Genetic polymorphisms in the oxidative stress pathway and susceptibility to non-Hodgkin lymphoma

Aldo-keto reductase family 1 member A1 (AKR1A1) exerts a protective function in alcohol-associated liver disease by reducing 4-HNE accumulation and p53 activation

BACKGROUND

The development of alcohol-associated liver disease (ALD) is influenced by the amount and duration of alcohol consumption. The resulting liver damage can range from reversible stages, such as steatosis, steatohepatitis and alcoholic fibrosis, to the advanced and irreversible stage of cirrhosis. Aldo-keto reductase family 1 member A1 (AKR1A1) is a member of the aldo-keto reductase family that catalyzes the reduction of aldehyde groups to their corresponding alcohols in an NADPH-dependent manner. AKR1A1 was found to be downregulated in patients diagnosed with ALD. This study aims to interpret the protective effects of AKR1A1 on the development of ALD.

METHODS

A 5% alcohol-fed (AF) Akr1a1 knockout (Akr1a1-/-) mouse model and an AML12 hepatocyte model were used. The effects of AKR1A1 on liver function, inflammation, oxidative stress, lipid accumulation, and fibrosis were assessed by ELISA, western blotting, RT‒PCR, and a variety of histological staining methods in AF-induced wild-type (WT) and Akr1a1-/- mice compared to control liquid diet-fed (PF) WT and Akr1a1-/- mice.

RESULTS

The results demonstrated that AF-WT mice expressed higher levels of AKR1A1 than WT mice fed a control diet, and they did not show any noticeable liver steatosis. However, AF-Akr1a1-/- mice displayed a lower survival rate and more severe liver injury than AF-WT mice, as demonstrated by increased proinflammatory cytokines, oxidative stress, lipid accumulation, fibrosis, and reduced antioxidant enzymes in their livers. Additionally, elevated levels of 4-HNE and p53 phosphorylation were observed in AF-Akr1a1-/- mice, suggesting that the loss of AKR1A1 led to increased 4-HNE accumulation and subsequent activation of p53, which contributed to the progression of ALD. Furthermore, in AML12 hepatocytes, Akr1a1 knockdown aggravated oxidative stress and steatosis induced by palmitic acid/oleic acid (P/O) inflammation induced by lipopolysaccharide (LPS), and fibrosis induced by TGF-β1.

CONCLUSIONS

This loss-of-function study suggests that AKR1A1 plays a liver-protective role during chronic alcohol consumption by reducing the accumulation of 4-HNE and inhibiting 4-HNE-mediated p53 activation.

HSA Adductomics Reveals Sex Differences in NHL Incidence and Possible Involvement of Microbial Translocation

BACKGROUND

The higher incidence of non-Hodgkin lymphoma (NHL) in males is not well understood. Although reactive oxygen species (ROS) have been implicated as causes of NHL, they cannot be measured directly in archived blood.

METHODS

We performed untargeted adductomics of stable ROS adducts in human serum albumin (HSA) from 67 incident NHL cases and 82 matched controls from the European Prospective Investigation into Cancer and Nutrition-Italy cohort. Regression and classification methods were employed to select features associated with NHL in all subjects and in males and females separately.

RESULTS

Sixty seven HSA-adduct features were quantified by liquid chromatography-high-resolution mass spectrometry at Cys34 (n = 55) and Lys525 (n = 12). Three features were selected for association with NHL in all subjects, while seven were selected for males and five for females with minimal overlap. Two selected features were more abundant in cases and seven in controls, suggesting that altered homeostasis of ROS may affect NHL incidence. Heat maps revealed differential clustering of features between sexes, suggesting differences in operative pathways.

CONCLUSIONS

Adduct clusters dominated by Cys34 oxidation products and disulfides further implicate ROS and redox biology in the etiology of NHL. Sex differences in dietary and alcohol consumption also help to explain the limited overlap of feature selection between sexes. Intriguingly, a disulfide of methanethiol from enteric microbial metabolism was more abundant in male cases, thereby implicating microbial translocation as a potential contributor to NHL in males.

IMPACT

Only two of the ROS adducts associated with NHL overlapped between sexes and one adduct implicates microbial translocation as a risk factor.

Effect of Diet and Oxidative Stress in the Pathogenesis of Lymphoproliferative Disorders

Lymphomas are a heterogeneous group of pathologies that result from clonal proliferation of lymphocytes. They are classified into Hodgkin lymphoma and non-Hodgkin lymphoma; the latter develops as a result of B, T, or NK cells undergoing malignant transformation. It is believed that diet can modulate cellular redox state and that oxidative stress is implicated in lymphomagenesis by acting on several biological mechanisms; in fact, oxidative stress can generate a state of chronic inflammation through the activation of various transcription factors, thereby increasing the production of proinflammatory cytokines and causing overstimulation of B lymphocytes in the production of antibodies and possible alterations in cellular DNA. The purpose of our work is to investigate the results of in vitro and in vivo studies on the possible interaction between lymphomas, oxidative stress, and diet. A variety of dietary regimens and substances introduced with the diet that may have antioxidant and antiproliferative effects were assessed. The possibility of using nutraceuticals as novel anticancer agents is discussed; although the use of natural substances in lymphoma therapy is an interesting field of study, further studies are needed to define the efficacy of different nutraceuticals before introducing them into clinical practice.

Oxidative Stress and Inflammation in B-Cell Lymphomas

Mature lymphoid neoplasms arise de novo or by the transformation of more indolent lymphomas in a process that relies on the stepwise accumulation of genomic and transcriptomic alterations. The microenvironment and neoplastic precursor cells are heavily influenced by pro-inflammatory signaling, regulated in part by oxidative stress and inflammation. Reactive oxygen species (ROSs) are by-products of cellular metabolism able to modulate cell signaling and fate. Moreover, they play a crucial role in the phagocyte system, which is responsible for antigen presentation and the selection of mature B and T cells under normal conditions. Imbalances in pro-oxidant and antioxidant signaling can lead to physiological dysfunction and disease development by disrupting metabolic processes and cell signaling. This narrative review aims to analyze the impact of reactive oxygen species on lymphomagenesis, specifically examining the regulation of microenvironmental players, as well as the response to therapy for B-cell-derived non-Hodgkin lymphomas. Further research is needed to investigate the involvement of ROS and inflammation in the development of lymphomas, which may unravel disease mechanisms and identify innovative therapeutic targets.

Looking at denitrosylation to understand the myogenesis gone awry theory of rhabdomyosarcoma

S-nitrosylation of proteins is a nitric oxide (NO)-based post-translational modification of cysteine residues. By removing the NO moiety from S-nitrosothiol adducts, denitrosylases restore sulfhydryl protein pool and act as downstream tuners of S-nitrosylation signaling. Alterations in the S-nitrosylation/denitrosylation dynamics are implicated in many pathological states, including cancer ontogenesis and progression, skeletal muscle myogenesis and function. Here, we aim to provide and link different lines of evidence, and elaborate on the possible role of S-nitrosylation/denitrosylation signaling in rhabdomyosarcoma, one of the most common pediatric mesenchymal malignancy.

Clinical significance of oxidative stress for untreated patients with diffuse large B-cell lymphoma

Oxidative stress serves an important role in carcinogenesis. The present study investigated the clinical significance of oxidative stress as a prognostic factor for diffuse large B-cell lymphoma (DLBCL). The participants comprised 55 consecutive patients with DLBCL. A commercially available derivatives of reactive oxygen metabolites (d-ROMs) test kit was used to assess oxidant levels. Similarly, a commercially available biological antioxidant potential (BAP) test was used to assess antioxidant levels. The antioxidative/oxidative stress ratio was calculated as d-ROMs/BAP. The median serum concentration of d-ROMs was 425 µM. The levels of d-ROMs were significantly higher in patients with DLBCL than in healthy volunteers (P<0.01). The complete remission (CR) rates in patients with d-ROMs <425 and ≥425 µM were 81.5 and 85.7%, respectively [not significant (NS)]. The 3-year overall survival (OS) rates for patients with d-ROMs <425 and ≥425 µM were 67.2 and 72.0%, respectively (NS). The median BAP was 2,002 µM. The CR rates of patients with BAP <2,002 and ≥2,002 µM were 77.8 and 88.9%, respectively (NS). The 3-year OS rates of patients with BAP <2,002 and ≥2,002 µM were 60.9 and 75.9%, respectively (NS). No significant difference in the d-ROMs/BAP ratio was observed between groups. Multivariate analysis revealed that d-ROMs were an independent prognostic factor for progression-free survival.

A Review and Update with Perspective of Evidence that the Herbicide Glyphosate (Roundup) is a Cause of Non-Hodgkin Lymphoma

Glyphosate-based formulations (GBFs), such as Roundup, are the most heavily used herbicides in the world. In 2015, the International Agency for Research on Cancer (IARC) concluded that glyphosate and GBFs are probably carcinogenic to humans (group 2A), mainly for non-Hodgkin lymphoma (NHL). However, this finding has been controversial, and most pesticide regulatory agencies have not followed their lead. The purpose of this review was to examine the scientific literature linking exposure to glyphosate and GBFs to the development of NHL, with emphasis on new findings since publication of the IARC report. The epidemiologic studies provide ample evidence for an association between exposure to GBFs and an increased risk of NHL. Animal studies have shown that glyphosate is carcinogenic in rodents and causes NHL in mice. Mechanistic studies have demonstrated that glyphosate and GBFs are genotoxic to human lymphocytes, the normal cell of origin of NHL, both in vitro and in vivo. Genotoxic and other biological effects have also been shown in various animal and cell models with these agents even at low doses. A novel mechanism underlying the specificity of glyphosate for NHL, that is upregulation of the B-cell genome mutator enzyme activation-induced cytidine deaminase, has recently been demonstrated. These findings were evaluated holistically using the guidelines for evaluation of general causation set forth by Bradford Hill. This evaluation provides coherent and compelling evidence that glyphosate and GBFs are a cause of NHL in humans exposed to these agents. These findings should prompt new reviews by pesticide regulatory agencies around the world.

Pleiotropic Actions of Aldehyde Reductase (AKR1A)

We provide an overview of the physiological roles of aldehyde reductase (AKR1A) and also discuss the functions of aldose reductase (AKR1B) and other family members when necessary. Many types of aldehyde compounds are cytotoxic and some are even carcinogenic. Such toxic aldehydes are detoxified via the action of AKR in an NADPH-dependent manner and the resulting products may exert anti-diabetic and anti-tumorigenic activity. AKR1A is capable of reducing 3-deoxyglucosone and methylglyoxal, which are reactive intermediates that are involved in glycation, a non-enzymatic glycosylation reaction. Accordingly, AKR1A is thought to suppress the formation of advanced glycation end products (AGEs) and prevent diabetic complications. AKR1A and, in part, AKR1B are responsible for the conversion of d-glucuronate to l-gulonate which constitutes a process for ascorbate (vitamin C) synthesis in competent animals. AKR1A is also involved in the reduction of S-nitrosylated glutathione and coenzyme A and thereby suppresses the protein S-nitrosylation that occurs under conditions in which the production of nitric oxide is stimulated. As the physiological functions of AKR1A are currently not completely understood, the genetic modification of Akr1a could reveal the latent functions of AKR1A and differentiate it from other family members.

Exploiting S-nitrosylation for cancer therapy: facts and perspectives

S-nitrosylation, the post-translational modification of cysteines by nitric oxide, has been implicated in several cellular processes and tissue homeostasis. As a result, alterations in the mechanisms controlling the levels of S-nitrosylated proteins have been found in pathological states. In the last few years, a role in cancer has been proposed, supported by the evidence that various oncoproteins undergo gain- or loss-of-function modifications upon S-nitrosylation. Here, we aim at providing insight into the current knowledge about the role of S-nitrosylation in different aspects of cancer biology and report the main anticancer strategies based on: (i) reducing S-nitrosylation-mediated oncogenic effects, (ii) boosting S-nitrosylation to stimulate cell death, (iii) exploiting S-nitrosylation through synthetic lethality.

Associations between serum carotenoid levels and the risk of non-Hodgkin lymphoma: a case-control study

Limited studies have investigated the effects of serum carotenoids on the risk of non-Hodgkin lymphoma (NHL), and the findings have been inconclusive. This study aims to assess the association between serum total or specific carotenoid levels and NHL risk. This 1:1 matched, hospital-based case-control study enrolled 512 newly diagnosed (within 1 month) NHL patients and 512 healthy controls who were matched by age (±5 years) and sex in Urumqi, China. Serum carotenoid levels were measured by HPLC. Conditional logistic regression showed that higher serum total carotenoid levels and their subtypes (e.g. α-carotene, β-carotene, β-cryptoxanthin and lycopene) were dose-dependently associated with decreased NHL risk. The multivariable-adjusted OR and their 95 % CI for NHL risk for quartile 4 (v. quartile 1) were 0·31 (95 % CI 0·22, 0·48; Pfor trend < 0·001) for total carotenoids, 0·52 (95 % CI 0·33, 0·79; Pfor trend: 0·003) for α-carotene, 0·63 (95 % CI 0·42, 0·94; Pfor trend: 0·031) for β-carotene, 0·73 (95 % CI 0·49, 1·05; Pfor trend: 0·034) for β-cryptoxanthin and 0·51 (95 % CI 0·34, 0·75; Pfor trend: 0·001) for lycopene. A null association was observed between serum lutein + zeaxanthin and NHL risk (OR 0·89, 95 % CI 0·57, 1·38; Pfor trend: 0·556). Significant interactions were observed after stratifying according to smoking status, and inverse associations were more evident among current smokers than past or never smokers for total carotenoids, α-carotene and lycopene (Pfor heterogeneity: 0·047, 0·042 and 0·046). This study indicates that higher serum carotenoid levels might be inversely associated with NHL risk, especially among current smokers.

Protein Carbonylation and Lipid Peroxidation in Hematological Malignancies

Among the different mechanisms involved in oxidative stress, protein carbonylation and lipid peroxidation are both important modifications associated with the pathogenesis of several diseases, including cancer. Hematopoietic cells are particularly vulnerable to oxidative damage, as the excessive production of reactive oxygen species and associated lipid peroxidation suppress self-renewal and induce DNA damage and genomic instability, which can trigger malignancy. A richer understanding of the clinical effects of oxidative stress might improve the prognosis of these diseases and inform therapeutic strategies. The most common protein carbonylation and lipid peroxidation compounds, including hydroxynonenal, malondialdehyde, and advanced oxidation protein products, have been investigated for their potential effect on hematopoietic cells in several studies. In this review, we focus on the most important protein carbonylation and lipid peroxidation biomarkers in hematological malignancies, their role in disease development, and potential treatment implications.

Association of NCF2, NCF4, and CYBA Gene Polymorphisms with Rheumatoid Arthritis in a Chinese Population

Objective

Recent studies have focused on the special roles of NADPH-oxidase in multiple autoimmune diseases. Nevertheless, the association of genetic variation in NADPH-oxidase genes with rheumatoid arthritis (RA) was not extensively studied in a Chinese population. We performed this study to examine the association of NCF2, NCF4, and CYBA gene polymorphisms with RA susceptibility in a Chinese population.

Methods

Six single nucleotide polymorphisms (SNPs) (NCF2 rs10911363, NCF4 rs1883112, rs4821544, rs729749, CYBA rs3794624, and rs4673) were genotyped in a cohort composed of 593 RA patients and 596 normal controls. Improved multiple ligase detection reaction (iMLDR) was used for genotyping.

Results

We observed that NCF4 rs4821544 CT genotype and C allele frequencies in RA patients were significantly decreased when compared to controls (CT vs. TT: P = 0.043; C vs. T: P = 0.031), and rs4821544 polymorphism was significantly associated with an increased RA risk under the dominant model (TT vs. CT+CC: P = 0.031). Our results also indicated that rs729749 CT genotype frequency was significantly lower in RA patients than that in controls (CT vs. CC: P = 0.033). Moreover, the rs729749 CT genotype frequency was also significantly decreased in RA patients in males (CT vs. CC: P = 0.024). No significant association between NCF2 and CYBA gene polymorphisms and RA susceptibility was observed. There were significant associations between rs4821544 TT genotype and T allele frequencies and anti-CCP in male RA patients.

Conclusions

In summary, NCF4 rs4821544 and rs729749 polymorphisms might contribute to RA susceptibility, while NCF2 and CYBA gene polymorphisms were not associated with RA susceptibility.

Association of single nucleotide polymorphisms in the CYBA gene with coal workers' pneumoconiosis in the Han Chinese population

Coal workers' pneumoconiosis (CWP) is caused by long-term exposure to inhaled coal dust; it is likely influenced by the interaction between environmental factors and multiple susceptibility genes, such as the CYBA (cytochrome b-245α polypeptide) gene that has recently been identified to be involved in the genetic susceptibility for several pulmonary diseases. The aim of this case-control study was to explore the association between CYBA gene polymorphisms and the development of CWP in coal miners belonging to the Han ethnic group in China. Single nucleotide polymorphisms (SNPs) rs7195830, rs13306296, rs4673, rs9932581, and rs16966671 of the CYBA gene were analyzed in CWP patients (n = 652) and dust-exposed control subjects (n = 648) using the matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) on the Sequenom MassARRAY® platform (Sequenom, San Diego, CA, USA). Results from the present study showed a strong allele association between CWP patients and the CYBA SNP rs7195830 polymorphism (p < .001, OR = 1.550). Using the additive and the dominant model, the CYBA SNP rs7195830 polymorphism also showed significant associations with CWP patients (p < .001, OR = 1.621; p = .003, OR = 1.711, respectively). No statistically significant difference was demonstrated in either the allele or genotype frequencies of the other four examined SNPs (rs13306296, rs4673, rs9932581, and rs16966671) between the CWP group and dust-exposed control group (all p > .05). The present study is the first to have demonstrated an association between CYBA (rs7195830) polymorphism and the risk of developing CWP in subjects belong to the Han ethnic group in China and provides further clues for research into the pathogenesis of CWP.

New insights into redox homeostasis as a therapeutic target in B-cell malignancies

Purpose of review

The goal of this review is to summarize recent advances in our understanding of the regulation of redox homeostasis and the subtype-specific role of antioxidant enzymes in B-cell-derived malignancies. Furthermore, it presents selected prooxidative therapeutic strategies against B-cell neoplasms.

Recent findings

Recent reports have shown that the disturbed redox homeostasis in B-cell malignancies is regulated by cancer-specific signaling pathways and therefore varies between the individual subtypes. For instance, in a subtype of diffuse large B-cell lymphoma with increased oxidative phosphorylation, elevated reactive oxygen species are accompanied by higher levels of thioredoxin and glutathione and inhibition of either of these systems is selectively toxic to this subtype. In addition, growing number of small molecule inhibitors targeting antioxidant enzymes, such as auranofin, SK053, adenanthin, or decreasing glutathione level, such as imexon, buthionine sulfoximine, and L-cysteinase, trigger specific cytotoxic effects against B-cell malignancies. Lastly, attention is drawn to recent reports of effective treatment modalities involving prooxidative agents and interfering with redox homeostasis provided by stromal cells.

Summary

Recent findings reveal important differences in redox homeostasis within the distinct subsets of B-cell-derived malignancies that can be therapeutically exploited to improve existing treatment and to overcome drug resistance.

2,4-dichlorophenoxyacetic acid (2,4-D) and risk of non-Hodgkin lymphoma: a meta-analysis accounting for exposure levels

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most commonly used selective herbicides in the world. A number of epidemiology studies have found an association between 2,4-D exposure and non-Hodgkin lymphoma (NHL) but these results are inconsistent and controversial. A previous meta-analysis found no clear association overall but did not specifically examine high-exposure groups. We conducted a systematic review and meta-analysis of the peer-reviewed epidemiologic studies of the associations between 2,4-D and NHL, with a particular focus on high-exposure groups, and evaluations of heterogeneity, dose-response, and bias. A total of 12 observational studies, 11 case-control studies, and one cohort study, were included. The summary relative risk for NHL using study results comparing subjects who were ever versus never exposed to 2,4-D was 1.38 (95% confidence interval (CI), 1.07-1.77). However, in analyses focusing on results from highly exposed groups, the summary relative risk for NHL was 1.73 (95% CI, 1.10-2.72). No clear bias based on study design, exposure assessment methodology, or outcome misclassification was seen. Overall, these findings provide new evidence for an association between NHL and exposure to the herbicide 2,4-D.

Carotenoid intake and risk of non-Hodgkin lymphoma: a systematic review and dose-response meta-analysis of observational studies

Carotenoids may play a protective role in the development of non-Hodgkin lymphoma (NHL), but findings from epidemiological studies on the associations between carotenoid intake and NHL risk are inconsistent. We therefore performed a meta-analysis to systemically evaluate the associations. Eligible studies were identified by a search of PubMed, Web of Science, Embase, and article reference lists. We pooled risk estimates from individual studies using a random-effect model to quantify the associations between intakes of specific carotenoids and NHL risk. A total of 10 (7 case-control and 3 cohort) studies met our inclusion criteria. In the highest versus lowest analyses, intakes of alpha-carotene, beta-carotene, and lutein/zeaxanthin, but not lycopene or beta-cryptoxanthin, were associated with a significant reduced risk of NHL. The estimated summary relative risks (95% confidence intervals) for alpha-carotene, beta-carotene, and lutein/zeaxanthin were 0.87 (0.78-0.97), 0.80 (0.68-0.94), and 0.82 (0.69-0.97), respectively. Subgroup analyses showed that evidence supporting these protective associations was mostly based on studies with a case-control design. In addition, intakes of alpha-carotene and beta-carotene were associated with a significant decreased risk of diffuse large B-cell lymphoma, but not follicular lymphoma or small lymphocytic lymphoma/chronic lymphocytic leukemia. There was a significant inverse dose-response relationship between alpha-carotene intake and NHL risk (13% lower risk per 1000 μg/day increment of intake). In conclusion, our findings suggest that higher intakes of alpha-carotene, beta-carotene, and lutein/zeaxanthin might protect against NHL development. Further cohort studies with a control of plausible confounding are needed to confirm these associations.

Genetic variants involved in oxidative stress, base excision repair, DNA methylation, and folate metabolism pathways influence myeloid neoplasias susceptibility and prognosis

Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) share common features: elevated oxidative stress, DNA repair deficiency, and aberrant DNA methylation. We performed a hospital-based case-control study to evaluate the association in variants of genes involved in oxidative stress, folate metabolism, DNA repair, and DNA methylation with susceptibility and prognosis of these malignancies. To that end, 16 SNPs (one per gene: CAT, CYBA, DNMT1, DNMT3A, DNMT3B, GPX1, KEAP1, MPO, MTRR, NEIL1, NFE2F2, OGG1, SLC19A1, SOD1, SOD2, and XRCC1) were genotyped in 191 patients (101 MDS and 90 AML) and 261 controls. We also measured oxidative stress (reactive oxygen species/total antioxidant status ratio), DNA damage (8-hydroxy-2'-deoxyguanosine), and DNA methylation (5-methylcytosine) in 50 subjects (40 MDS and 10 controls). Results showed that five genes (GPX1, NEIL1, NFE2L2, OGG1, and SOD2) were associated with MDS, two (DNMT3B and SLC19A1) with AML, and two (CYBA and DNMT1) with both diseases. We observed a correlation of CYBA TT, GPX1 TT, and SOD2 CC genotypes with increased oxidative stress levels, as well as NEIL1 TT and OGG1 GG genotypes with higher DNA damage. The 5-methylcytosine levels were negatively associated with DNMT1 CC, DNMT3A CC, and MTRR AA genotypes, and positively with DNMT3B CC genotype. Furthermore, DNMT3A, MTRR, NEIL1, and OGG1 variants modulated AML transformation in MDS patients. Additionally, DNMT3A, OGG1, GPX1, and KEAP1 variants influenced survival of MDS and AML patients. Altogether, data suggest that genetic variability influence predisposition and prognosis of MDS and AML patients, as well AML transformation rate in MDS patients. © 2016 Wiley Periodicals, Inc.

Hodgkin-Reed-Sternberg cells in classical Hodgkin lymphoma show alterations of genes encoding the NADPH oxidase complex and impaired reactive oxygen species synthesis capacity

The membrane bound NADPH oxidase involved in the synthesis of reactive oxygen species (ROS) is a multi-protein enzyme encoded by CYBA, CYBB, NCF1, NCF2 and NCF4 genes. Growing evidence suggests a role of ROS in the modulation of signaling pathways of non-phagocytic cells, including differentiation and proliferation of B-cell progenitors. Transcriptional downregulation of the CYBB gene has been previously reported in cell lines of the B-cell derived classical Hodgkin lymphoma (cHL). Thus, we explored functional consequences of CYBB downregulation on the NADPH complex. Using flow cytometry to detect and quantify superoxide anion synthesis in cHL cell lines we identified recurrent loss of superoxide anion production in all stimulated cHL cell lines in contrast to stimulated non-Hodgkin lymphoma cell lines. As CYBB loss proved to exert a deleterious effect on the NADPH oxidase complex in cHL cell lines, we analyzed the CYBB locus in Hodgkin and Reed-Sternberg (HRS) cells of primary cHL biopsies by in situ hybridisation and identified recurrent deletions of the gene in 8/18 cases. Immunohistochemical analysis to 14 of these cases revealed a complete lack of detectable CYBB protein expression in all HRS cells in all cases studied. Moreover, by microarray profiling of cHL cell lines we identified additional alterations of NADPH oxidase genes including CYBA copy number loss in 3/7 cell lines and a significant downregulation of the NCF1 transcription (p=0.006) compared to normal B-cell subsets. Besides, NCF1 protein was significantly downregulated (p<0.005) in cHL compared to other lymphoma cell lines. Together this findings show recurrent alterations of the NADPH oxidase encoding genes that result in functional inactivation of the enzyme and reduced production of superoxide anion in cHL.

Sequence polymorphisms in the D-loop region of mitochondrial DNA and outcome of non-Hodgkin lymphoma

Accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) might be associated with cancer risk and disease outcome. We have identified 140 SNPs including 26 SNPs with frequency distribution of minor allele greater than 5% in a case-control study for non-Hodgkin lymphoma patients previously. In this study, we assessed the predictive power of D-loop SNPs in NHL patients. Five SNP sites were identified by log-rank test for statistically significant prediction of NHL survival in a univariate analysis. In an overall multivariate analysis, allele 16304 was identified as an independent predictor of NHL outcome. The survival time of NHL patients with 16304C was significantly shorter than that of patients with 16304T (relative risk, 0.513; 95% CI, 0.266-0.989; p = 0.046). The analysis of genetic polymorphisms in the mitochondrial D-loop can help identify subgroups of patients who are at a high risk of a poor disease outcome.

Single nucleotide polymorphisms in the mitochondrial displacement loop and age at onset of non-Hodgkin lymphoma

OBJECTIVE

Single nucleotide polymorphisms (SNPs) accumulated frequently in the mitochondrial displacement loop (D-loop) in many cancers. We had identified cancer risk-associated SNPs in the D-loop of non-Hodgkin lymphoma (NHL) patients previously, in this study, we investigated the association of age at onset and D-loop SNPs in NHL patients.

MATERIALS AND METHODS

The D-loop region of mtDNA was sequenced for 133 NHL patients recorded at the Fourth Hospital of Hebei Medical University. The Kaplan-Meier method was used to identify age at onset-associated SNPs in the D-loop of NHL patients. The Cox proportional hazards model was used to identify independent risk factors for age at onset.

RESULTS

The SNP sites of nucleotides 146C/T, 151T/C, 194T/C, 315C/C insert, 523Del/A, and 525Del/C were identified for their association with age at onset, by the logrank test. In an overall multivariate analysis, allele 146 (relative risk, 0.403; 95% confidence interval [CI]: 0.182-0.895) (P = 0.026), allele 151 (relative risk, 0.378; 95% CI: 0.165-0.868) (P = 0.022), and allele 315 (relative risk, 3.554; 95% CI: 1.344-9.400) (P = 0.011) were identified as independent predictors for age at onset in NHL patients.

CONCLUSION

SNPs in the D-loop can predict age at onset in NHL patients. Analysis of the D-loop SNPs can help identify NHL patient subgroups at high risk of early onset.

DNA repair deficiency as a susceptibility marker for spontaneous lymphoma in golden retriever dogs: a case-control study

There is accumulating evidence that an individual's inability to accurately repair DNA damage in a timely fashion may in part dictate a predisposition to cancer. Dogs spontaneously develop lymphoproliferative diseases such as lymphoma, with the golden retriever (GR) breed being at especially high risk. Mechanisms underlying such breed susceptibility are largely unknown; however, studies of heritable cancer predisposition in dogs may be much more straightforward than similar studies in humans, owing to a high degree of inbreeding and more limited genetic heterogeneity. Here, we conducted a pilot study with 21 GR with lymphoma, 20 age-matched healthy GR and 20 age-matched healthy mixed-breed dogs (MBD) to evaluate DNA repair capability following exposure to either ionizing radiation (IR) or the chemical mutagen bleomycin. Inter-individual variation in DNA repair capacity was evaluated in stimulated canine lymphoctyes exposed in vitro utilizing the G2 chromosomal radiosensitivity assay to quantify clastogen-induced chromatid-type aberrations (gaps and breaks). Golden retrievers with lymphoma demonstrated elevated sensitivity to induction of chromosome damage following either challenge compared to either healthy GR or MBD at multiple doses and time points. Using the 75(th) percentile of chromatid breaks per 1,000 chromosomes in the MBD population at 4 hours post 1.0 Gy IR exposure as a benchmark to compare cases and controls, GR with lymphoma were more likely than healthy GR to be classified as "sensitive" (odds ratio = 21.2, 95% confidence interval 2.3-195.8). Furthermore, our preliminary findings imply individual (rather than breed) susceptibility, and suggest that deficiencies in heritable factors related to DNA repair capabilities may be involved in the development of canine lymphoma. These studies set the stage for larger confirmatory studies, as well as candidate-based approaches to probe specific genetic susceptibility factors.

Identification of sequence polymorphisms in the D-loop region of mitochondrial DNA as a risk factor for non-Hodgkin lymphoma

Accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) may be associated with an increased cancer risk. We investigated the non-Hodgkin lymphoma (NHL) risk profile of D-loop SNPs in a case-control study. The minor alleles of nucleotides 73A/G, 263A/G, 315C/C insert were associated with a decreased risk for NHL. The minor alleles of the nucleotides 200G/A were specifically associated with the risk of diffuse large B-cell lymphoma, whereas the minor allele of nucleotides 16362C/T and 249Del/A was specifically associated with the decreased risk of T-cell lymphoma. In conclusion, SNPs in mtDNA are potential modifiers of NHL risk. The analysis of genetic polymorphisms in the mitochondrial D-loop can help identify subgroups of patients who are at a high risk of developing NHL.

Redox regulation of T-cell function: from molecular mechanisms to significance in human health and disease

Reactive oxygen species (ROS) are thought to have effects on T-cell function and proliferation. Low concentrations of ROS in T cells are a prerequisite for cell survival, and increased ROS accumulation can lead to apoptosis/necrosis. The cellular redox state of a T cell can also affect T-cell receptor signaling, skewing the immune response. Various T-cell subsets have different redox statuses, and this differential ROS susceptibility could modulate the outcome of an immune response in various disease states. Recent advances in T-cell redox signaling reveal that ROS modulate signaling cascades such as the mitogen-activated protein kinase, phosphoinositide 3-kinase (PI3K)/AKT, and JAK/STAT pathways. Also, tumor microenvironments, chronic T-cell stimulation leading to replicative senescence, gender, and age affect T-cell susceptibility to ROS, thereby contributing to diverse immune outcomes. Antioxidants such as glutathione, thioredoxin, superoxide dismutase, and catalase balance cellular oxidative stress. T-cell redox states are also regulated by expression of various vitamins and dietary compounds. Changes in T-cell redox regulation may affect the pathogenesis of various human diseases. Many strategies to control oxidative stress have been employed for various diseases, including the use of active antioxidants from dietary products and pharmacologic or genetic engineering of antioxidant genes in T cells. Here, we discuss the existence of a complex web of molecules/factors that exogenously or endogenously affect oxidants, and we relate these molecules to potential therapeutics.

Quantitative evaluation of aldo-keto reductase expression in hepatocellular carcinoma (HCC) cell lines

The involvement of aldo–keto reductases (AKRs) in tumorigenesis is widely reported, but their roles in the pathological process are not generally recognized due to inconsistent measurements of their expression. To overcome this problem, we simultaneously employed real-time PCR to examine gene expression and multiple reaction monitoring (MRM) of mass spectrometry (MS) to examine the protein expression of AKRs in five different hepatic cell lines. These include one relatively normal hepatic cell line, L-02, and four hepatocellular carcinoma (HCC) cell lines, HepG2, HuH7, BEL7402 and SMMC7721. The results of real-time PCR showed that expression of genes encoding the AKR1C family members rather than AKR1A and AKR1B was associated with tumor, and most of genes encoding AKRs were highly expressed in HuH7. Similar observations were obtained through MRM. Different from HuH7, the protein abundance of AKR1A and AKR1B was relatively consistent among the other four hepatic cell lines, while protein expression of AKR1C varied significantly compared to L-02. Therefore, we conclude that the abundant distribution of AKR1C proteins is likely to be associated with liver tumorigenesis, and the AKR expression status in HuH7 is completely different from other liver cancer cell lines. This study, for the first time, provided both overall and quantitative information regarding the expression of AKRs at both mRNA and protein levels in hepatic cell lines. Our observations put the previous use of AKRs as a biomarker into question since it is only consistent with our data from HuH7. Furthermore, the data presented herein demonstrated that quantitative evaluation and comparisons within a protein family at both mRNA and protein levels were feasible using current techniques.

GPX1 gene Pro200Leu polymorphism, erythrocyte GPX activity, and cancer risk

A meta-analysis was conducted to assess the effect of glutathione peroxidase1 (GPX1) gene Pro200Leu (rs1050450) polymorphism on cancer risk. A comprehensive search was performed to identify all studies on the association of GPX1 gene Pro200Leu polymorphism with cancer risk. The fixed or random effect pooled measure was selected based on homogeneity test among studies. Heterogeneity among studies was evaluated using the I (2). Potential sources of between-study heterogeneity were explored by meta-regression and the sensitivity analysis. Publication bias was estimated using Egger's linear regression test. 35 published articles with 36 results were identified involving 16,920 cases and 19,946 controls. Results from the articles that both obeyed Hardy-Weinberg equilibrium in controls and met high quality design, showed no significant association of GPX1 gene Pro200Leu polymorphism with cancer risk in any of dominant (OR = 1.05, 95 %CI = 0.98-1.12), recessive (OR = 1.04 (0.95-1.13), and TT versus CC (OR = 1.05, 95 %CI = 0.97-1.15) models, and the findings were consistent considering the stratified analysis by cancer type. However, multivariate-adjusted ORs from articles that both obeyed Hardy-Weinberg equilibrium in controls and met high quality design, showed a significant association considering dominant (OR = 1.22, 95 %CI = 1.06-1.41), TT versus CC (OR = 1.16, 95 %CI = 1.02-1.32) models, and a marginally significant association was found considering TC versus CC (OR = 1.11, 95 %CI = 0.99-1.25) model. And compared with the CC genotype, the erythrocyte GPX activity was significantly lower for TT genotype: the standardized mean difference (SMD) = -0.37, 95 %CI = (-0.624, -0.118), and CT genotype: SMD = -0.19, 95 %CI = (-0.37, -0.002). The association of GPX1 gene Pro200Leu polymorphism with cancer risk might be influenced by confounders.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.

Polymorphisms of DNA repair and oxidative stress genes in B-cell lymphoma patients

The purpose of the study was to investigate the possible association between ERCC2 rs28365048, ERCC5 rs17655, XRCC3 rs861539 and NOS2A rs2297518 polymorphisms with B-cell lymphoma. The study was conducted on 189 patients with CD20⁺ B-cell lymphoma and 193 controls. The genotype frequencies were compared in the patient and control groups using quantitative polymerase chain reaction, based on allelic discrimination analysis. Our results indicated that variation in NOS2A may be significant in B-cell lymphoma in a population ≥50 years old (OR=2.15; 95% CI, 1.17-3.92; P=0.013). No association was observed between variations in ERCC2, ERCC5, XRCC3 and B-cell lymphoma in the studied population. Our finding of an association between age and NOS2A polymorphisms in lymphoma is unique and requires additional studies. The results concerning ERCC2, ERCC5 and XRCC3 variations add additional data to studies on genetic polymorphisms in the DNA repair pathway.

Aiding and abetting roles of NOX oxidases in cellular transformation

NADPH oxidases of the NADPH oxidase (NOX) family are dedicated reactive oxygen species-generating enzymes that broadly and specifically regulate redox-sensitive signalling pathways that are involved in cancer development and progression. They act at specific cellular membranes and microdomains through the activation of oncogenes and the inactivation of tumour suppressor proteins. In this Review, we discuss primary targets and redox-linked signalling systems that are influenced by NOX-derived ROS, and the biological role of NOX oxidases in the aetiology of cancer.

Risk Factors of Follicular Lymphoma

INTRODUCTION: Non-Hodgkin Lymphoma (NHL) is a heterogeneous group of malignancies with over thirty different subtypes. Follicular lymphoma (FL) is the most common form of indolent NHL and the second most common form of NHL overall. It has morphologic, immunophenotypic and clinical features significantly different from other subtypes. Considerable effort has been devoted to the identification of risk factors for etiology and prognosis of FL. These risk factors may advance our understanding of the biology of FL and have an impact on clinical practice. AREAS COVERED: The epidemiology of NHL and FL is briefly reviewed. For FL etiology and prognosis separately, we review clinical, environmental and molecular (including genetic, genomic, epigenetic and others) risk factors suggested in the literature. EXPERT OPINION: A large number of potential risk factors have been suggested in recent studies. However, there is a lack of consensus, and many of the suggested risk factors have not been rigorously validated in independent studies. There is a need for large-scale, prospective studies to consolidate existing findings and discover new risk factors. Some of the identified risk factors are successful at the population level. More effective individual-level risk factors and models remain to be identified.

Genetic polymorphisms in oxidative stress pathway genes and modification of BMI and risk of non-Hodgkin lymphoma

BACKGROUND

Being overweight and obese increases oxidative stress in the body. To test the hypothesis that genetic variations in oxidative stress pathway genes modify the relationship between body mass index (BMI) and risk of non-Hodgkin lymphoma (NHL), we conducted a population-based case-control study in Connecticut women.

METHODS

Individuals who were overweight/obese (BMI ≥ 25) were compared with normal and underweight individuals (BMI < 25), and their risk of NHL stratified assuming a dominant allele model for each oxidative stress pathway single-nucleotide polymorphism.

RESULTS

Polymorphisms in AKR1A1, AKR1C1, AKR1C3, CYBA, GPX1, MPO, NCF2, NCF4, NOS1, NOS2A NOS3, OGG1, ATG9B, SOD1, SOD2, SOD3, RAC1, and RAC2 genes after false discovery rate adjustment did not modify the association between BMI and risk of NHL overall and histologic subtypes.

CONCLUSIONS

The results suggest that common genetic variations in oxidative stress genes do not modify the relationship between BMI and risk of NHL.

IMPACT

Studies of BMI and oxidative stress independently may elevate NHL risk, but this study suggests no interaction of the two risk factors. Future studies with larger study populations may reveal interactions.

Physical activity modifies the association between CYBA gene polymorphisms and small artery elasticity in a Chinese population

Emerging evidence suggests that increased superoxide production is responsible for a significant proportion of endothelial dysfunction. The relationship between variants of the CYBA gene and cardiovascular diseases is currently debated. In the present study, we investigated the influence of CYBA polymorphisms (rs1049255 and rs7195830) on arterial elasticity in a Chinese population. In the 2178 participants enrolled in the GaoYou study, we measured large artery elasticity (C1) and small artery elasticity (C2) non-invasively, genotyped the CYBA polymorphisms and calculated energy expenditure. The AA genotype of the rs1049255 polymorphism was associated with a lower C2 than were the GG/AG genotypes (5.31±0.11 vs. 5.52±0.06 ml mm Hg(-1) × 100; P=0.01). Further analyses revealed an interaction between CYBA polymorphisms and physical activity with respect to C2 (P=0.007 for rs1049255 and P=0.038 for rs7195830). In less physically active participants, the AA genotype of the rs1049255 polymorphism was associated with a significantly lower C2 than the GG/AG genotypes (4.69±0.16 vs. 5.26±0.19 ml mm Hg(-1) × 100; P=0.008). In physically active participants, the GG/AG genotypes of rs7195830 polymorphism were correlated with higher C2 values than the AA genotype (5.84±0.08 vs. 5.08±0.32 ml mm Hg(-1) × 100; P=0.049). Haplotype analyses revealed higher C2 values in rs1049255G-rs7195830G carriers (P=0.0015). In conclusion, the rs1049255 and rs7195830 polymorphisms of the CYBA gene were associated with C2 in a Chinese population; physical activity could modify this genetic effect.

Risk Factors of Non-Hodgkin Lymphoma

INTRODUCTION: Despite decades of intensive research, Non-Hodgkin Lymphoma (NHL) remains poorly understood and is largely incurable. NHL is a heterogeneous group of malignancies with multiple subtypes, each of which has distinct morphologic, immunophenotypic, and clinical features. Identifying the risk factors for NHL may improve our understanding of the underlying biological mechanisms and have an impact on clinical practice. AREAS COVERED: This article provides a review of several aspects of NHL, including epidemiology and subtype classification, clinical, environmental, genetic, and genomic risk factors identified for etiology and prognosis, and available statistical and bioinformatics tools for identification of genetic and genomic risk factors from the analysis of high-throughput studies. EXPERT OPINION: Multiple clinical and environmental risk factors have been identified. However, they have failed to provide practically effective prediction. Genetic and genomic risk factors identified from high-throughput studies have suffered a lack of reproducibility. The identification of genetic/genomic risk factors demands innovative statistical and bioinformatics tools. Although multiple analysis methods have been developed, there is still room for improvement. There is a critical need for well-designed, prospective, large-scale pangenomic studies.

A functional polymorphism in the NAD(P)H oxidase subunit CYBA is related to gene expression, enzyme activity, and outcome in non-Hodgkin lymphoma

NAD(P)H oxidase is a major endogenous source of reactive oxygen species (ROS). ROS may not only be involved in carcinogenesis but also in efficacy of chemotherapeutic agents like doxorubicin. By a comprehensive genotyping approach covering 48 genetic polymorphisms (single-nucleotide polymorphisms) in five subunits of phagocytic NAD(P)H oxidase, we asked whether they affect gene expression, enzymatic activity, and outcome of CHO(E)P chemotherapy. A highly consistent effect was observed for the CYBA 640A>G variant. In peripheral blood granulocytes of 125 healthy volunteers, the G allele of 640A>G was associated with lower NAD(P)H oxidase activity (P = 0.006). Moreover, the G allele was associated with lower mRNA and protein expression (both P = 0.02). Of clinical importance, the outcome of patients suffering from non-Hodgkin lymphoma and treated with CHO(E)P regimen was dependent on the CYBA 640A>G polymorphism. In an exploratory study (n = 401), carriers of 640GG had an event-free survival (EFS) risk ratio of 1.95 [95% confidence interval (95% CI), 1.31-2.90; P = 0.001] compared with 640AA. In a confirmatory set (n = 477), the risk ratios were 1.53 (1.04-2.25, P = 0.03). The complete set of 878 patients showed a relative risk of 1.72 (1.30-2.26) and 1.59 (1.14-2.21) for EFS and overall survival, respectively. Further molecular-biological experiments showed lower expression and reduced stability of transcripts with the G allele in lymphoblastoid cell lines. Transfection of allele-specific plasmids into HEK293 cells elicited lower activity for the G allele in a luciferase reporter gene construct. Thus, CYBA 640A>G was shown to be a functional polymorphism with possible consequences for patients receiving CHO(E)P chemotherapy and might have further implications for other ROS-mediated modalities.

Genetic polymorphisms in the metabolic pathway and non-Hodgkin lymphoma survival

Metabolic pathway enzymes, such as Cytochrome P450 (CYP), glutathione S-transferase (GST), and N-acetyltransferases (NAT) are involved in activation and detoxification of environmental carcinogens as well as drug metabolism. We hypothesized that the genetic variations in such metabolic pathways may affect NHL prognosis and survival. Follow-up information of 496 female NHL incident cases diagnosed during 1996-2000 in Connecticut were abstracted from the Connecticut Tumor Registry in 2008; survival analyses were conducted by comparing the Kaplan-Meier curves, and hazard ratios (HR) were computed from the Cox Proportional Hazard models adjusting for demographic and tumor characteristics which were suggested by previous studies to be determinants of NHL survival. We identified six SNPs from four metabolism genes (CYP2E1, GSTP1, GSTT1, and NAT1) that were associated with NHL survival. Specifically, polymorphisms in GSTT1 were associated with follicular lymphoma survival; and polymorphisms in CYP2E1, GSTP1, and NAT1 were associated with survival of chronic lymphocytic leukemia/small lymphocytic lymphoma. Our study suggests that genetic polymorphisms in metabolic pathways may help improve the prediction of NHL survival and prognosis.

Anomalous constitutive Src kinase activity promotes B lymphoma survival and growth

Background

Previously we have shown that B cell receptor (BCR) expression and B cell receptor signaling pathways are important for the basal growth of B lymphoma cells. In particular we have shown that the activation of Syk, a non-src family protein tyrosine kinase and the mitogen activated protein kinases (MAPK), ERK and JNK that mediate BCR signals are required for the constitutive growth of B lymphoma cells. Since src family protein tyrosine kinases (SFKs) like Lyn are known to be needed for the phosphorylation of BCR co-receptors, Ig-α and Ig-β, we hypothesized that one or more SFKs will be constitutively activated in B lymphoma cells and may be necessary for B lymphoma growth.

Results

Src kinase activity was found to be constitutively high in many murine and human B lymphoma cell lines and primary lymphoma samples. The specific pharmacological inhibitors of SFKs, PP1 and PP2 inhibited the proliferation of a number of both murine and human B lymphomas in a dose-dependent manner. Importantly, dasatinib (BMS-354825), an oral dual BCR-ABL and SFK specific inhibitor inhibited the growth of B lymphomas in the nanomolar range in vitro and strongly inhibited a mouse lymphoma growth in vivo. Among the SFKs, Lyn is predominantly phosphorylated and Lyn-specific small interfering RNA inhibited the growth of B lymphomas, supporting an important role for Lyn in B lymphoma growth. Suppression of SFK activity blocks BCR mediated signaling pathways. PMA or CpG can partially reverse the growth inhibition induced by SFK inhibition. Although blocking SFK activity inhibited the growth of a number of B lymphomas, some lymphomas such as SudHL-4, SudHL-6, OCI-Ly3 and OCI-Ly10 are more resistant due to an increased expression of the anti-apoptotic proteins Bcl-2 and Bcl-x_L.

Conclusions

These studies further support our concept that BCR signaling pathways are important for the continued growth of established B lymphoma cells. Some of the intermediates in this BCR pathway are potential immunotherapeutic targets. In particular, inhibition of SFK activity alone or in synergy with inhibition of the prosurvival Bcl-2 proteins holds promise in developing more effective treatments for B lymphoma patients.

Genetic variation in N-acetyltransferases 1 and 2, cigarette smoking, and risk of non-Hodgkin lymphoma

Cigarette smoke contains many carcinogens that are metabolically activated through xenobiotic metabolism by phase I and II enzymes, including N-acetyltransferases 1 and 2 (NAT1 and NAT2). We investigated non-Hodgkin lymphoma risk in general and by subtype in relation to NAT1 and NAT2 genotypes and cigarette smoking in a population-based case-control study in Connecticut. Of the 535 controls, 53.1% reported ever smoking, and of the 461 cases, 55.7% reported ever smoking. We found a two-fold increased risk of T-cell lymphoma among those possessing the NAT1*10 genotype compared to those with other NAT1 genotypes; including an OR of 2.0 (95% CI: 1.0-2.4) for those heterozygous or homozygous for NAT1*10 genotypes. Rapid acetylator NAT2 phenotype increased the risk of both T-cell lymphoma (OR = 3.2; 95% CI: 1.1-9.5) and marginal zone lymphoma (OR = 3.0; 95% CI: 1.0-8.7), though these results were based on a small number of cases. When smoking status and risk of NHL was stratified by NAT1 and NAT2 genotypes, an increased risk of NHL overall was observed in current (OR = 1.7; 95% CI: 1.2-2.4) smokers without the NAT1*10 genotype but not among smokers with the NAT1*10 genotype (p-interaction < 0.01). No association between history of cigarette smoking and risk of NHL overall was observed with any NAT2 genotype. Our results present modest evidence that acetylation rate is associated with risk of NHL for specific subtypes and that the NAT1*10 genotype is an "at-risk" allele. Additionally, our results suggest that the relationship between NHL and smoking status may be modified by common genetic variation in NAT1 but not NAT2. We conclude that these findings require replication in larger studies and ultimately in pooled analyses.

Genetic polymorphisms in nitric oxide synthase genes modify the relationship between vegetable and fruit intake and risk of non-Hodgkin lymphoma

Oxidative damage caused by reactive oxygen species and other free radicals is involved in carcinogenesis. It has been suggested that high vegetable and fruit intake may reduce the risk of non-Hodgkin lymphoma (NHL) as vegetables and fruit are rich in antioxidants. The aim of this study is to evaluate the interaction of vegetable and fruit intake with genetic polymorphisms in oxidative stress pathway genes and NHL risk. This hypothesis was investigated in a population-based case-control study of NHL and NHL histologic subtypes in women from Connecticut, including 513 histologically confirmed incident cases and 591 randomly selected controls. Gene-vegetable/fruit joint effects were estimated using unconditional logistic regression model. The false discovery rate method was applied to adjust for multiple comparisons. Significant interactions with vegetable and fruit intake were mainly found for genetic polymorphisms on nitric oxide synthase (NOS) genes among those with diffuse large B-cell lymphoma and follicular lymphoma. Two single nucleotide polymorphisms in the NOS1 gene were found to significantly modify the association between total vegetable and fruit intake and risk of NHL overall, as well as the risk of follicular lymphoma. When vegetables, bean vegetables, cruciferous vegetables, green leafy vegetables, red vegetables, yellow/orange vegetables, fruit, and citrus fruits were examined separately, strong interaction effects were narrowed to vegetable intake among patients with diffuse large B-cell lymphoma. Our results suggest that genetic polymorphisms in oxidative stress pathway genes, especially in the NOS genes, modify the association between vegetable and fruit intake and risk of NHL.

Genetic polymorphisms in glutathione S-transferases and cytochrome P450s, tobacco smoking, and risk of non-Hodgkin lymphoma

We investigated variation in glutathione S-transferases (GSTs) and cytochrome P450s (CYPs), and smoking in a population-based case-control study of NHL including 1,115 women. Although risk of NHL was not altered by variant polymorphisms in GSTs or CYPs, it was significantly changed for DLBCL when considered in conjunction with smoking behavior, though only in nonsmokers. An increased risk of DLBCL in nonsmokers was associated with the variant G allele for GSTP1 (OR = 1.6, 95% CI 1.0-2.3) and CYP1A1 (OR = 2.4; 95% CI 1.0-5.7), but a decreased risk for the variant G allele for CYP1B1 (OR = 0.6, 95% CI 0.4-1.0). Our results confer support investigation of the gene-environment interaction in a larger study population of DLBCL.

An intron 4 VNTR polymorphism of the endothelial nitric oxide synthase gene is associated with early-onset colorectal cancer

Endothelial-derived nitric oxide, which is produced by endothelial nitric oxide synthase (eNOS), may play an important role in colorectal carcinogenesis. However, the putative contribution of common eNOS genetic polymorphisms to colorectal cancer risk remains unknown. We genotyped 3 polymorphisms of eNOS (T-786C, G894T, and intron4b/a) in 727 colorectal adenocarcinoma cases and 736 age- and sex-matched healthy controls in Taiwan. Genotypes of the T-786C and G894T polymorphisms were determined by fluorescence polarization assays and the 27-bp variable number of tandem repeat (VNTR) polymorphism in intron 4 (intron4b/a) was analyzed by PCR. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Among younger participants (< or =60 yrs), the intron4a variant genotype was associated with a significantly increased risk of colorectal cancer, compared with the intron4bb genotype (OR = 1.60, 95% CI = 1.04-2.46). In addition, those young individuals bearing a greater number of high-risk genotypes (OR > 1, i.e., CT+TT for T-786C, ba+aa for intron4b/a, and GG for G894T) of eNOS had a higher colorectal cancer risk (p(trend) = 0.039). Compared with younger individuals without any putative high-risk genotypes, those with 3 high-risk genotypes had a significantly greater cancer risk (OR = 1.89, 95% CI = 1.04-3.43). Our results suggest that the eNOS intron4b/a polymorphism may contribute to early-onset colorectal cancer risk in the Taiwanese population.

Biomarkers of Psychological Stress in Health Disparities Research

Psychological stress can contribute to health disparities in populations that are confronted with the recurring stress of everyday life. A number of biomarkers have been shown to be affected by psychological stress. These biomarkers include allostatic load, which is a summary measure of the cumulative biological burden of the repeated attempts to adapt to daily stress. Allostatic load includes effects on the hypothalamic-pituitary axis, the sympathetic nervous system and the cardiovascular system. These in turn affect the immune system via bidirectional signaling pathways. Evidence is also building that psychological stress, perhaps via heightened inflammatory states, can increase oxidative stress levels and DNA damage. The inter-relationships of ethnicity, genotype, gene expression and ability to adequately mitigate stress response are just starting to be appreciated. The need to conduct these studies in disadvantaged populations is clear and requires methods to address potential logistical barriers. Biomarkers can help characterize and quantify the biological impact of psychological stress on the etiology of health disparities.

Association of single nucleotide polymorphisms in SOD2, XRCC1 and XRCC3 with susceptibility for the development of adverse effects resulting from radiotherapy for prostate cancer

The objective of this study was to determine whether an association exists between certain single nucleotide polymorphisms (SNPs), which have previously been linked with adverse normal tissue effects resulting from radiotherapy, and the development of radiation injury resulting from radiotherapy for prostate cancer. A total of 135 consecutive patients with clinically localized prostate cancer and a minimum of 1 year of follow-up who had been treated with radiation therapy, either brachytherapy alone or in combination with external-beam radiotherapy, with or without hormone therapy, were genotyped for SNPs in SOD2, XRCC1 and XRCC3. Three common late tissue toxicities were investigated: late rectal bleeding, urinary morbidity, and erectile dysfunction. Patients with the XRCC1 rs25489 G/A (Arg280His) genotype were more likely to develop erectile dysfunction after irradiation than patients who had the G/G genotype (67% compared to 24%; P=0.048). In addition, patients who had the SOD2 rs4880 T/C (Val16Ala) genotype exhibited a significant increase in grade 2 late rectal bleeding compared to patients who had either the C/C or T/T genotype for this SNP (8% compared to 0%; P=0.02). Finally, patients with the combination of the SOD2 rs4880 C/T genotype and XRCC3 rs861539 T/C (Thr241Met) genotype experienced a significant increase in grade 2 late rectal bleeding compared to patients without this particular genotypic arrangement (14% compared to 1%; P=0.002). These results suggest that SNPs in the SOD2, XRCC1 and XRCC3 genes are associated with the development of late radiation injury in patients treated with radiation therapy for prostate adenocarcinoma.

Bladder cancer risk and genetic variation in AKR1C3 and other metabolizing genes

Aromatic amines (AAs) and polycyclic aromatic hydrocarbons (PAHs) are carcinogens present in tobacco smoke and functional polymorphisms in NAT2 and GSTM1 metabolizing genes are associated with increased bladder cancer risk. We evaluated whether genetic variation in other candidate metabolizing genes are also associated with risk. Candidates included genes that control the transcription of metabolizing genes [aryl hydrocarbon receptor (AHR), AHRR and aryl hydrocarbon nuclear translocator (ARNT)] and genes that activate/detoxify AA or PAH (AKR1C3, CYP1A1, CYP1A2, CYP1B1, CYP3A4, EPHX1, EPHX2, NQO1, MPO, UGT1A4, SULT1A1 and SULT1A2). Using genotype data from 1150 cases of urothelial carcinomas and 1149 controls from the Spanish Bladder Cancer Study, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) adjusting for age, gender, region and smoking status. Based on a test for trend, we observed 10 non-redundant single-nucleotide polymorphisms (SNPs) in five genes (AKR1C3, ARNT, CYP1A1, CYP1B1 and SULT1A2) significantly associated with bladder cancer risk. We observed an inverse association with risk for the AKR1C3 promoter SNP rs1937845 [OR (95% CI) for heterozygote and homozygote variant compared with common homozygote genotype were 0.86 (0.70-1.06) and 0.74 (0.57-0.96), respectively; P for trend = 0.02]. Interestingly, genetic variation in this region has been associated with lung, non-Hodgkin lymphoma and prostate cancer risk. Analysis of additional SNPs to capture most (approximately 90%) of common genetic variation in AKR1C3 and haplotype walking analyses based on all AKR1C3 SNPs (n = 25) suggest two separate regions associated with bladder cancer risk. These results indicate that genetic variation in carcinogen-metabolizing genes, particularly AKR1C3, could be associated with bladder cancer risk.