Environment and cancer: who are susceptible?

Effects of water-saving irrigation on the residues and risk of polycyclic aromatic hydrocarbon in paddy field

The effects of different water-saving modes on PAHs residue and risk, field environment conditions and enzyme activities in paddy field were investigated in a field experiment plot in Laoyaba, Nanjing, China. Results showed that (1) water-saving treatment affected greatly the ΣPAHs in water and soil. The order of ΣPAHs residue in surface water and groundwater in farmland is as follows: dry fields<water-saving paddy field<flooding irrigation paddy field. The ΣPAHs in water during rice tillering stage were obviously higher than that in rice booting stage and milky stage, and the percentage of high-ring PAHs gradually reduced in water. (2) The residue of ΣPAHs in soil in flooding irrigation paddy field (534.4±186.7ng/g) were more than water-saving irrigation (454.3±128.1ng/g) and dry cultivation paddy field (430.2±143.4ng/g), and the ΣPAHs in dry field gradually decreased with the increase of water furrow number in farm. (3) When compared with flooding irrigation (337.87ng/g), water-saving (228.39ng/g) and dry cultivation (206.62ng/g) could obviously decrease the residue of ΣPAHs in rice tissues (35%-55%), generally the concentration of ΣPAHs in leaf>root>stem>rice grain. (4) Water-saving irrigation evidently decreased soil ecological risk (up to 55%-73%) and rice carcinogenic risk (up to 30%-45%) caused by PAHs compared with flooding irrigation. Water-saving irrigation could also reduce the Total Toxic Equivalency Concentration of PAHs in rice grain up to 50% relative to flooding irrigation. (5) The significant negative correlations were observed between the residual PAHs and the activities of laccase and dioxygenase (p<0.019), and the physical and chemical indexes (temperature, redox potential and dissolved oxygen of field, p<0.041). The changes of field environment conditions and enzyme activities induced by moisture control may be the main key factors affecting PAHs residue in water, soil and rice.

Temperature effect on phase state and reactivity controls atmospheric multiphase chemistry and transport of PAHs

Polycyclic aromatic hydrocarbons like benzo(a)pyrene (BaP) in atmospheric particulate matter pose a threat to human health because of their high carcinogenicity. In the atmosphere, BaP is mainly degraded through a multiphase reaction with ozone, but the fate and atmospheric transport of BaP are poorly characterized. Earlier modeling studies used reaction rate coefficients determined in laboratory experiments at room temperature, which may overestimate/underestimate degradation rates when applied under atmospheric conditions. Moreover, the effects of diffusion on the particle bulk are not well constrained, leading to large discrepancies between model results and observations. We show how regional and global distributions and transport of BaP can be explained by a new kinetic scheme that provides a realistic description of the temperature and humidity dependence of phase state, diffusivity, and reactivity of BaP-containing particles. Low temperature and humidity can substantially increase the lifetime of BaP and enhance its atmospheric dispersion through both the planetary boundary layer and the free troposphere. The new scheme greatly improves the performance of multiscale models, leading to better agreement with observed BaP concentrations in both source regions and remote regions (Arctic), which cannot be achieved by less-elaborate degradation schemes (deviations by multiple orders of magnitude). Our results highlight the importance of considering temperature and humidity effects on both the phase state of aerosol particles and the chemical reactivity of particulate air pollutants.

Ethical Dilemmas in Protecting Susceptible Subpopulations From Environmental Health Risks: Liberty, Utility, Fairness, and Accountability for Reasonableness

Various U.S. laws, such as the Clean Air Act and the Food Quality Protection Act, require additional protections for susceptible subpopulations who face greater environmental health risks. The main ethical rationale for providing these protections is to ensure that environmental health risks are distributed fairly. In this article, we (1) consider how several influential theories of justice deal with issues related to the distribution of environmental health risks; (2) show that these theories often fail to provide specific guidance concerning policy choices; and (3) argue that an approach to public decision making known as accountability for reasonableness can complement theories of justice in establishing acceptable environmental health risks for the general population and susceptible subpopulations. Since accountability for reasonableness focuses on the fairness of the decision-making process, not the outcome, it does not guarantee that susceptible subpopulations will receive a maximum level of protection, regardless of costs or other morally relevant considerations.

Chronic exposure to traffic-related air pollution and cancer incidence among 10,000 patients undergoing percutaneous coronary interventions: A historical prospective study

Background Exposure to traffic-related air pollution (TRAP) is considered to have a carcinogenic effect. The authors previously reported a nonsignificant association between TRAP and cancer risk in a relatively small cohort of myocardial infarction survivors. This study assessed whether TRAP exposure is associated with subsequent cancer in a large cohort of coronary patients. Methods & results Consecutive patients undergoing percutaneous coronary interventions in a major medical centre in central Israel from 2004 to 2014 were followed for cancer through 2015. Residential levels of nitrogen oxides (NO_x) - a proxy for TRAP - were estimated based on a high-resolution national land use regression model. Cox proportional hazards models were constructed to study relationships with cancer. Among 12,784 candidate patients, 9816 had available exposure data and no history of cancer (mean age, 68 years; 77% men). During a median (25th-75th percentiles) follow-up of 7.0 (3.9-9.3) years, 773 incident cases of cancer (8%) were diagnosed. In a multivariable-adjusted model, a 10-ppb increase in mean NO_x exposure was associated with hazard ratios (HRs) of 1.07 (95% confidence interval [CI] 1.00-1.15) for all-site cancer and 1.16 (95% CI 1.05-1.28) for cancers previously linked to TRAP (lung, breast, prostate, kidney and bladder). A stronger association was observed for breast cancer (HR = 1.43; 95% CI 1.12-1.83). Associations were slightly strengthened after limiting the cohort to patients with more precise exposure assessment. Conclusion Coronary patients exposed to TRAP are at increased risk of several types of cancer, particularly lung, prostate and breast. As these cancers are amenable to prevention strategies, identifying highly exposed patients may provide an opportunity to improve clinical care.

Metal Complexes as Self-Indicating Titrants for Acid-Base Reactions in Chloroform

The paper reports an unprecedented spectrophotometric determination of amines in chloroform, in which amines are not transformed into colored derivatives. This result has been achieved by exploiting the acid-base properties of the tight-ion-paired metal complexes [(HR₂DTO)Pt(H₂R₂DTO)][Cl], which are able to donate a HCl molecule to an amine, giving rise to an ammonium salt and to the neutral complexes [(HR₂DTO)₂Pt]. The circumstance that [(HR₂DTO)Pt(H₂R₂DTO)][Cl] and [(HR₂DTO)₂Pt] species show different absorptions in the visible region of the electromagnetic spectrum enables the aforementioned platinum complexes to behave as self-indicating titrants in the spectrophotometric determination of aliphatic amines, which are known to be UV-vis transparent. The new method has been tested by determining a series of fatty amines in the bulk and gave excellent results. The limits of applicability of this method (pK_a > 4) were found by testing a series of benzodiazepines.

In the Wrong Place with the Wrong SNP: The Association Between Stressful Neighborhoods and Cardiac Arrest Within Beta-2-adrenergic Receptor Variants

BACKGROUND

Sudden cardiac arrest has been linked independently both to stressful neighborhood conditions and to polymorphisms in the ADRB2 gene. The ADRB2 gene mediates sympathetic activation in response to stress. Therefore, if neighborhood conditions cause cardiac arrest through the stress pathway, the ADRB2 variant may modify the association between neighborhood conditions, such as socioeconomic deprivation and incidence of cardiac arrest.

METHODS

The Cardiac Arrest Blood Study Repository is a population-based repository of specimens and other data from adult cardiac arrest patients residing in King County, Washington. Cases (n = 1,539) were 25- to 100-year-old individuals of European descent who experienced out-of-hospital cardiac arrest from 1988 to 2004. Interactions between neighborhood conditions and the ADRB2 genotype on cardiac arrest risk were assessed in a case-only study design. Gene-environment independence was assessed in blood samples obtained from King County residents initially contacted by random-digit dialing.

RESULTS

Fewer than 4% of study subjects resided in socioeconomically deprived neighborhoods. Nonetheless, the case-only analysis indicated the presence of supramultiplicative interaction of socioeconomic deprivation and the homozygous Gln27Glu variant (case-only odds ratio: 1.8 [95% confidence interval: 1.0, 2.9]). Interactions between population density and the homozygous Gln27Glu variant were weaker (case-only odds ratio: 1.2 [95% confidence interval: 0.97, 1.5]).

CONCLUSIONS

Findings support a supramultiplicative interaction between the Gln27Glu ADRB2 variant and socioeconomic deprivation among individuals of European descent. This result is consistent with the hypothesis that the elevation in cardiac arrest risk associated with socioeconomic deprivation operates through the stress pathway.

Polymorphisms in TIM-3 and breast cancer susceptibility in Chinese women: A case-control study

Previous studies have found associations between polymorphisms in T cell immunoglobulin and mucin domain 3 (TIM-3) and increased risks of various cancers. However, the association between TIM-3 polymorphisms and breast cancer (BC) remains uncertain. In this study, a total of 560 BC patients and 583 age, sex, and ethnicity-matched healthy controls from Northwest China were included. The polymorphisms were genotyped using Sequenom MassARRAY. The expression level of TIM-3 protein was detected by immunohistochemistry. We observed rs10053538 had a significantly increased risk of BC, comparing with the wild-type genotype even after Bonferroni correction. In addition, the rs4704853 G>A variants were more frequent among BC patients than the controls (GA + AA vs. GG: OR = 1.32, 95% CI = 1.03-1.69, P = 0.026); However, the significance was lost after Bonferroni correction (P = 0.078). Furthermore, rs10053538 was associated with lymph node metastasis. Age stratification revealed that among patients aged <49 years, those with the rs4704853 GA/AA genotype had a higher risk of BC; But there was no difference when Bonferroni correction was conducted. Immunohistochemical analysis showed that the expression of TIM-3 protein in the breast cancer tissues was higher in patients carrying the rs10053538 GT+TT genotype than those with GG genotype (P = 0.012). However, we failed to find any difference between BC patients and controls in any rs1036199 genetic model. These findings suggested that rs10053538 in TIM-3 might increase susceptibility to BC and promote the progression of BC in Chinese women.

Formation of bicyclic polycyclic aromatic hydrocarbons (PAHs) from the reaction of a phenyl radical with cis-3-penten-1-yne

The formation of PAHs within 4-, 5-, 6- and 7-membered rings on the C₆H₅ + C₅H₆ potential energy surface.

FLT3-ITD, NPM1, and DNMT3A Gene Mutations and Risk Factors in Normal Karyotype Acute Myeloid Leukemia and Myelodysplastic Syndrome Patients in Upper Northern Thailand

Objective:

Approximately 40-45% of AML and MDS patients have a cytogenetically normal karyotype (CN-AML and CN-MDS). The frequency and types of gene mutations in these cases may differ among various populations. The objective of this study was to identify frequencies and types of FLT3-ITD, NPM1, and DNMT3A mutations, and associations of them with clinical data and risk factors in CN-AML and CN-MDS cases in upper Northern Thailand.

Methods:

Bone marrow samples of 40 CN-AML and 60 CN-MDS patients were analyzed for gene mutations by direct sequencing. In addition, data for potential risk factors were obtained for comparison.

Results:

Frequencies of FLT3-ITD, NPM1, and DNMT3A mutations were 25.0%, 17.5%, and 10.0%, respectively in CN-AML, but all zero in CN-MDS cases. NPM1 mutations were found at a median age older than the wild type (58 vs 47 years) while DNMT3A mutations were associated with an increase in the white blood cell count. In all patients, factors for the mutations of these three genes included age ≤ 60 years, and a history of hypertension.

Conclusion:

When considering mutations in only normal karyotype patients, the frequency of FLT3-ITD, NPM1, DNMT3A mutations in CN-AML patients in upper Northern Thailand were found to occur at lower rates than in Western patients and to differ from other Asian populations including parts of Thailand. No mutations were observed in CN-MDS cases. Some types of gene mutations differed from previous studies, possibly attributable to differences in geography, lifestyle and genetic backgrounds. Links with age ≤ 60 years and history of hypertension were found. Investigation of these three genes in an intermediate risk group with a normal karyotype is useful for a better understanding of molecular leukemogenetic steps in CN-AML and CN-MDS patients and may be beneficial for planning treatment and prevention in the population of upper Northern Thailand.

Composite of PAH-degrading endophytic bacteria reduces contamination and health risks caused by PAHs in vegetables

Vegetables accumulate polycyclic aromatic hydrocarbons (PAHs) at high concentrations when grown in contaminated sites. Inoculation with PAH-degrading endophytic bacteria (EB_PAH) has been recognized as one of the most promising ways to remove PAHs from plant bodies; however, the performance of single endophytic bacteria is generally limited. This investigation used a composite of eight EB_PAH to reduce the contamination and health risk posed by 16 EPA priority PAHs in vegetables including Chinese cabbage (Brassica chinensis L.) and pakchoi (Brassica campestris L.). Composite EB_PAH have strong PAH degradation abilities, and more than 65% of ∑PAH were degraded after 10-day insuspension with composite EB_PAH. Vegetable were contacted with composite EB_PAH by seed soaking (SS) and leaf painting (LP) with an EB_PAH cell incubation at OD_600nm=0.2-1.5. Compared with those in non-inoculated controls, the ∑PAH concentrations in edible parts of Chinese cabbage and pakchoi colonized by composite EB_PAH via SS and LP with bacterial suspension at OD_600nm=0.2-1.5 were 42.07-70.77% and 15.79-53.20% lower, and the incremental lifetime cancer risk (ILCR) values for males and females were 31.78-84.08% and 26.60-83.40% smaller, respectively. SS was the optimal inoculation method for reducing PAH concentrations and ILCR values. Our results indicate that inoculating plants with composite EB_PAH can lower the health risk posed by vegetables contaminated with PAHs, and may be used to mitigate plant PAH contamination.

Fate of phenanthrene and mineralization of its non-extractable residues in an oxic soil

The fate of organic pollutants in the environment, especially the formation and stability of non-extractable (i.e., bound) residues (NERs) determines their environmental risk. Using ¹⁴C-tracers, we studied the fate of the carcinogen phenanthrene in active or sterilized oxic loamy soil in the absence and presence of the geophagous earthworm Metaphire guillelmi and characterized the NERs derived from phenanthrene. After incubation of ¹⁴C-phenanthrene in active soil for 28 days, 40 ± 3.1% of the initial amount was mineralized and 70.1 ± 1.9% was converted to NERs. Most of the NERs (>92%) were bound to soil humin. Silylation of the humin-bound residues released 45.3 ± 5.3% of these residues, which indicated that they were physically entrapped, whereas the remainder of the residues were chemically bound or biogenic. By contrast, in sterilized soil, only 43.4 ± 12.6% of the phenanthrene was converted to NERs and all of these residues were completely released upon silylation, which underlines the essential role of microbial activity in NER formation. The presence of M. guillelmi in active soil significantly inhibited phenanthrene mineralization (24.4 ± 2.6% mineralized), but NER formation was not significantly affected. Only a small amount of phenanthrene-derived residues (1.9-5.3% of the initial amount) accumulated in the earthworm body. When humin-bound residues were mixed with fresh soil, 33.9% (humin recovered from active soils) and 12.4% (humin recovered from sterilized soils) of the residues were mineralized after 75 days of incubation, respectively, which indicated a high bioavailability of NERs, albeit lower than the initial addition of phenanthrene. Our results indicated that many phenanthrene-derived NERs, especially those physically entrapped, are still bioavailable and may pose a toxic threat to soil organisms.

Asbestos ingestion and gastrointestinal cancer: a possible underestimated hazard

The presence of asbestos fibres (AFs) in drinking water could be linked with gastrointestinal cancers. However, it is not regulated in several countries due to conflicting evidence. Areas covered: Some reports mainly associated AF ingestion with gastric and colorectal cancer. Experimental evidence suggested a role for timing and extent of exposure, and showed that ingested AFs induce toxic effects on the stomach, ileum and colon, histological alterations and negative effects at a molecular level, cross the placenta and enter foetal organs (including the liver), and seem able to act as a co-carcinogen agent. Occupational studies suggest associations between asbestos exposure and intrahepatic cholangiocarcinoma, and observations exist indicating the possibility that AFs could enter the liver and bile through enteric absorption. Expert commentary: A risk threshold (AF concentration in drinking water) for digestive cancers has not been convincingly identified so far and regulations, where adopted, have weak scientific basis and may not be adequate. With further and more definitive studies, evidence might become sufficient to justify monitoring plans, persuade countries with no current limits to set a maximum level of AFs in drinking water and might induce a revision of the existing legislations, pointing to efficient primary prevention policies.

Associations of NQO1 C609T and NQO1 C465T polymorphisms with acute leukemia risk: a PRISMA-compliant meta-analysis

Objective

The NAD(P)H:quinone oxidoreductase (NQO1) C609T and C465T polymorphisms have been widely thought to be associated with the risk of acute leukemia (AL) in recent years, but the correlations are still unclear. A meta-analysis is generally acknowledged as one of the best methods for secondary research, and so it was applied in this study with the aim of elucidating how the NQO1 C609T and C465T polymorphisms are related to the risk of AL.

Methods

Relevant studies were searched in the PubMed, EMBASE, CNKI, and Wanfang databases, and the obtained data were analyzed using Stata (version 12.1). The allele-contrast model was applied, and odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate relationship strengths. Meta-regression was used to identify sources of heterogeneity, and subgroup analyses were conducted. Publication bias was analyzed using funnel plots, with the trim-and-fill method used to analyze the effect of publication bias on pooled results. In addition, sensitivity analysis, the fail-safe number method, and cumulative analysis by publication year were performed to measure the stability of the obtained results.

Results

This meta-analysis included 28 relevant studies involving 5,953 patients and 8,667 controls. Overall, the C609T polymorphism was associated with the risk of acute lymphoblastic leukemia (ALL; OR =1.18, 95% CI =1.00–1.39, P=0.05). Meanwhile, race was found to be a potential source of heterogeneity for the relationship between the C609T polymorphism and acute myeloid leukemia (AML) risk, and the subgroup analysis identified the C609T polymorphism as a risk factor for AML in Asians (OR =1.34, 95% CI =1.03–1.74, P=0.03). The number of studies about C465T polymorphism was too small to pool the data.

Conclusion

There are increased risks of ALL in all subjects and of AML in Asians for carriers of the NQO1 C609T polymorphism. Further studies are needed to verify the associations of the C465T polymorphism with the risk of AL.

Biomarkers of the health outcomes associated with ambient particulate matter exposure

Epidemiologic evidence supports the positive association of cardiopulmonary morbidity and mortality, and lung cancer risk with exposure to airborne particulate matter (PM). Oxidative stress and inflammation have been proposed to be the major causal factors involved in mediating PM effects on both cardiovascular and pulmonary health outcomes. However, the mechanism whereby PM causes the health effects is not fully elucidated. To evaluate and investigate human exposure to PM, it is essential to have a specific, sensitive and robust characterization of individual exposure to PM. Biomarkers may mark important intermediate steps leading to overt health effects after PM exposure. Thus biomarkers are promising indicators, which could serve as representative measures of the exposure to PM for assessing the health impacts and understanding the mechanism. Indeed, a number of biomarkers are already in use in the field of epidemiological studies and toxicological research. However, we are facing now the challenges to select robust, specific and sensitive biomarkers, which can be employed in large-scale of population to assess the health risk and to monitor the effectiveness of interventions. In this review, we describe a range of biomarkers that are associated with air pollution exposure, particularly markers of oxidative stress, inflammatory factors, and microRNAs, as well as markers of pollutants metabolites. Understanding the nature of the association of these biomarkers with PM exposure may shed some light on the process of selecting biomarkers for large-scale population studies, developing novel preventative and therapeutic strategies.

Risk assessment of polycyclic aromatic hydrocarbons (PAHs) in River Nile up- and downstream of a densely populated area

A biomonitoring study was conducted to evaluate levels of eleven polycyclic aromatic hydrocarbons (PAHs) in water, sediment and wild Nile tilapia (Oreochromis niloticus) samples collected up- and downstream of Cairo sector of the River Nile, Egypt. The scaled mass index (SMI), as a fish body mass-length relationship, performed better in indicating the ecosystem and fish conditions. The total PAHs in water samples had a range of 0.0156-0.0269 mg/L, while that in sediment samples ranged from 0.723 to 1.078 mg/kg dry weight and that in fish muscles ranged from 4.065 to 10.033 mg/kg wet weight. Pollutant source appraisal was determined by diagnostic ratios and proved the predominance of pyrogenic sources in water, petrogenic sources in fish, and mixed source origin in sediment. Human health risks associated with fish consumption showed that non-cancer adverse health effects are not expected to occur but the calculated lifetime cancer risk (LCR) for the total PAHs proved that the fish muscles are not safe for human consumption at both sites. Regular monitoring programs and mitigation efforts should be considered in the near future along such areas heavily influenced by human activities.

Global long-range transport and lung cancer risk from polycyclic aromatic hydrocarbons shielded by coatings of organic aerosol

Polycyclic aromatic hydrocarbons (PAHs) have toxic impacts on humans and ecosystems. One of the most carcinogenic PAHs, benzo(a)pyrene (BaP), is efficiently bound to and transported with atmospheric particles. Laboratory measurements show that particle-bound BaP degrades in a few hours by heterogeneous reaction with ozone, yet field observations indicate BaP persists much longer in the atmosphere, and some previous chemical transport modeling studies have ignored heterogeneous oxidation of BaP to bring model predictions into better agreement with field observations. We attribute this unexplained discrepancy to the shielding of BaP from oxidation by coatings of viscous organic aerosol (OA). Accounting for this OA viscosity-dependent shielding, which varies with temperature and humidity, in a global climate/chemistry model brings model predictions into much better agreement with BaP measurements, and demonstrates stronger long-range transport, greater deposition fluxes, and substantially elevated lung cancer risk from PAHs. Model results indicate that the OA coating is more effective in shielding BaP in the middle/high latitudes compared with the tropics because of differences in OA properties (semisolid when cool/dry vs. liquid-like when warm/humid). Faster chemical degradation of BaP in the tropics leads to higher concentrations of BaP oxidation products over the tropics compared with higher latitudes. This study has profound implications demonstrating that OA strongly modulates the atmospheric persistence of PAHs and their cancer risks.

Observation of covalent and electrostatic bonds in nitrogen-containing polycyclic ions formed by gas phase reactions of the benzene radical cation with pyrimidine

This work reports a new formation mechanism for the nitrogen-containing polycyclic ions in the gas phase.

Effects of nanoplastics and microplastics on toxicity, bioaccumulation, and environmental fate of phenanthrene in fresh water

Contamination of fine plastic particles (FPs), including micrometer to millimeter plastics (MPs) and nanometer plastics (NPs), in the environment has caught great concerns. FPs are strong adsorbents for hydrophobic toxic pollutants and may affect their fate and toxicity in the environment; however, such information is still rare. We studied joint toxicity of FPs with phenanthrene to Daphnia magna and effects of FPs on the environmental fate and bioaccumulation of ¹⁴C-phenanthrene in fresh water. Within the five sizes particles we tested (from 50 nm to 10 μm), 50-nm NPs showed significant toxicity and physical damage to D. magna. The joint toxicity of 50-nm NPs and phenanthrene to D. magna showed an additive effect. During a 14-days incubation, the presence of NPs significantly enhanced bioaccumulation of phenanthrene-derived residues in daphnid body and inhibited the dissipation and transformation of phenanthrene in the medium, while 10-μm MPs did not show significant effects on the bioaccumulation, dissipation, and transformation of phenanthrene. The differences may be attributed to higher adsorption of phenanthrene on 50-nm NPs than 10-μm MPs. Our findings underlined the high potential ecological risks of FPs, and suggested that NPs should be given more concerns, in terms of their interaction with hydrophobic pollutants in the environment.

Advances in Understanding How Heavy Metal Pollution Triggers Gastric Cancer

With the development of industrialization and urbanization, heavy metals contamination has become a major environmental problem. Numerous investigations have revealed an association between heavy metal exposure and the incidence and mortality of gastric cancer. The mechanisms of heavy metals (lead, cadmium, mercury, chromium, and arsenic) contamination leading to gastric cancer are concluded in this review. There are four main potential mechanisms: (1) Heavy metals disrupt the gastric mucosal barrier by decreasing mucosal thickness, mucus content, and basal acid output, thereby affecting the function of E-cadherin and inducing reactive oxygen species (ROS) damage. (2) Heavy metals directly or indirectly induce ROS generation and cause gastric mucosal and DNA lesions, which subsequently alter gene regulation, signal transduction, and cell growth, ultimately leading to carcinogenesis. Exposure to heavy metals also enhances gastric cancer cell invasion and metastasis. (3) Heavy metals inhibit DNA damage repair or cause inefficient lesion repair. (4) Heavy metals may induce other gene abnormalities. In addition, heavy metals can induce the expression of proinflammatory chemokine interleukin-8 (IL-8) and microRNAs, which promotes tumorigenesis. The present review is an effort to underline the human health problem caused by heavy metal with recent development in order to garner a broader perspective.

Spatial and Seasonal Variations of Polycyclic Aromatic Hydrocarbons (PAHs) in Ambient Particulate Matter (PM10, PM2.5) in Three Mega-Cities in China and Identification of Major Contributing Source Types

Beijing, is the political, economic and cultural center of China. Tianjin and Shijiazhuang, located close to Beijing are also two mega-cities with huge population. The rapid economic development in the three cities in the last decades has caused severe air pollution problems, especially airborne PAHs pollution, in both gaseous and particulate phases, which has resulted in considerable harm to the health of local residents. In this study, a total of 671 air samples were collected in the three cities and reference site, and four national air quality background sites. Concentrations and seasonal variations were discussed to describe the pollution status and identify possible sources. The results showed that concentrations of BaP, a PAH that serves as an indicator of PAH pollution, exceeded the Chinese national standard by 4-12 times. PAH concentrations varied significantly in different seasons, with similar trends in the three cities. The toxic equivalents quantity (i.e., quantity of total PAHs with an equivalent toxicity to BaP) ranged from 13.35 to 22.54 ng/m(3) during the central heating period of winter and spring. These concentrations greatly exceeded the Chinese national standards for 24-h average (2.5 ng/m(3)) and annual average (1.0 ng/m(3)) concentrations of BaP. Two ratios that are indicative of PAH source, Pyr/BaP and BaP/BghiP, revealed that high percentages of the PAH pollution were contributed by coal combustion.

Review: the Contribution of both Nature and Nurture to Carcinogenesis and Progression in Solid Tumours

Cancer is a leading cause of mortality worldwide. Cancer arises due to a series of somatic mutations that accumulate within the nucleus of a cell which enable the cell to proliferate in an unregulated manner. These mutations arise as a result of both endogenous and exogenous factors. Genes that are commonly mutated in cancer cells are involved in cell cycle regulation, growth and proliferation. It is known that both nature and nurture play important roles in cancer development through complex gene-environment interactions; however, the exact mechanism of these interactions in carcinogenesis is presently unclear. Key environmental factors that play a role in carcinogenesis include smoking, UV light and oncoviruses. Angiogenesis, inflammation and altered cell metabolism are important factors in carcinogenesis and are influenced by both genetic and environmental factors. Although the exact mechanism of nature-nurture interactions in solid tumour formation are not yet fully understood, it is evident that neither nature nor nurture can be considered in isolation. By understanding more about gene-environment interactions, it is possible that cancer mortality could be reduced.

Interaction between APC and Fen1 during breast carcinogenesis

Aberrant DNA base excision repair (BER) contributes to malignant transformation. However, inter-individual variations in DNA repair capacity plays a key role in modifying breast cancer risk. We review here emerging evidence that two proteins involved in BER - adenomatous polyposis coli (APC) and flap endonuclease 1 (Fen1) - promote the development of breast cancer through novel mechanisms. APC and Fen1 expression and interaction is increased in breast tumors versus normal cells, APC interacts with and blocks Fen1 activity in Pol-β-directed LP-BER, and abrogation of LP-BER is linked with cigarette smoke condensate-induced transformation of normal breast epithelial cells. Carcinogens increase expression of APC and Fen1 in spontaneously immortalized human breast epithelial cells, human colon cancer cells, and mouse embryonic fibroblasts. Since APC and Fen1 are tumor suppressors, an increase in their levels could protect against carcinogenesis; however, this does not seem to be the case. Elevated Fen1 levels in breast and lung cancer cells may reflect the enhanced proliferation of cancer cells or increased DNA damage in cancer cells compared to normal cells. Inactivation of the tumor suppressor functions of APC and Fen1 is due to their interaction, which may act as a susceptibility factor for breast cancer. The increased interaction of APC and Fen1 may occur due to polypmorphic and/or mutational variation in these genes. Screening of APC and Fen1 polymorphic and/or mutational variations and APC/Fen1 interaction may permit assessment of individual DNA repair capability and the risk for breast cancer development. Such individuals might lower their breast cancer risk by reducing exposure to carcinogens. Stratifying individuals according to susceptibility would greatly assist epidemiologic studies of the impact of suspected environmental carcinogens. Additionally, a mechanistic understanding of the interaction of APC and Fen1 may provide the basis for developing new and effective targeted chemopreventive and chemotherapeutic agents.

Secondary Adult Acute Myeloid Leukemia: a Review of Our Evolving Understanding of a Complex Disease Process

OPINION STATEMENT

Secondary AML (s-AML) encompasses AML evolving from myelodysplasia (AML-MDS) and treatment-related AML (t-AML) after exposure to chemotherapy, radiation, or environmental toxins. S-AML has traditionally been considered a devastating disease, affecting a vulnerable population of heavily pretreated, older adults. A limited understanding of disease pathogenesis/heterogeneity and lack of effective treatments have hampered overall improvements in patient outcomes. With the recent understanding that the secondary nature of sAML does not by itself incur a poor prognosis and incorporation of cytogenetics and molecular genetics into patient care and the advancement of treatment, including improved supportive care, novel chemotherapeutics agents, and nonmyeloablative conditioning regimens as part of allogeneic hematopoietic cell transplantation (HCT), modest gains in survival and quality of life are beginning to be seen among patients with s-AML.

Exposure of school children to polycyclic aromatic hydrocarbons, heavy metals and radionuclides in the urban soil of Kragujevac city, Central Serbia

The concentrations of radionuclides, polycyclic aromatic hydrocarbons (PAHs) and heavy metals were measured in soil samples collected from school backyards and playgrounds in Kragujevac, one of the largest cities of Central Serbia. The activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined using the HPGe semiconductor detector. The average values were 34.6, 44.7, 428.9 and 45.1 Bq kg(-1), respectively. The correlation between the activity concentrations of (226)Ra in the soil samples and the results of the previous measurement of (222)Rn concentrations in the indoor air was examined. The absorbed dose rates, the annual effective doses and excess lifetime cancer risk were also estimated. The activity concentrations of (226)Ra and (232)Th have shown normal distribution. The collected soil samples were analysed for PAHs by HPLC. All analysed soil samples contained PAHs, and their total amounts (for 15 measured compounds) were found to be between 0.038 and 3.136 mg kg(-1) of absolutely dry soil (a.d.s). In addition the concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in the fourteen soil samples collected from the playgrounds of kindergartens.

Molecular epidemiology of acute leukemia in children: causal model, interaction of three factors-susceptibility, environmental exposure and vulnerability period

Acute leukemias have a huge morphological, cytogenetic and molecular heterogeneity and genetic polymorphisms associated with susceptibility. Every leukemia presents causal factors associated with the development of the disease. Particularly, when three factors are present, they result in the development of acute leukemia. These phenomena are susceptibility, environmental exposure and a period that, for this model, has been called the period of vulnerability. This framework shows how the concepts of molecular epidemiology have established a reference from which it is more feasible to identify the environmental factors associated with the development of leukemia in children. Subsequently, the arguments show that only susceptible children are likely to develop leukemia once exposed to an environmental factor. For additional exposure, if the child is not susceptible to leukemia, the disease does not develop. In addition, this exposure should occur during a time window when hematopoietic cells and their environment are more vulnerable to such interaction, causing the development of leukemia. This model seeks to predict the time when the leukemia develops and attempts to give a context in which the causality of childhood leukemia should be studied. This information can influence and reduce the risk of a child developing leukemia.

To quit or not: Vulnerability of women to smoking tobacco

Tobacco smoking is currently on the rise among women, and can pose a greater health risk. In order to understand the nature of the increase in smoking prevalence among women, we focused on the vulnerability of women to smoking behaviors--smoking cessation or tobacco addiction--and performed a systematic review of the socioeconomic and intrinsic factors as well as tobacco ingredients that affect women's susceptibility to smoking tobacco. We observed that nicotine and other tobacco components including cocoa-relatives, licorice products, and menthol aggravate tobacco addiction in women rather than in men. Various genetic and epigenetic alterations in dopamine pathway and the pharmaco-kinetics and -dynamic factors of nicotine also showed potential evidences for high susceptibility to tobacco addiction in women. Therefore, we suggest systemic approaches to prevent tobacco smoking-related health risks, considering gene-environment-gender interaction.

Association Between X-Ray Cross-complementing Group 3 (XRCC3) Thr241Met Polymorphism and Risk of Thyroid Cancer: A Meta-Analysis

Background

The X-ray cross-complementing group 3 (XRCC3) gene encodes a protein that plays an important role in homologous recombination repair (HRR) of DNA double-strand break (DSB). Increasing attention has been drawn to the association of XRCC3 T241M polymorphism with various types of human cancers. In this study, a meta-analysis was performed to investigate whether there is an association between XRCC3 T241M polymorphism and thyroid cancer risk.

Material/Methods

A comprehensive search was conducted and a total of 8 studies that covered 963 thyroid cancer cases and 1942 controls were included in this analysis. The meta-analysis was performed on both overall database and 2 ethnic subgroups (Caucasian and Asian). The fixed-effects model was used to calculate odds ratio (OR) with 95% confidence intervals (CIs). The publication bias was evaluated using Begg’s funnel plots and Egger’s test.

Results

A positive association between XRCC3 T241M polymorphism and thyroid cancer risk was found by the analyses of the overall database using both recessive model (OR=1.40, 95% CI=1.08–1.81, P=0.012) and homozygote comparison (OR=1.41, 95% CI=1.07–1.86, P=0.015), but not by that using the dominant model (OR=1.12, 95% CI=0.95–1.33, P=0.18). However, no significant association of XRCC3 Thr241Met polymorphism with the risk of thyroid cancer was found in individual ethnic subgroups.

Conclusions

We conclude that the XRCC3 Thr241Met polymorphism is associated with an increased risk of thyroid cancer in the overall population, while no significant association was observed in individual ethnic subgroups due to limited population size.

Molecular mechanisms underlying anticancer effects of myricetin

Dietary guidelines published in the past two decades have acknowledged the beneficial effects of myricetin, an important and common type of herbal flavonoid, against several human diseases such as inflammation, cardiovascular pathologies, and cancer. An increasing number of studies have shown the beneficial effects of myricetin against different types of cancer by modifying several cancer hallmarks including aberrant cell proliferation, signaling pathways, apoptosis, angiogenesis, and tumor metastasis. Most importantly, myricetin interacts with oncoproteins such as protein kinase B (PKB) (Akt), Fyn, MEK1, and JAK1-STAT3 (Janus kinase-signal transducer and activator of transcription 3), and it attenuates the neoplastic transformation of cancer cells. In addition, myricetin exerts antimitotic effects by targeting the overexpression of cyclin-dependent kinase 1 (CDK1) in liver cancer. Moreover, it also targets the mitochondria and promotes different kinds of cell death in various cancer cells. In the present paper, a critical review of the available literature is presented to identify the molecular targets underlying the anticancer effects of myricetin.

Therapy-related acute myeloid leukemia in patients with lymphoma: A report of four cases and review of the literature

Due to advances in the treatment of lymphoma, the remission and overall survival rates for this disease have improved in recent years. However, the incidence of therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) has increased. In order to further the understanding of the mechanisms of t-MDS/AML and reduce its incidence, the present study reports 4 cases of t-AML following treatment for lymphoma. The 4 patients presented aggressive forms of lymphoma in stage III/IV, and 3 were diagnosed with non-Hodgkin's lymphoma. All patients had previously undergone chemotherapy containing alkylating agents and/or topoisomerase II inhibitors. The latency period between the time of primary diagnosis and occurrence of t-AML ranged from 15 to 42 months. At the time of diagnosis of t-AML, 3 of the 4 patients presented pancytopenia, whilst the remaining patient exhibited leukocytosis. The majority of the patients succumbed to their disease within 1 year of t-AML diagnosis, with the exception of the patient in case 3, who survived following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The present cases indicate that an advanced stage of disease at the time of primary diagnosis, prior exposure to radiotherapy, and administration of ≥4 regimens and ≥8 cycles of chemotherapy may be risk factors for the development of t-AML. Based on the present findings and a review of the literature, we propose that allo-HSCT should be recommended for patients at high risk of developing t-AML. In addition, chimeric antigen receptor T-cell immunotherapy may constitute a novel type of immunotherapy for the treatment of cancer, particularly for cases of relapsed and refractory lymphoma or leukemia.

Blood miRNAs as sensitive and specific biological indicators of environmental and occupational exposure to volatile organic compound (VOC)

To date, there is still shortage of highly sensitive and specific minimally invasive biomarkers for assessment of environmental toxicants exposure. Because of the significance of microRNA (miRNA) in various diseases, circulating miRNAs in blood may be unique biomarkers for minimally invasive prediction of toxicants exposure. We identified and validated characteristic miRNA expression profiles of human whole blood in workers exposed to volatile organic compounds (VOCs) and compared the usefulness of miRNA indicator of VOCs with the effectiveness of the already used urinary biomarkers of occupational exposure. Using a microarray based approach we screened and detected deregulated miRNAs in their expression in workers exposed to VOCs (toluene [TOL], xylene [XYL] and ethylbenzene [EBZ]). Total 169 workers from four dockyards were enrolled in current study, and 50 subjects of them were used for miRNA microarray analysis. We identified 467 miRNAs for TOL, 211 miRNAs for XYL, and 695 miRNAs for XYL as characteristic discernible exposure indicator, which could discerned each VOC from the control group with higher accuracy, sensitivity, and specificity than urinary biomarkers. Current observations from this study point out that the altered levels of circulating miRNAs can be a reliable novel, minimally invasive biological indicator of occupational exposure to VOCs.

Association between three eNOS polymorphisms and cancer risk: a meta-analysis

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene may influence the risk of cancer, but the results are still debatable. Therefore, we performed a systematic review to provide a more complete picture and conducted a meta-analysis to derive a precise estimation. We searched PubMed, EMBASE, EBSCO, Google Scholar and China National Knowledge Infrastructure (CNKI) databases until April 2014 to identify eligible studies. Thirty-one studies with cancer patients and controls were included in the meta-analysis. Overall, the polled analysis revealed that the T-786C polymorphism was significantly associated with increased cancer risk under multiple genetic models (C vs T: OR=1.135, 95%CI=1.048-1.228; CC vs TT: OR=1.278, 95%CI=1.045- 1.562; TC vs TT: OR=1.136, 95%CI=1.023-1.261; CC+TC vs TT: OR=1.159, 95%CI=1.047-1.281; CC vs TC+TT: OR=1.204, 95%CI= 1.003-1.447). G894T was associated with significant risk for females (TT vs GG: OR=1.414, 95%CI=1.056-1.892; TT vs GT+GG: OR=1.356, 95%CI=1.108-1.661) and for breast cancer (T vs G: OR=1.097, 95%CI=1.001-1.203; TT vs GG: OR=1.346, 95%CI=1.012-1.789; TT vs GT+GG: OR=1.269, 95%CI=1.028-1.566). Increased susceptibility was revealed for prostate cancer with 4a/b (ba vs bb: OR=1.338, 95%CI=1.013-1.768; aa+ba vs bb: OR=1.474, 95%CI=1.002-2.170). This meta-analysis indicated that the eNOS T-786C polymorphism is associated with elevated cancer risk; the G894T polymorphism contributes to susceptibility to breast cancer and cancer generally in females; and the 4a/b polymorphism may be associated with prostate cancer risk.

Association of MMP7 -181A→G Promoter Polymorphism with Gastric Cancer Risk: INFLUENCE OF NICOTINE IN DIFFERENTIAL ALLELE-SPECIFIC TRANSCRIPTION VIA INCREASED PHOSPHORYLATION OF cAMP-RESPONSE ELEMENT-BINDING PROTEIN (CREB)

Elevated expression of matrix metalloproteinase7 (MMP7) has been demonstrated to play a pivotal role in cancer invasion. The -181A→G (rs11568818) polymorphism in the MMP7 promoter modulates gene expression and possibly affects cancer progression. Here, we evaluated the impact of -181A→G polymorphism on MMP7 promoter activity and its association with gastric cancer risk in eastern Indian case-control cohorts (n = 520). The GG genotype as compared with the AA genotype was predisposed (p = 0.02; odds ratio = 1.9, 95% confidence interval = 1.1-3.3) to gastric cancer risk. Stratification analysis showed that tobacco addiction enhanced gastric cancer risk in GG subjects when compared with AA subjects (p = 0.03, odds ratio = 2.46, and 95% confidence interval = 1.07-5.68). Meta-analysis revealed that tobacco enhanced the risk for cancer more markedly in AG and GG carriers. Activity and expression of MMP7 were significantly higher in GG than in AA carriers. In support, MMP7 promoter-reporter assays showed greater transcriptional activity toward A to G transition under basal/nicotine-induced/cAMP-response element-binding protein (CREB) overexpressed conditions in gastric adenocarcinoma cells. Moreover, nicotine (a major component of tobacco) treatment significantly up-regulated MMP7 expression due to enhanced CREB phosphorylation followed by its nuclear translocation in gastric adenocarcinoma cells. Furthermore, chromatin immunoprecipitation experiments revealed higher binding of phosphorylated CREB with the -181G than the -181A allele. Altogether, specific binding of phosphorylated CREB to the G allele-carrying promoter enhances MMP7 gene expression that is further augmented by nicotine due to increased CREB phosphorylation and thereby increases the risk for gastric cancer.

Risk of cancer in patients with cholecystitis: a nationwide population-based study

OBJECTIVE

The objective of this study was to evaluate the risk of cancer in patients diagnosed with cholecystitis and possible interactions between cholecystitis and cholecystectomy.

METHODS

A retrospective population-based cohort study was conducted among patients diagnosed with cholecystitis that were registered in the National Health Insurance Research Database in Taiwan between January 1, 2000 and December 31, 2010. Standardized incidence ratios (SIRs) were calculated to compare the incidence of cancer in these patients to that of the general population. Adjusted hazard ratios (HRs) were also calculated to investigate whether cholecystitis increased the risk for specific cancers.

RESULTS

During a median observation period of 5.4 years, 1541 cancers occurred in 20,431 patients with cholecystitis, yielding a SIR of 1.97 (95% confidence interval [CI], 1.88-2.07). A significantly greater risk of biliary tract cancer (adjusted HR 1.72; 95% CI, 1.08-2.75) was observed after adjusting for potential risk factors. In contrast, cholecystectomy was found to attenuate the cancer risk, with the reduction of adjusted HR from 2.34 (95% CI, 1.62-3.37) to 1.28 (95% CI, 0.76-2.14).

CONCLUSION

Cholecystitis is an independent risk factor to extrahepatic biliary tract cancers, whereas cholecystectomy can attenuate the cancer risk of cholecystitis.

A crossed molecular beam and ab initio study on the formation of 5- and 6-methyl-1,4-dihydronaphthalene (C11H12) via the reaction of meta-tolyl (C7H7) with 1,3-butadiene (C4H6)

The crossed molecular beam reactions of the meta-tolyl radical with 1,3-butadiene and D6-1,3-butadiene were conducted at collision energies of 48.5 kJ mol⁻¹ and 51.7 kJ mol⁻¹.

Pharmacogenetics of SULT1A1

Cytosolic SULT1A1 participates in the bioconversion of a plethora of endogenous and xenobiotic substances. Genetic variation in this important enzyme such as SNPs can vary by ethnicity and have functional consequences on its activity. Most SULT1A1 genetic variability studies have been centered on the SULT1A1*1/2 SNP. Highlighted here are not only this SNP, but other genetic variants associated with SULT1A1 that could modify drug efficacy and xenobiotic metabolism. Some studies have investigated how differential metabolism of xenobiotic substances influences susceptibility to or protection from cancer in multiple sites. This review will focus primarily on the impact of SULT1A1 genetic variation on the response to anticancer therapeutic agents and subsequently how it relates to environmental and dietary exposure to both cancer-causing and cancer-preventative compounds.

Alcohol dehydrogenase-1B Arg47His polymorphism is associated with head and neck cancer risk in Asian: a meta-analysis

Head and neck cancers (HNCs) include cancers which arise in oral cavity, pharynx, and larynx. Recent studies have demonstrated that alcohol drinking is an established risk factor for HNC. The alcohol dehydrogenase-1B (ADH1B) plays a major role in the oxidized process of alcohol. To investigate the association of ADH1B Arg47His with HNC in Asian populations, we combined all available studies into a meta-analysis. A total of 2186 cases and 4488 controls were analyzed for this meta-analysis. We used odds ratios (ORs) to assess the strength of the association and 95% confidence intervals (CIs) to give a sense of the precision of the estimate. The ADH1B*47Arg allele was found to be associated with increased risk of HNC in Asians, with the pooled odds ratios (ORs) (Arg/Arg vs. Arg/His + His/His: OR = 2.35, 95% CI = 1.56-3.55, P < 0.0001) in all eight studies. In the subgroup analysis by alcohol consumption, the Arg/Arg vs. Arg/His + His/His genotype was found to be interacted with alcohol consumption, with the OR = 2.44, 95% CI = 1.85-3.20 among ever drinkers. Besides, no significant association was found in non-drinkers. This meta-analysis revealed that ADH1B Arg47His (rs1229984) polymorphism could increase the risk of HNC in Asians significantly.

Global lung cancer risk from PAH exposure highly depends on emission sources and individual susceptibility

The health impacts of polycyclic aromatic hydrocarbons (PAHs), the most concerning organic pollutants, depend not only on the locations and strengths of emission sources, but also on individual susceptibility. Moreover, trans-boundary transport makes them a global concern. In this study, a comprehensive analysis of the global health impacts of polycyclic aromatic hydrocarbons (PAHs) in ambient air is presented. Model resolution is critical in exposure modelling. Globally, incremental lifetime lung cancer risk (ILCR) induced by ambient PAH exposure is 3.1 × 10⁻⁵. If the individual susceptibility was not taken into consideration, the overall risk would be underestimated by 55% and the proportion of highly vulnerable population would be underestimated by more than 90%. Emphasizing on individual susceptibility, our study provides an instrumental revision of current risk assessment methodology. In terms of lung cancer risk, the most important sources are combustion of biomass fuels (40%) and fossil fuels (14%) in the residential/commercial sector, coke (13%) and aluminium (12%) production, and motor vehicles (9%). PAHs can travel long distance globally especially within the Eurasian continent. Still, the risk is dominantly contributed by local.

Glutathione-S-transferase polymorphism and acute lymphoblastic leukemia (ALL) in north Indian children: a case-control study and meta-analysis

Various studies on association of glutathione S-transferase (GST) polymorphisms and childhood acute lymphoblastic leukemia (ALL) have yielded conflicting results. We examined this association among north Indian children and conducted an updated meta-analysis to overcome sample size-related limitations. GSTM1, GSTP1 and GSTT1 genotypes in 100 children with ALL and 300 healthy controls were compared. GSTT1 null mutation (odds ratio (OR) 2.54, 95% confidence interval (CI) 1.50-4.32) and GSTP1 homozygous mutation (OR 3.13, 95%CI 1.48-6.59) were found to increase the risk of childhood ALL, while GSTM1 did not alter the risk. Meta-analysis included 22, 10 and 20 studies examining the association of childhood ALL with GSTM1, GSTP1 and GSTT1 genotypes, respectively. Only GSTM1 genotype (OR 1.29, 95%CI 1.10-1.62) was associated with increased risk in the overall analysis. However, both GSTM1 (OR 1.54, 95%CI 1.12-2.10) and GSTT1 (OR 1.63, 95%CI 1.32-1.99) null genotypes were associated with increased risk in Asian subjects. The risk of developing childhood ALL was not associated with GSTP1 genotype.

The effect of aristolochic acid I on expression of NAD(P)H:quinone oxidoreductase in mice and rats--a comparative study

Aristolochic acid is the cause of aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN) and their associated urothelial malignancies. Using Western blotting, we investigated the expression of

NAD(P)H

quinone oxidoreductase (NQO1), the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI) in mice and rats. In addition, the effect of AAI on the expression of the NQO1 protein and its enzymatic activity in these experimental animal models was examined. We found that NQO1 protein levels in cytosolic fractions isolated from liver, kidney and lung of mice differed from those expressed in these organs of rats. In mice, the highest levels of NQO1 protein and NQO1 activity were found in the kidney, followed by lung and liver. In contrast, the NQO1 protein levels and enzyme activity were lowest in rat-kidney cytosol, whereas the highest amounts of NQO1 protein and activity were found in lung cytosols, followed by those of liver. NQO1 protein and enzyme activity were induced in liver and kidney of AAI-pretreated mice compared with those of untreated mice. NQO1 protein and enzyme activity were also induced in rat kidney by AAI. Furthermore, the increase in hepatic and renal NQO1 enzyme activity was associated with AAI bio-activation and elevated AAI-DNA adduct levels were found in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, our results indicate that AAI can increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential.

PON1 Q192R polymorphism (rs662) is associated with childhood embryonal tumors

Genetic susceptibility and environment exposures are associated risk factors in carcinogenesis. Gene polymorphisms that decrease the activity of detoxifying carcinogen substances may modify the effect of exposures. We investigated whether the polymorphisms PON1 rs662 (Q192R), and PON1 rs854560 (L55M) would be associated with embryonal tumors in Brazilian children. Blood samples from 163 children with embryonal tumors and 342 as control group were genotyped by TaqMAN real-time PCR assays. Logistic regression was used to evaluate the association between the polymorphisms of cases and controls groups, adjusted by skin color and age strata. When all tumors were taken together, the presence of the PON1 rs662 (Q192R) variant genotype (RR) was associated with an increased risk of developing embryonal tumors (OR = 2.80, 95 % CI 1.12-7.02). The presence of at least one variant PON1 rs662 R allele increased the risk of developing Wilms´ Tumor although without statistical power. However, it was observed a significant association of PON1 rs662 (Q192R) variant genotype (RR) with retinoblastoma (OR = 4.08, 95 % CI 1.13-14.97), whereas the PON1 rs854560 (L55M) polymorphism was not associated with any tumor. These results indicate that PON1 polymorphisms may have an influence on the risk of developing embryonal tumors.

A meta-analysis of the association between NQO1 C609T variation and acute myeloid leukemia risk

Quinone oxidoreductase (NQO1) C609T polymorphisms have been implicated in acute myeloblastic leukemia (AML) risk, but previously published studies are inconsistent and recent meta-analyses have not been adequate. To derive a more precise estimation of the relationship, a meta-analysis was performed. Medline, PubMed, Embase, and Web of Science were searched. The quality of studies was evaluated by using the Newcastle-Ottawa Scale (NOS). Crude ORs with 95% CIs were used to assess the strength of association between the NQO1 C609T polymorphisms and AML risk. A total of 14 studies including 2,245 cases and 3,310 controls were involved in this meta-analysis. Overall, significantly elevated AML risk was associated with NQO1 C609T variant genotypes when all studies were pooled into the meta-analysis (TT vs. CC: OR = 1.44, 95% CI = 1.15-1.81; dominant model: OR = 1.35, 95% CI = 1.09-1.68). In the subgroup analysis by ethnicity, significantly increased risks were found for Asians (OR = 1.47, 95% CI = 1.13-1.93, P = 0.005, I(2) = 48.4%, P = 0.071 for heterogeneity). When stratified by studies of adults or children, statistically significantly elevated risks were found among adults (OR = 1.37, 95% CI = 1.06-1.76, P = 0.017, I(2) = 42.2%, P = 0.097 for heterogeneity). The accumulated evidence indicates that NQO1 C609T seems to confer a risk factor for AML among Asians and adults. Significant between-study heterogeneity was observed, thus more studies based on larger case-control population are required to further evaluate the role of NQO1 C609T polymorphism in AML.

Association between the polymorphism rs3217927 of CCND2 and the risk of childhood acute lymphoblastic leukemia in a Chinese population

CyclinD proteins, the ultimate recipients of mitogenic and oncogenic signals, play a crucial role in cell-cycle regulation. CyclinD2, one of the cyclinD family, is overexpressed in T-acute lymphoblastic leukemia (ALL) and B-cell chronic lymphocytic leukemia and involved in the pathogenesis of leukemias. Recent reports indicated that CCND2 polymorphisms are associated with human cancer risk, thusly we hypothesized that CCND2 gene polymorphisms may contribute to childhood ALL susceptibility. We selected the polymorphism rs3217927 located in the 3'UTR region of CCND2 to assess its associations with childhood ALL risk in a case-control study. A significant difference was found in the genotype distributions of rs3217927 polymorphism between cases and controls (P = 0.019) and homozygous GG genotype may be an increased risk factor for childhood ALL (adjusted OR  =  1.84, 95% CI  =  1.14 -2.99). Furthermore, this increased risk was more pronounced with GG genotype among high-risk ALL (adjusted OR  = 1.95, 95% CI  =  1.04-3.67), low-risk ALL (adjusted OR  =  2.09, 95% CI  =  1.13-3.87), B-phenotype ALL patients (adjusted OR  =  1.78, 95% CI  =  1.08-2.95) and T-phenotype ALL patients (adjusted OR  =  2.87, 95% CI  =  1.16-7.13). Our results provide evidence that CCND2 polymorphism rs3217927 may be involved in the etiology of childhood ALL, and the GG genotype of rs3217927 may modulate the genetic susceptibility to childhood ALL in the Chinese population. Further functional studies and investigations in larger populations should be conducted to validate our findings.