease scanning and Sanger sequencing) and analysis of 11 CpG sites in the VHL promoter.
Results: We identified mutations in 82.4% of cases, the highest VHL gene mutation prevalence reported to date. Analysis of 11 VHL promoter CpG sites revealed that 8.3% of tumors were hypermethylated and all were mutation negative. In total, 91% of ccRCCs
exhibited alteration of the gene through genetic or epigenetic mechanisms. Analysis of patient and tumor characteristics revealed
that certain mutation subtypes were significantly associated with Fuhrman nuclear grade, metastasis, node positivity, and
self-reported family history of RCC.
Conclusion: Detection of VHL gene alterations using these accurate, sensitive, and practical methods provides evidence that the vast majority of histologically
confirmed ccRCC tumors possess genetic or epigenetic alteration of the VHL gene and support the hypothesis that VHL alteration is an early event in ccRCC carcinogenesis. These findings also indicate that VHL molecular subtypes can provide a sensitive marker of tumor heterogeneity among histologically similar ccRCC cases for etiologic,
prognostic, and translational studies.
Renal tumor heterogeneity studies have utilized the von Hippel-Lindau VHL gene to classify disease into molecularly defined subtypes to examine associations with etiologic risk factors and prognosis. ...The aim of this study was to provide a comprehensive analysis of VHL inactivation in clear cell renal tumors (ccRCC) and to evaluate relationships between VHL inactivation subgroups with renal cancer risk factors and VHL germline single nucleotide polymorphisms (SNPs). VHL genetic and epigenetic inactivation was examined among 507 sporadic RCC/470 ccRCC cases using endonuclease scanning and using bisulfite treatment and Sanger sequencing across 11 CpG sites within the VHL promoter. Case-only multivariate analyses were conducted to identify associations between alteration subtypes and risk factors. VHL inactivation, either through sequence alterations or promoter methylation in tumor DNA, was observed among 86.6% of ccRCC cases. Germline VHL SNPs and a haplotype were associated with promoter hypermethylation in tumor tissue (OR = 6.10; 95% CI: 2.28-16.35, p = 3.76E-4, p-global = 8E-5). Risk of having genetic VHL inactivation was inversely associated with smoking due to a higher proportion of wild-type ccRCC tumors former: OR = 0.70 (0.20-1.31) and current: OR = 0.56 (0.32-0.99); P-trend = 0.04. Alteration prevalence did not differ by histopathologic characteristics or occupational exposure to trichloroethylene. ccRCC cases with particular VHL germline polymorphisms were more likely to have VHL inactivation through promoter hypermethylation than through sequence alterations in tumor DNA, suggesting that the presence of these SNPs may represent an example of facilitated epigenetic variation (an inherited propensity towards epigenetic variation) in renal tissue. A proportion of tumors from current smokers lacked VHL alterations and may represent a biologically distinct clinical entity from inactivated cases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recent studies support an important role for human papillomavirus (HPV) in a subgroup of head and neck squamous cell carcinomas (HNSCC). We have evaluated the HPV deoxyribonucleic acid (DNA) ...prevalence as well as the association between serological response to HPV infection and HNSCC in two distinct populations from Central Europe (CE) and Latin America (LA).
Cases (n = 2214) and controls (n = 3319) were recruited from 1998 to 2003, using a similar protocol including questionnaire and blood sample collection. Tumour DNA from 196 fresh tissue biopsies was analysed for multiple HPV types followed by an HPV type-specific polymerase chain reaction (PCR) protocol towards the E7 gene from HPV 16. Using multiplex serology, serum samples were analysed for antibodies to 17 HPV types. Statistical analysis included the estimation of adjusted odds ratios (ORs) and the respective 95% confidence intervals (CIs).
HPV16 E7 DNA prevalence among cases was 3.1% (6/196), including 4.4% in the oropharynx (3/68), 3.8% in the hypopharynx/larynx (3/78) and 0% among 50 cases of oral cavity carcinomas. Positivity for both HPV16 E6 and E7 antibodies was associated with a very high risk of oropharyngeal cancer (OR = 179, 95% CI 35.8-899) and hypopharyngeal/laryngeal cancer (OR = 14.9, 95% CI 2.92-76.1).
A very low prevalence of HPV DNA and serum antibodies was observed among cases in both CE and LA. The proportion of head and neck cancer caused by HPV may vary substantially between different geographical regions and studies that are designed to evaluate the impact of HPV vaccination on HNSCC need to consider this heterogeneity.
Background: Domestic fuel combustion from cooking and heating is an important public health issue because roughly 3 billion people are exposed worldwide. Recently, the International Agency for ...Research on Cancer classified indoor emissions from household coal combustion as a human carcinogen (group 1) and from biomass fuel (primarily wood) as a probable human carcinogen (group 2A). Objectives: We pooled seven studies from the International Lung Cancer Consortium (5,105 cases and 6,535 controls) to provide further epidemiological evaluation of the association between in-home solid-fuel use, particularly wood, and lung cancer risk. Methods: Using questionnaire data, we classified subjects as predominant solid-fuel users (e. g., coal, wood) or nonsolid-fuel users (e.g., oil, gas, electricity). Unconditional logistic regression was used to estimate the odds ratios (ORs) and to compute 95% confidence intervals (CIs), adjusting for age, sex, education, smoking status, race/ethnicity, and study center. Results: Compared with nonsolid-fuel users, predominant coal users (OR = 1.64; 95% CI, 1.49-1.81), particularly coal users in Asia (OR = 4.93; 95% CI, 3.73-6.52), and predominant wood users in North American and European countries (OR = 1.21; 95% CI, 1.06-1.38) experienced higher risk of lung cancer. The results were similar in never-smoking women and other subgroups. Conclusions: Our results are consistent with previous observations pertaining to in-home coal use and lung cancer risk, support the hypothesis of a carcinogenic potential of in-home wood use, and point to the need for more detailed study of factors affecting these associations.
To investigate whether renal cell carcinoma (RCC) histologic subtypes possess different etiologies, we conducted analyses of established RCC risk factors by subtype (clear cell, papillary and ...chromophobe) in two case‐control studies conducted in the United States (1,217 cases, 1,235 controls) and Europe (1,097 cases, 1,476 controls). Histology was ascertained for 706 U.S. cases (58% of total) and 917 European cases (84%) through a central slide review conducted by a single pathologist. For the remaining cases, histology was ed from the original diagnostic pathology report. Case‐only analyses were performed to compute odds ratios (ORs) and 95% confidence intervals (CI) summarizing subtype differences by age, sex and race. Case‐control analyses were performed to compute subtype‐specific ORs for other risk factors using polytomous regression. In case‐only analyses, papillary cases (N = 237) were older (OR = 1.2, 95% CI = 1.1–1.4 per 10‐year increase), less likely to be female (OR = 0.5, 95% CI = 0.4–0.8) and more likely to be black (OR = 2.6, 95% CI = 1.8–3.9) as compared to clear cell cases (N = 1,524). In case‐control analyses, BMI was associated with clear cell (OR = 1.2, 95% CI = 1.1–1.3 per 5 kg/m2 increase) and chromophobe RCC (N = 80; OR = 1.2, 95% CI = 1.1–1.4), but not papillary RCC (OR = 1.1, 95% CI = 1.0–1.2; test versus clear cell, p = 0.006). No subtype differences were observed for associations with smoking, hypertension or family history of kidney cancer. Our findings support the existence of distinct age, sex and racial distributions for RCC subtypes, and suggest that the obesity‐RCC association differs by histology.
What's new?
Renal cell carcinoma (RCC) is the most common form of kidney cancer, which is the deadliest of all urologic malignancies. The present investigation aimed to better understand whether associations between RCC and established risk factors differed by RCC histologic subtype. Looking across two case‐control studies, the authors found that increasing body mass index was associated with clear cell and chromophobe RCC, but not papillary RCC. They also observed distinct age, sex, and racial distributions by subtype. The findings offer new insight into the relationship between obesity and RCC, and underscore the importance of subtype‐specific analyses when investigating RCC etiology.
Trichloroethylene (TCE) is a suspected renal carcinogen. TCE-associated renal genotoxicity occurs predominantly through glutathione S-transferase (GST) conjugation and bioactivation by renal cysteine ...beta-lyase (CCBL1). We conducted a case-control study in Central Europe (1,097 cases and 1,476 controls) specifically designed to assess risk associated with occupational exposure to TCE through analysis of detailed job histories. All jobs were coded for organic/chlorinated solvent and TCE exposure (ever/never) as well as the frequency and intensity of exposure based on detailed occupational questionnaires, specialized questionnaires, and expert assessments. Increased risk was observed among subjects ever TCE exposed odds ratio (OR) = 1.63; 95% confidence interval (95% CI), 1.04-2.54. Exposure-response trends were observed among subjects above and below the median exposure average intensity (OR = 1.38; 95% CI, 0.81-2.35; OR = 2.34; 95% CI, 1.05-5.21; P(trend) = 0.02). A significant association was found among TCE-exposed subjects with at least one intact GSTT1 allele (active genotype; OR = 1.88; 95% CI, 1.06-3.33) but not among subjects with two deleted alleles (null genotype; OR = 0.93; 95% CI, 0.35-2.44; P(interaction) = 0.18). Similar associations for all exposure metrics including average intensity were observed among GSTT1-active subjects (OR = 1.56; 95% CI, 0.79-3.10; OR = 2.77; 95% CI, 1.01-7.58; P(trend) = 0.02) but not among GSTT1 nulls (OR = 0.81; 95% CI, 0.24-2.72; OR = 1.16; 95% CI, 0.27-5.04; P(trend) = 1.00; P(interaction) = 0.34). Further evidence of heterogeneity was seen among TCE-exposed subjects with >or=1 minor allele of several CCBL1-tagging single nucleotide polymorphisms: rs2293968, rs2280841, rs2259043, and rs941960. These findings provide the strongest evidence to date that TCE exposure is associated with increased renal cancer risk, particularly among individuals carrying polymorphisms in genes that are important in the reductive metabolism of this chemical, and provides biological plausibility of the association in humans.
Background: Base excision repair (BER) is a highly conserved essential mechanism for maintaining genome integrity. We examined associations among four well-characterized polymorphisms of BER genes ...(OGG1 Ser326Cys, XRCC1 Arg194Trp, XRCC1 Arg280His, and XRCC1 Arg399Gln) and lung cancer risk. Methods: A total of 2188 patients with lung cancer and 2198 control subjects without lung cancer recruited at 15 centers in six Eastern European countries from February 1998 to October 2002 provided DNA samples for genotype analysis. Genetic polymorphisms were analyzed by the fluorescence 5′ exonuclease and Amplifluor assays. Unconditional multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). We estimated the false-positive reporting probability (FPRP) for our results by incorporating a range of prior probabilities that specific polymorphisms are associated with lung cancer risk. All statistical tests were two-sided. Results: The overall odds ratio for lung cancer among those with the OGG1 Cys/Cys genotype compared with those with the OGG1 Ser/Ser genotype was 1.34 (95% CI = 0.95 to 1.88); the association was most prominent for adenocarcinoma risk (OR = 1.66, 95% CI = 1.04 to 2.66). Overall, the XRCC1 polymorphisms were not associated with the risk of lung cancer. However, the XRCC1 Arg194Trp and Arg280His variants were each associated with a reduced risk of lung cancer among subjects in the highest quartile of pack-years of smoking compared with common allele homozygotes (ORs of 0.65 95% CI = 0.46 to 0.93 and 0.56 95% CI = 0.36 to 0.86, respectively). The associations between the OGG1 Cys/Cys genotype and adenocarcinoma risk and between XRCC1 Arg194Trp polymorphism and lung cancer risk among heavy smokers remained robust given prior probabilities of 25% (FPRP = 0.238) and 10% (FPRP = 0.276), respectively. Conclusions: Our results do not support a major independent role of BER gene polymorphisms in lung cancer risk. However, we cannot exclude the possibility that the OGG1 Ser326Cys and XRCC1 Arg194Trp polymorphisms play minor roles in lung carcinogenesis.
This publication analyses current literary knowledge on selected topics in the fields of oral health and pathology, with a particular emphasis on the potential roles of the oral microbiome and ...preventative approaches to oral afflictions. An important association with floral dysbiosis has been documented in important oral conditions, sometimes as a predisposing factor and at other times as a result thereof. However, much remains to be elucidated regarding the specific mechanisms at play, as well as their meaning in clinical practice. Continued research into the pathophysiology of certain oral diseases is of particular importance considering how widespread they are. A specific emphasis should be placed on understanding the exact mechanisms through which the microbiota facilitates health, and when disturbed, sickness. And perhaps of most importance is the implementation of knowledge already acquired on disease prevention if the burden of oral diseases worldwide is to decline in the future.
Background: Incidence and mortality rates of upper aerodigestive tract cancers in Central Europe are among the highest in
the world and have increased substantially in recent years. This increase is ...likely to be due to patterns of alcohol and tobacco
consumption. Genetic susceptibility to upper aerodigestive tract cancer in relation to such exposures is an important aspect
that should be investigated among populations in this region.
Methods: A multicenter case-control study comprising 811 upper aerodigestive tract cancer cases and 1,083 controls was conducted
in: Bucharest (Romania), Lodz (Poland), Moscow (Russia), Banska Bystrika (Slovakia), and Olomouc and Prague (Czech Republic).
We analyzed six SNPs in three genes related to ethanol metabolism: alcohol dehydrogenase 1B and 1C ( ADH1B, ADH1C ) and aldehyde dehydrogenase 2 ( ALDH2 ).
Results: The ADH1B histidine allele at codon 48 was associated with a decreased risk of upper aerodigestive tract cancer; odds ratios (OR) were
0.36 95% confidence interval (95% CI), 0.17-0.77 for medium/heavy drinkers and 0.57 (95% CI, 0.36-0.91) for never/light
drinkers. Moderately increased risks were observed for the ADH1C 350 Val allele (OR, 1.19; 95% CI, 0.98-1.55) and ADH1C 272 Gln allele (OR, 1.24; 95% CI, 0.98-1.55). Medium/heavy drinkers who were heterozygous or homozygous at ALDH2 nucleotide position 248 were at a significantly increased risk of upper aerodigestive tract cancer (OR, 1.76; 95% CI, 1.13-2.75;
OR, 5.79; 95% CI, 1.49-22.5, respectively), with a significant dose response for carrying variant alleles ( P = 0.0007). Similar results were observed for the ALDH2 +82A>G and ALDH2 −261C>T polymorphisms. When results were analyzed by subsite, strong main effects were observed for squamous cell carcinoma
of the esophagus for all six variants. Among the 30% of the population who were carriers of at least one ALDH2 variant, the attributable fraction among carriers (AF c ) was 24.2% (5.7-38.3%) for all upper aerodigestive tract cancers, increasing to 58.7% (41.2-71.0%) for esophageal cancer.
Among carriers who drank alcohol at least thrice to four times a week, the AF c for having at least one ALDH2 variant was 49% (21.3-66.8%) for all upper aerodigestive tract cancers, increasing to 68.9% (42.9-83.1%) for esophageal cancer.
Conclusions: Polymorphisms in the ADH1B and ALDH2 genes are associated with upper aerodigestive tract cancer in Central European populations and interact substantially with
alcohol consumption. (Cancer Epidemiol Biomarkers Prev 2006;15(4):696–703)
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