Search

Background: Investigations of folate-mediated one-carbon metabolism (FOCM) genes and gene-nutrient interactions with respect to colorectal cancer (CRC) risk are limited to candidate polymorphisms and dietary folate. This study comprehensively investigated associations between genetic variants in FOCM and CRC risk and whether the FOCM nutrient status modified these associations.Methods: Two hundred eighty-eight candidate and tagging single-nucleotide polymorphisms (SNPs) in 30 FOCM genes were genotyped for 821 incident CRC case-control matched pairs in the Women's Health Initiative Observational Study cohort. FOCM biomarkers (red blood cell [RBC] folate, plasma folate, pyridoxal-5'-phosphate [PLP], vitamin B12, and homocysteine) and self-reported alcohol consumption were measured at the baseline. Conditional logistic regression was implemented; effect modification was examined on the basis of known enzyme-nutrient relations.Results: Statistically significant associations were observed between CRC risk and functionally defined candidate SNPs of methylenetetrahydrofolate dehydrogenase 1 (MTHFD1; K134R), 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR; P450R), and PR domain containing 2 with ZNF domain (PRDM2; S450N) and a literature candidate SNP of thymidylate synthase (TYMS; g.676789A>T; nominal P < .05). In addition, suggestive associations were noted for tagging SNPs in cystathionine-β-synthase (CBS), dihydrofolate reductase (DHFR), DNA (cytosine-5-)-methyltransferase 3β (DNMT3B), methionine adenosyltransferase I α (MAT1A), MTHFD1, and MTRR (nominal P < .05; adjusted P, not significant). Significant interactions between nutrient biomarkers and candidate polymorphisms were observed for 1) plasma/RBC folate and folate hydrolase 1 (FOLH1), paraoxonase 1 (PON1), transcobalamin II (TCN2), DNMT1, and DNMT3B; 2) plasma PLP and TYMS TS3; 3) plasma B12 and betaine-homocysteine S-methyltransferase 2 (BHMT2); and 4) homocysteine and methylenetetrahydrofolate reductase (MTHFR) and alanyl-transfer RNA synthetase (AARS).Conclusions: Genetic variants in FOCM genes are associated with CRC risk among postmenopausal women. FOCM nutrients continue to emerge as effect modifiers of genetic influences on CRC risk. [ABSTRACT FROM AUTHOR]

Introduction: Maintenance of normal weight and higher levels of physical activity are associated with a reduced risk of several types of cancer. Because genomic instability is regarded as a hallmark of cancer development, one proposed mechanism is improvement of DNA repair function. We investigated links between dietary weight loss, exercise, and strand break rejoining in an ancillary study to a randomized-controlled trial. Methods: Overweight/obese postmenopausal women (n = 439) were randomized to the following: a) reduced calorie weight loss diet ("diet," n = 118), b) moderate- to vigorous-intensity aerobic exercise ("exercise," n = 117), c) a combination ("diet + exercise," n = 117), or d) control (n = 87). The reduced calorie diet had a 10% weight loss goal. The exercise intervention consisted of 45 min of moderate to vigorous aerobic activity 5 d⋅wk-1 for 12 months. DNA repair capacity was measured in a subset of 226 women at baseline and 12 months from cryopreserved peripheral mononuclear cells using the comet assay. Anthropometric and body composition measures were performed at baseline and 12 months. Results: DNA repair capacity did not change significantly with any of the 12-month interventions compared with control; there were also no significant changes when stratified by changes in body composition or aerobic fitness (...O2max). At baseline, DNA repair capacity was positively associated with weight, body mass index, and fat mass (r = 0.20, P= 0.003; r = 0.19, P = 0.004; r = 0.13, P = 0.04, respectively) and inversely with lean body mass (r = -0.14, P = 0.04). Conclusion: In conclusion, DNA repair capacity in cryopreserved PBMCs (Comet Assay) did not change with dietary weight loss or exercise interventions in postmenopausal women within a period of 12 months. Other assays that capture different facets of DNA repair function may be needed. [ABSTRACT FROM AUTHOR]

Background Regular aspirin use reduces colon adenoma and carcinoma incidence. UDP-glucuronosyltransferases (UGT) are involved in aspirin metabolism and clearance, and variant alleles in UGT1A6 have been shown to alter salicylic acid metabolism and risk of colon neoplasia. Methods In a randomized, cross-over, placebo-controlled trial of 44 healthy men and women, homozygous for UGT1A6*1 or UGT1A6*2, we explored differences between global epithelial and stromal expression, using Affymetrix U133 + 2.0 microarrays and tested effects of 60-day aspirin supplementation (325 mg/d) on epithelial and stromal gene expression and colon prostaglandin E2 (PGE2) levels. Results No statistically significant differences in gene expression were observed in response to aspirin or UGT1A6 genotype, but tissue PGE2 levels were lower with aspirin compared to placebo (p <0.001). Transcripts differentially expressed between epithelium and stroma (N = 4916, P <0.01, false discovery rate <0.001), included a high proportion of genes involved in cell signaling, cellular movement, and cancer. Genes preferentially expressed in epithelium were involved in drug and xenobiotic metabolism, fatty acid and lipid metabolism, apoptosis signaling, and ion transport. Genes preferentially expressed in stroma included those involved in inflammation, cellular adhesion, and extracellular matrix production. Wnt-Tcf4 pathway genes were expressed in both epithelium and stroma but differed by subcellular location. Conclusions These results suggest that, in healthy individuals, subtle effects of aspirin on gene expression in normal colon tissue are likely overwhelmed by inter-individual variability in microarray analyses. Differential expression of critical genes between colonic epithelium and stroma suggest that these tissue types need to be considered separately. [ABSTRACT FROM AUTHOR]

This study comprehensively assessed whether variation in prostaglandin synthesis and related pathways influences CRC risk by examining associations between 192 SNPs and two functional VNTRs within 17 candidate genes.Although use of non-steroidal anti-inflammatory drugs (NSAIDs) generally decreases colorectal cancer (CRC) risk, inherited genetic variation in inflammatory pathways may alter their potential as preventive agents. We investigated whether variation in prostaglandin synthesis and related pathways influences CRC risk in the Colon Cancer Family Registry by examining associations between 192 single nucleotide polymorphisms (SNPs) and two variable nucleotide tandem repeats (VNTRs) within 17 candidate genes and CRC risk. We further assessed interactions between these polymorphisms and NSAID use on CRC risk. Using a case-unaffected-sibling-control design, this study included 1621 primary invasive CRC cases and 2592 sibling controls among Caucasian men and women aged 18–90. After adjustment for multiple comparisons, two intronic SNPs were associated with rectal cancer risk: rs11571364 in ALOX12 [ORhet/hzv = 1.87, 95% confidence interval (CI) = 1.19–2.95, P = 0.03] and rs45525634 in PTGER2 (ORhet/hzv = 0.49, 95% CI = 0.29–0.82, P = 0.03). Additionally, there was an interaction between NSAID use and the intronic SNP rs2920421 in ALOX12 on risk of CRC (P = 0.03); among those with heterozygous genotypes, risk was reduced for current NSAID users compared with never or former users (ORhet = 0.60, 95% CI = 0.45–0.80), though not among those with homozygous wild-type or variant genotypes. The results of this study suggest that genetic variation in ALOX12 and PTGER2 may affect the risk of rectal cancer. In addition, this study suggests plausible interactions between NSAID use and variants in ALOX12 on CRC risk. These results may aid in the development of genetically targeted cancer prevention strategies with NSAIDs. [ABSTRACT FROM AUTHOR]

Purpose: Approximately 10–30 % of colorectal cancers exhibit somatic mutations in the phosphoinositide-3-kinase, catalytic, alpha polypeptide gene ( PIK3CA). We evaluated the relationship between PIK3CA mutation status and demographic factors, lifestyle factors, and other tumor characteristics and the relationship between PIK3CA mutation status and colorectal cancer survival. Methods: The population-based study included postmenopausal women with invasive colorectal cancer diagnosed between 1998 and 2002 in Western Washington State. Participants were interviewed, and tumor specimens were tested for PIK3CA mutations in exons 9 and 20 hotspots, KRAS exon 2 mutations, BRAF p.V600E mutation, and microsatellite instability. We used Cox regression to evaluate the association between PIK3CA mutation status and disease-specific and overall survival. Stratified analyses were conducted by KRAS mutation status. Results: PIK3CA mutations were evident in approximately 13 % of cases ( N = 35). Women with PIK3CA-mutated colorectal cancer were significantly more likely than those with PIK3CA wild-type disease to be non-white, to have proximal colon cancer, and to have KRAS-mutated tumors ( p < 0.05). In Cox proportional hazards regression analyses, overall survival was poorer, although not statistically significantly so, for women with PIK3CA-mutated versus wild-type colorectal cancer (hazard ratio = 1.74, 95 % confidence interval 0.86–3.50). This association between PIK3CA mutation status and survival was evident only when analyses were restricted to cases without somatic KRAS mutations (hazard ratio = 2.94, 95 % confidence interval 1.12–7.73). Conclusions: PIK3CA-mutated colorectal cancer appears to have a distinct epidemiologic profile that is of clinical significance. Women with PIK3CA-mutated colorectal cancer experience a poorer prognosis than those with PIK3CA wild-type disease. [ABSTRACT FROM AUTHOR]

Abstract: During their development from progenitors, lymphocytes make a series of cell fate decisions. These decisions reflect and require changes in overall programs of gene expression. To maintain cellular identity, programs of gene expression must be iterated through mitosis in a heritable manner by epigenetic processes, which include DNA methylation, methyl-CpG- binding proteins, histone modifications, transcription factors and higher order chromatin structure. Current evidence is consistent with the notion that DNA methylation acts in concert with other epigenetic processes to limit the probability of aberrant gene expression and to stabilize, rather than to initiate, cell fate decisions. In particular, DNA methylation appears to be a non-redundant repressor of CD8 expression in TCR-γδ T cells and Th2 cytokine expression in Th1 and CD8 T cells, and is required to enforce clonally restricted Ly49 and KIR gene expression in NK cells. However, most of our knowledge is derived from in vitro studies, and the importance of DNA methylation in memory cell lineage fidelity in vivo remains to be shown convincingly. [Copyright &y& Elsevier]

How T cells regulate interleukin 4 (IL-4) expression is not completely understood. We show here that single-positive thymocytes express IL-4, but attenuate GATA-3 expression, recruit DNA methyltransferases (Dnmts) to the Il4-Il13 locus and downregulate IL-4 expression as they mature into T cells. Type 2 polarization blocks Dnmt1 recruitment, enhances histone H3 Lys4 methylation (indicative of accessible chromatin) and initiates DNA demethylation of the locus. Dnmt1-/- CD4 and CD8 T cells derepress IL-4 expression considerably, demethylate DNA and increase H3 Lys4 methylation without affecting GATA-3 expression, demonstrating that Dnmt1 and DNA methylation are essential for proper Il4 regulation. These results indicate that Dnmts, DNA and histone methylation, and transcription factors 'collaborate' to determine appropriate Il4 expression patterns. [ABSTRACT FROM AUTHOR]

During their development, T lymphocytes make sequential cell fate choices: T rather than B lymphocytes, then TCRoαβ or TCRγδ, CD4 or CDS, and Th1 or Th2 lineage. These fate choices require the initiation of new programs of gene expression, and once initiated, these programs must be faithfully propagated in a heritable manner from parental cells to their progeny. With the exception of the T cell receptor, these changes in gene expression occur without a change in information encoded directly in the DNA sequence. Rather, these heritable programs of gene expression are imposed, at least in part, epigenetically through changes in chromatin structure and DNA methylation, allowing T cells to tune the threshold for expression of specific genes. [ABSTRACT FROM AUTHOR]

Comments on studies on histone methyltransferase G9a. Recruitment of histone methyltransferase G9a to a promoter gene encoding human interferon-beta by a DNA-binding protein; Targeting of histone methyltransferase G9a to a specific locus to mediate transcriptional repression.

Integrating data from a large genome-wide association study, a prospective clinical cohort, and a laboratory-based functional assay, this study provides evidence that germline variants in the tumor suppressor CDKN2A may influence susceptibility for esophageal adenocarcinoma, an increasingly important cancer with poor survival.Incidence of esophageal adenocarcinoma (EA) in Western countries has increased markedly in recent decades. Although several risk factors have been identified for EA and its precursor, Barrett’s esophagus (BE), including reflux, Caucasian race, male gender, obesity, and smoking, less is known about the role of inherited genetic variation. Frequent somatic mutations in the tumor suppressor genes CDKN2A and TP53 were recently reported in EA tumors, while somatic alterations at 9p (CDKN2A) and 17p (TP53) have been implicated as predictors of progression from BE to EA. Motivated by these findings, we used data from a genome-wide association study of 2515 EA cases and 3207 controls to analyze 37 germline single nucleotide polymorphisms at the CDKN2A and TP53 loci. Three CDKN2A polymorphisms were nominally associated (P < 0.05) with reduced risk of EA: rs2518720 C>T [intronic, odds ratio 0.90, P = 0.0121, q = 0.3059], rs3088440 G>A (3′UTR, odds ratio 0.84, P = 0.0186, q = 0.3059), and rs4074785 C>T (intronic, odds ratio 0.85, P = 0.0248, q = 0.3059). None of the TP53 single nucleotide polymorphisms reached nominal significance. Two of the CDKN2A variants identified were also associated with reduced risk of progression from BE to EA, when assessed in a prospective cohort of 408 BE patients: rs2518720 (hazard ratio 0.57, P = 0.0095, q = 0.0285) and rs3088440 (hazard ratio 0.34, P = 0.0368, q = 0.0552). In vitro functional studies of rs3088440, a single nucleotide polymorphism located in the seed sequence of a predicted miR-663b binding site, suggested a mechanism whereby the G>A substitution may attenuate miR-663b-mediated repression of the CDKN2A transcript. This study provides the first evidence that germline variation at the CDKN2A locus may influence EA susceptibility. [ABSTRACT FROM AUTHOR]

Vaccine development against tuberculosis (TB) is based on the induction of adaptive immune responses endowed with long-term memory against mycobacterial antigens. Memory B and T cells initiate a rapid and robust immune response upon encounter with Mycobacterium tuberculosis, thus achieving long-lasting protection against infection. Recent studies have shown, however, that innate immune cell populations such as myeloid cells and NK cells also undergo functional adaptation after infection or vaccination, a de facto innate immune memory that is also termed trained immunity. Experimental and epidemiological data have shown that induction of trained immunity contributes to the beneficial heterologous effects of vaccines such as bacille Calmette-Guérin (BCG), the licensed TB vaccine. Moreover, increasing evidence argues that trained immunity also contributes to the anti-TB effects of BCG vaccination. An interaction among immunological signals, metabolic rewiring, and epigenetic reprogramming underlies the molecular mechanisms mediating trained immunity in myeloid cells and their bone marrow progenitors. Future studies are warranted to explore the untapped potential of trained immunity to develop a future generation of TB vaccines that would combine innate and adaptive immune memory induction. [ABSTRACT FROM AUTHOR]

Background Metallothionein (MT) proteins play critical roles in the physiological handling of both essential (Cu and Zn) and toxic (Cd) metals. MT expression is regulated by metal-regulatory transcription factor 1 (MTF1). Hence, genetic variation in the MT gene family and MTF1 might influence excretion of these metals. Methods 321 women were recruited in Seattle, WA and Las Cruces, NM and provided demographic information, urine samples for measurement of metal concentrations by mass spectrometry and creatinine, and blood or saliva for extraction of DNA. Forty-one single nucleotide polymorphisms (SNPs) within the MTF1 gene region and the region of chromosome 16 encoding the MT gene family were selected for genotyping in addition to an ancestry informative marker panel. Linear regression was used to estimate the association of SNPs with urinary Cd, Cu, and Zn, adjusted for age, urinary creatinine, smoking history, study site, and ancestry. Results Minor alleles of rs28366003 and rs10636 near the MT2A gene were associated with lower urinary Cd, Cu, and Zn. Minor alleles of rs8044719 and rs1599823, near MT1A and MT1B, were associated with lower urinary Cd and Zn, respectively. Minor alleles of rs4653329 in MTF1 were associated with lower urinary Cd. Conclusions These results suggest that genetic variation in the MT gene region and MTF1 influences urinary Cd, Cu, and Zn excretion. [ABSTRACT FROM AUTHOR]

The negative health effects of shift work, including carcinogenesis, may be mediated by changes in DNA methylation, particularly in the circadian genes. Using the Infinium HumanMethylation450 Bead Array (Illumina, San Diego, CA), we compared genome-wide methylation between 65 actively working dayshift workers and 59 actively working nightshift workers in the healthcare industry. A total of 473 800 loci, including 391 loci across the 12 core circadian genes, were analyzed to identify methylation markers associated with shift work status using linear regression models adjusted for gender, age, body mass index, race, smoking status and leukocyte cell profile as measured by flow cytometry. Analyses at the level of gene, CpG island and gene region were also conducted. To account for multiple comparisons, we controlled the false discovery rate (FDR ≤0.05). Significant differences between nightshift and dayshift workers were found at 16 135 of 473 800 loci, across 3769 of 20 164 genes, across 7173 of 22 721 CpG islands and across 5508 of 51 843 gene regions. For each significant loci, gene, CpG island or gene region, average methylation was consistently found to be decreased among nightshift workers compared to dayshift workers. Twenty-one loci located in the circadian genes were also found to be significantly hypomethylated among nightshift workers. The largest differences were observed for three loci located in the gene body of PER3. A total of nine significant loci were found in the CSNK1E gene, most of which were located in a CpG island and near the transcription start site of the gene. Methylation changes in these circadian genes may lead to altered expression of these genes which has been associated with cancer in previous studies. Gene ontology enrichment analysis revealed that among the significantly hypomethylated genes, processes related to host defense and immunity were represented. Our results indicate that the health effects of shift work may be mediated by hypomethylation of a wide variety of genes, including those related to circadian rhythms. While these findings need to be followed-up among a considerably expanded group of shift workers, the data generated by this study supports the need for future targeted research into the potential impacts of shift work on specific carcinogenic mechanisms. [ABSTRACT FROM AUTHOR]

BACKGROUND Recurrence and toxicity occur commonly among patients with rectal cancer who are treated with 5-fluorouracil (5-FU). The authors hypothesized that genetic variation in folate-metabolizing genes could play a role in interindividual variability. The objective of the current study was to evaluate the associations between genetic variants in folate-metabolizing genes and clinical outcomes among patients with rectal cancer treated with 5-FU. METHODS The authors investigated 8 functionally significant polymorphisms in 6 genes (methylenetetrahydrofolate reductase [ MTHFR] [C677T, A1298C], SLC19A1 [G80A], SHMT1 [C1420T], dihydrofolate reductase [ DHFR] [Del19bp], TS 1494del,and TSER) involved in folate metabolism in 745 patients with TNM stage II or III rectal cancer enrolled in a phase 3 adjuvant clinical trial of 3 regimens of 5-FU and radiotherapy (INT-0144 and SWOG 9304). RESULTS There were no statistically significant associations noted between polymorphisms in any of the genes and overall survival, disease-free survival (DFS), and toxicity in the overall analyses. Nevertheless, there was a trend toward worse DFS among patients with the variant allele of MTHFR C677T compared with wild-type, particularly in treatment arm 2, in which patients with the MTHFR C677T TT genotype had worse overall survival (hazards ratio, 1.76; 95% confidence interval, 1.06-2.93 [ P = .03]) and DFS (hazards ratio, 1.84; 95% confidence interval, 1.12-3.03 [ P = .02]) compared with those with homozygous wild-type. In addition, there was a trend toward reduced hematological toxicity among patients with variants of SLC19A1 G80A in treatment arm 1 ( P for trend, .06) and reduced esophagitis/stomatitis noted among patients with variants of TSER in treatment arm 3 ( P for trend, .06). CONCLUSIONS Genetic variability in folate-metabolizing enzymes was found to be associated only to a limited degree with clinical outcomes among patients with rectal cancer treated with 5-FU. Cancer 2014;120:3329-3337. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]

Background: MicroRNAs (miRNAs) are regulatory RNAs, stable in circulation, and implicated in colorectal cancer (CRC) etiology and progression. Therefore they are promising as early detection biomarkers of colorectal neoplasia. However, many circulating miRNAs are highly expressed in blood cells, and therefore may not be specific to colorectal neoplasia. Methods: We selected 7 miRNA candidates with previously reported elevated expression in adenoma tissue but low expression in blood cells (“rare” miRNAs), 2 previously proposed as adenoma biomarkers, and 3 implicated in CRC. We conducted a colonoscopy-based case-control study including 48 polyp-free controls, 43 advanced adenomas, 73 non-advanced adenomas, and 8 CRC cases. miRNAs from plasma were quantified by qRT-PCR. Correlations between miRNA expression levels, adjusted for age and sex, were assessed. We used polytomous logistic regression to estimate odds ratios (ORs) and 95% confidence intervals quantifying the association between expression levels of miRNAs and case groups. We also conducted nonparametric receiver operating characteristic (ROC) analyses and estimated area under the curve (AUC). Results: miRNAs with high expression levels were statistically significantly correlated with one another. No miRNAs were significantly associated with non-advanced or advanced adenomas. Strong (ORs >5) and significant associations with CRC were observed for 6 miRNA candidates, with corresponding AUCs significantly >0.5. Conclusions: These candidate miRNAs, assayed by qRT-PCR, are probably unsuitable as blood-based adenoma biomarkers. Strong associations between miRNAs and CRC were observed, but primarily with miRNAs highly expressed in blood cells. These results suggest that rare miRNAs will require new detection methods to serve as circulating biomarkers of adenomas. [ABSTRACT FROM AUTHOR]

We conducted a case-control study of the association between subsets of colorectal polyps, including adenomas and serrated polyps, and single-nucleotide polymorphisms (SNPs) related to colorectal cancer through prior genome-wide association studies (GWAS). Participants were enrollees in the Group Health Cooperative (Seattle, Washington) aged 24–79 years who received a colonoscopy from 1998 to 2007, donated a buccal or blood sample, and completed a structured questionnaire. We performed genotyping of 13 colorectal cancer susceptibility SNPs. Polytomous logistic regression models were used to estimate odds ratios and 95% confidence intervals for associations between polyps and the colorectal cancer risk allele for each SNP under a log-additive model. Analyses included 781 controls, 489 cases with adenoma, 401 cases with serrated polyps, and 188 cases with both polyp types. The following SNPs were associated with advanced adenomas: rs10936599, rs10795668, rs16892766, and rs9929218 (P < 0.05). For nonadvanced adenomas and for serrated polyps overall, only rs961253 was statistically significant (P < 0.05). These associations were in the same directions as those in prior colorectal cancer GWAS. No SNP was significantly associated with hyperplastic polyps, and only rs6983267 was significantly associated with sessile serrated polyps, but this association was opposite of that found in colorectal cancer GWAS. Our results suggest that the association between colorectal cancer susceptibility SNPs and colorectal polyps varies by polyp type. [ABSTRACT FROM PUBLISHER]

Folate-mediated one-carbon metabolism is essential for DNA synthesis, repair, and methylation. Perturbations in one-carbon metabolism have been implicated in increased risk of some cancers and may also affect inflammatory processes. We investigated these interrelated pathways to understand their relation. The objective was to explore associations between inflammation and biomarkers of nutritional status and one-carbon metabolism. In a cross-sectional study in 1976 women selected from the Women's Health Initiative Observational Study, plasma vitamin B-6 [pyridoxal-5'-phosphate (PLP)], plasma vitamin B-12, plasma folate, and RBC folate were measured as nutritional biomarkers; serum C-reactive protein (CRP) and serum amyloid A (SAA) were measured as biomarkers of inflammation; and homocysteine and cysteine were measured as integrated biomarkers of one-carbon metabolism. Student's t, chi-square, and Spearman rank correlations, along with multiple linear regressions, were used to explore relations between biomarkers; additionally, we tested stratification by folic acid fortification period and multivitamin use. With the use of univariate analysis, plasma PLP was the only nutritional biomarker that was modestly significantly correlated with serum CRP and SAA (ρ = -0.22 and -0.12, respectively; P < 0.0001). Homocysteine (µmol/L) showed significant inverse correlations with all nutritional biomarkers (ranging from ρ = -0.30 to ρ = -0.46; all P < 0.0001). With the use of multiple linear regression, plasma PLP, RBC folate, homocysteine, and cysteine were identified as independent predictors of CRP; and PLP, vitamin B-12, RBC folate, and homocysteine were identified as predictors of SAA. When stratified by folic acid fortification period, nutrition-homocysteine correlations were generally weaker in the postfortification period, whereas associations between plasma PLP and serum CRP increased. Biomarkers of inflammation are associated with PLP, RBC folate, and homocysteine in women. The connection between the pathways needs to be further investigated and causality established. The trial is registered at clinicaltrials.gov as NCT00000611. [ABSTRACT FROM AUTHOR]

Chemoprevention trials have shown that celecoxib reduces adenoma recurrence but can cause cardiovascular toxicity. In this pilot study, we evaluated associations between genetic variation in several candidate pathways (e.g. prostaglandin synthesis) and adenoma recurrence and cardiovascular and gastrointestinal toxicities.Genotyping analysis was carried out on 117 Israeli colorectal adenoma patients who participated in the Prevention of Colorectal Sporadic Adenomatous Polyps trial. Reassessment followed after 3 years on celecoxib and after 2 years from termination of treatment with celecoxib. Efficacy (absence of colorectal adenomas) was measured by colonoscopy at years 1, 3, and 5. Toxicities were assessed by investigators during celecoxib treatment and by self-report post-treatment. A linkage disequilibrium-based selection algorithm (r2≥0.90, MAF≥4%) identified 255 tagSNPs in 25 analyzed candidate genes. Genotyping was performed by using Illumina GoldenGate technology.Multiple genetic variants were associated with adenoma recurrence and toxicity. Genetic variability in COX1, COX2, and ALOX12/15 genes played a role in adenoma recurrence, particularly among patients on placebo. More gene variants (especially variants in PGES, CRP, SRC, and GPX3) were associated with increased risk for cardiovascular toxicity and symptoms, compared with gastrointestinal toxicity and symptoms. The increased risk for cardiovascular toxicity/symptoms associated with the SRC gene variants (rs6017996, rs6018256, rs6018257) ranged from 6.61 (95% confidence interval 1.66-26.36, P<0.01) to 10.71 (95% confidence interval 1.96-58.60, P<0.01).Genetic polymorphisms in multiple inflammation-related genes appear to interact with celecoxib on adenoma recurrence and its attendant toxicity, particularly cardiovascular toxicity/symptoms. Larger studies validating these pharmacogenetic relationships are needed. [ABSTRACT FROM AUTHOR]

A subset of aggressive colorectal cancers exhibit BRAF mutation, MLH1 methylation, and a CpG island methylator phenotype (CIMP), but precursors are poorly established. In this study, we determined the status of these markers in colorectal polyps and evaluated associated risk factors. The study included 771 polyp cases and 1,027 controls who were ages 24 to 80 years, part of a group health program, received a colonoscopy from 1998 to 2007, and completed a structured questionnaire assessing risk factors. Following standard pathology review, polyps were assayed for BRAF mutation (V600E) and tested for and MLH1 and CIMP logistic regression was used to estimate ORs and 95% confidence intervals for the association between molecularly defined subsets of polyps and potential riskfactors. There were 580 conventional adenomas and 419 serrated lesions successfully assayed. For adenomas, the prevalence of each marker was ≤1%. In contrast, 55% of serrated lesions harbored mutant, 26% were CIMP-high, and 5% had methylated MLH1. In these lesions, the highest prevalence of markers was in sessile-serrated polyps (SSP) of ≥10 mm that were in the right-side/cecal regions of the colon. Risk factors for CIMP-high--serrated lesions included Caucasian race, current smoking status, and a history of polyps, whereas for serrated lesions with mutant BRAF, the significant risk factors were male sex, current smoking status, obesity, and a history of polyps. Our results suggest that SSPs and other large, right-sided serrated lesions have a unique molecular profile that is similar to CIMP-high, BRAF-mutated colorectal cancers. [ABSTRACT FROM AUTHOR]

Loss of estrogen receptor β (ERβ) expression in the gut is associated with colorectal cancer (CRC) initiation and progression. Germline single-nucleotide polymorphisms (SNP) in genes for the sex-steroid hormone receptors are not strongly associated with CRC risk; however, these SNPs have not previously been evaluated in relation to survival after diagnosis. We enrolled 729 women, ages 50 to 74, diagnosed with invasive CRC between 1997 and 2002 in 13 counties covered by the Seattle-Puget Sound Surveillance Epidemiology and End Results cancer registry. Participants provided germline DNA. We selected 99 tag-SNPs for the androgen receptor (AR), ERα (ESR1), ERβ (ESR2), and progesterone receptor (PGR) genes. Mortality outcomes were ascertained from the National Death Index. During a median of 6.6 years of follow-up, 244 deaths occurred (161 from CRC). We identified 20 SNPs (12 of ESR2 and 8 of PGR) for replication in 1,729 women diagnosed with incident invasive CRC (555 deaths; 405 from CRC) from three prospective cohort studies that participate in the Genetics and Epidemiology of Colorectal Cancer Consortium. Three correlated SNPs in the promoter of ESR2 (rs2987983, rs3020443, and rs2978381) were statistically significant predictors of CRC-specific and overall survival. Minor alleles of each were associated with improved survival [for rs2987983, CRC-specific HR, 0.77; 95% confidence interval (CI), 0.60-0.99 in the initial study, and HR, 0.79; CI, 0.64-0.98 in replication]. No associations were noted for SNPs of AR, ESR1, or PGR. SNPs in the promoter of may be important to pathways related to the association between ERβ and tumor progression and ESR2 metastasis. [ABSTRACT FROM AUTHOR]

The NFκB-signaling pathway regulates cell proliferation and inflammation. Activation of the pathway is implicated in the etiology of colorectal cancer (CRC). NSAIDs may reduce CRC risk partially through a nuclear factor-kappa B (NFκB)-dependent pathway. In this study, we investigated associations between 34 NFκB1 and 8 IκBKβ tagSNPs and CRC risk and examined interactions with non-steroidal anti-inflammatory drug (NSAID) use. Using conditional logistic regression, we investigated these associations among 1584 incident CRC cases and 2516 sibling controls from the Colon Cancer Family Registry. Three IκBKβ SNPs were associated with a statistically significant lower colorectal or colon cancer risk: rs9694958 (A>G intron 5) (colorectal: ORhzv = 0.26(0.07–0.99), Ptrend = 0.048, Padj = 0.25), rs10958713 (A>C intron 19) (colon: ORhzv = 0.62(0.42–0.92), Ptrend = 0.005, Padj = 0.03) and rs5029748 (C>A intron 2) (colon: ORhet = 0.72(0.56–0.91), Ptrend = 0.01, Padj = 0.08). We replicated trends associated with NFκB1 and IκBKβ variants identified in a previous study (rs4648110 (T>A intron 22), rs13117745 (G>A intron 5) and rs3747811 (T>A intron 1)). IκBKβ’s rs6474387 (C>T intron 20) and rs11986055 (A>C intron 2) showed substantially lower colon cancer risk among current NSAID users (Pinteraction = 0.01 and Pinteraction = 0.045, respectively), whereas NFκB1’s rs230490 (G>A 5ʹ (outside UTR)) and rs997476 (C>A 3ʹ (outside UTR)) showed higher CRC risk among current NSAID users (Pinteraction = 0.01 and Pinteraction = 0.03, respectively). These findings suggest that variants in NFκB1 and IκBKβ are associated with CRC risk and NSAIDs may function partially through an NFκB-dependent pathway. The SNPs identified here should be considered for future functional studies and may be useful in designing a pharmacogenetic approach to preventive NSAID use. [ABSTRACT FROM PUBLISHER]

Abstract: Adipose tissue inflammation is a major mechanistic link between obesity and chronic disease. To isolate and characterize specific leukocyte populations, e.g. by flow cytometry, tissue needs to be processed to digest the extracellular matrix. We have systematically compared the impact of different commonly used collagenase preparations, digestion times, and normalization strategies on the reproducibility of flow cytometric phenotyping of adipose tissue leukocyte populations. Subcutaneous adipose tissue was obtained from 11 anonymous donors undergoing elective procedures at a plastic surgery clinic in Seattle, WA. We found that collagenase alone consistently produced better cell yields (p =0.007) than when combined with additional proteases such as the commercially available liberases. Moreover, liberase significantly degraded the cell surface expression of CD4 (p <0.001) on T cells and to a lesser extent CD16 (p =0.058) on neutrophils. Extension of the digestion interval from 30 to 120min did not significantly impact cell viability (p =0.319) or yield (p =0.247). Normalization by either ‘live-gate’ or percentage of CD45pos leukocytes exhibited the lowest coefficient of variation for tissue digests between 60 and 75min, compared to normalization per gram of tissue, which consistently exhibited the greatest variability. Our data suggest that digestion of adipose tissue using pure collagenase for 60–75min provides the best cell yield and viability, with minimal degradation of cell surface markers used to identify immune cell subpopulations, and best reproducibility independent of the normalization strategy. [Copyright &y& Elsevier]

Abstract: Glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGT) and sulfation, catalyzed by sulfotransferases (SULT), are pathways through which sex steroids are metabolized to less active compounds. These enzymes are highly polymorphic and genetic variants frequently result in higher or lower activity. The phenotypic effects of these polymorphisms on circulating sex steroids in premenopausal women have not yet been investigated. One hundred and seventy women aged 40–45 years had a blood sample drawn during the follicular phase of the menstrual cycle for sex steroid measures and to obtain genomic DNA. Urine was collected for 2-hydroxy (OH) estrone (E1) and 16α-OH E1 measures. Generalized linear regression models were used to assess associations between sex steroids and polymorphisms in the UGT1A and UGT2B families, SULT1A1, and SULT1E1. Women with the UGT1A1(TA7/TA7) genotype had 25% lower mean estradiol (E2) concentrations compared to the wildtype (TA6/TA6) (p =0.02). Similar associations were observed between SULT1A1(R213/H213) and E1 (13% lower mean E1 concentration vs. wildtype; p-value=0.02) and UGT2B4(E458/E458) and dehydroepiandrosterone (DHEA) (20% lower mean DHEA vs. wildtype; p-value=0.03). The SULT1E1(A/C) and the UGT1A1(TA7)–UGT1A3(R11) haplotypes were associated with reduced estrogen concentrations. Further study of UGT and SULT polymorphisms and circulating sex steroid measures in larger populations of premenopausal women is warranted. [Copyright &y& Elsevier]

Background: Genome-wide association studies and subsequent replication studies have shown that single nucleotide polymorphisms (SNPs) in the chromosomal region 8q24 are associated with colorectal cancer susceptibility. Methods: We examined 11 SNP markers in the 8q24 region between 128.47 and 128.54 Mb, using a total of 1,987 colon cases and 2,339 controls who self-reported as white from two independent, well-characterized study populations. Analysis was performed separately within each study, and combined using random effects meta-analysis. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) and to test for effect modification by known colon cancer risk factors. We also performed a meta-analysis combining our results with previous studies. Results: We observed evidence of association for four SNPs in low to high linkage disequilibrium (r² ranging from 0.18 to 0.93) localized in a 16.2 kb region defined by rs10505477 and rs1056368. The combined results for our two studies of colon cancer showed an OR of 1.10 (95% CI: 1.01-1.20, Ptrend = 0.023), and a meta-analysis of our results with previously reported studies of colon and colorectal cancer strongly support the association for this SNP (combined OR for rs6983267 = 1.21, 95% CI: 1.18-1.24, p = 5.5 × 10-44). We did not observe any notable evidence of effect modification by known colon cancer risk factors, and risk did not differ significantly by tumor site or stage. Conclusions: Our study confirms the association between polymorphisms on chromosome 8q24 and colon cancer risk and suggests that the susceptibility locus in region 8q24 is not strongly modified by various lifestyle, environmental, and demographic risk factors for colon cancer. [ABSTRACT FROM AUTHOR]

Abstract: Inflammatory processes, including, specifically, the inflammatory conditions Crohn''s disease (CD) and ulcerative colitis (UC) predispose to colorectal cancer. Interleukin-23 is involved in pro-inflammatory signaling; genetic variation in the interleukin-23 receptor (IL23R) has been consistently associated with CD and UC risk. In three case–control studies of colorectal adenoma (n =485 cases/578 controls), colon cancer (n =1424 cases/1780 controls) and rectal cancer (n =583 cases/775 controls), we investigated associations with 18 candidate and tagSNPs in IL23R. The three studies used an identical Illumina GoldenGate assay, allowing thorough investigation across stages and locations of colorectal neoplasia. We further explored associations with molecular cancer subtypes (MSI+, CIMP+, KRAS2mut, TP53mut). In this comprehensive study of genetic variability in IL23R across the spectrum of colorectal carcinogenesis, as well as within colon and rectal tumor molecular subtypes, we observed associations between SNPs in IL23R and risk of rectal cancer: the 88413 C>A (rs10889675) and 69450 C>A (rs7542081) polymorphisms were associated with decreased rectal cancer risk overall (p-trend=0.04 and 0.05 respectively), and specifically with rectal tumors bearing a TP53 mutation (88413 CA/AA vs. CC OR: 0.66; 95% CI: 0.46–94; 69450 CA/AA vs. CC OR: 0.60; 95% CI: 0.37–0.98). However, none of associations remained statistically significant after correction for multiple testing. These data provide some evidence that genetic variability in IL23R may contribute to rectal cancer risk and should be evaluated in additional studies. [Copyright &y& Elsevier]