bluuebunny/crossref_metadata_2025 huggingface dataset:
Rare mutations in the human Na-K-Cl cotransporter (NKCC2) associated with lower blood pressure exhibit impaired processing and transport function
Authors: Monette Michelle Y. , Rinehart Jesse , Lifton Richard P. , Forbush Biff
Published: January 2011

The Na-K-Cl cotransporter (NKCC2) is the major salt transport pathway in the thick ascending limb of Henle's loop and is part of the molecular mechanism for blood pressure regulation. Recent screening of ∼3,000 members of the Framingham Heart Study identified nine rare independent mutations in the gene encoding NKCC2 (SLC12A1) associated with clinically reduced blood pressure and protection from hypertension (Ji WZ, Foo JN, O'Roak BJ, Zhao H, Larson MG, Simon DB, Newton-Cheh C, State M, Levy D, Lifton RP. Nat Genet 40: 592–599, 2008). To investigate their functional consequences, we introduced the nine mutations in human NKCC2A and examined protein function, expression, localization, regulation, and ion transport kinetics using heterologous expression in Xenopus laevis oocytes and HEK-293 cells. When expressed in oocytes, four of the mutants (T235M, R302W, L505V, and P569H) exhibited reduced transport function compared with wild-type. In HEK-293 cells, the same four mutants exhibited reduced function, and in addition N399S and P1083A had significantly lower activity than wild-type. The two most functionally impaired mutants (R302W and L505V) exhibited dramatically diminished production of complex-glycosylated protein and a decrease in or absence of plasma membrane localization, indicative of a processing defect. All of the functional human (h) NKCC2A variants were regulated by changes in oocyte volume and intracellular chloride in HEK cells, but P254A and N399S exhibited a lower constitutive activity in HEK cells. The P569H mutant exhibited a 50% reduction in sodium affinity compared with wild-type, predicting lower transport activity at lower intratubular salt concentrations, while the P254A mutant exhibited a 35% increase in rubidium affinity. We conclude that defects in NKCC2 processing, transport turnover rate, regulation, and ion affinity contribute to impaired transport function in six of the nine identified mutants, providing support for the predictive approach of Ji et al. to identify functionally important residues by sequence conservation. Such mutations in hNKCC2A are likely to reduce renal salt reabsorption, providing a mechanism for lower blood pressure.
Reciprocal expression of connexin 40 and 45 during phenotypical changes in renin-secreting cells
Authors: Kurt Birguel , Kurtz Lisa , Sequeira-Lopez Maria L. , Gomez R. Ariel , Willecke Klaus , Wagner Charlotte , Kurtz Armin
Published: January 2011

Gap junctional coupling of renin-producing cells is of major functional importance for the control of renin synthesis and release. This study was designed to determine the relevance of the vascular gap junction protein connexin 45 (Cx45) for the control of renin expression and secretion. By crossbreeding mice which drive Cre recombinase under the control of the endogenous renin promoter with mice harboring floxed Cx45 gene alleles, we generated viable mice with a deletion of Cx45 in the renin cell lineage. These mice were normotensive, and renin cells in their kidneys were normal with regard to localization and number. Sodium deficiency induced typical recruitment of renin-producing cells along afferent arterioles, whereas sodium overload resulted in a decrease in the number of cells expressing renin. Regulation of renin secretion by perfusion pressure, catecholamines, and angiotensin II from isolated kidneys of mice with renin cell-specific deletion of Cx45 was normal. Analyzing Cx45 promoter activity in cells of the preglomerular arteriolar tree by using mice driving the reporter gene LacZ under the control of the Cx45 promoter revealed strong staining in smooth muscle cells of the media, whereas renin-expressing cells were almost devoid of LacZ staining. Conversely, renin-producing cells, but not vascular smooth muscle cells expressed the gap junction protein Cx40. These findings suggest that Cx45 plays no major functional role in renin-producing cells, probably because the expression of Cx45 is downregulated in these cells. Since renin-producing cells in the adult kidney can reversibly transform into vascular smooth muscle cells and vice versa, our findings on connexin expression indicate that these phenotype switches are paralleled by characteristic reciprocal changes in the transcriptional activity of Cx40 and Cx45 genes.
Chronic alcohol exposure negatively impacts the physiological and molecular parameters of the renal biotin reabsorption process
Authors: Subramanian Veedamali S. , Subramanya Sandeep B. , Said Hamid M.
Published: January 2011

Normal body homeostasis of biotin is critically dependent on its renal recovery by kidney proximal tubular epithelial cells, a process that is mediated by the sodium-dependent multivitamin transporter (SMVT; a product of the SLC5A6 gene). Chronic ethanol consumption interferes with the renal reabsorption process of a variety of nutrients, including water-soluble vitamins. To date, however, there is nothing known about the effect of chronic alcohol feeding on physiological and molecular parameters of the renal biotin reabsorption process. We addressed these issues using rats and transgenic mice carrying the human SLC5A6 (P1P2) 5′-regulatory region as an in vivo model systems of alcohol exposure, and cultured human renal proximal tubular epithelial HK-2 cells chronically exposed to alcohol as an in vitro model of alcohol exposure. The [3H]biotin uptake results showed that chronic ethanol feeding in rats leads to a significant inhibition in carrier-mediated biotin transport across both renal brush border and basolateral membrane domains. This inhibition was associated with a marked reduction in the level of expression of SMVT protein, mRNA, and heterogenous nuclear RNA (hnRNA). Furthermore, studies with transgenic mice carrying the SLC5A6 5′-regulatory region showed that chronic alcohol feeding leads to a significant decrease in promoter activity. Studies with HK-2 cells chronically exposed to alcohol again showed a marked reduction in carrier-mediated biotin uptake, which was associated with a significant reduction in promoter activity of the human SLC5A6 5′-regulatory region. These findings demonstrate for the first time that chronic ethanol feeding inhibits renal biotin transport and that this effect is, at least in part, being exerted at the transcriptional level.
Dystroglycan does not contribute significantly to kidney development or function, in health or after injury
Authors: Jarad George , Pippin Jeffrey W. , Shankland Stuart J. , Kreidberg Jordan A. , Miner Jeffrey H.
Published: January 2011

Dystroglycan (DG or DAG1) is considered a critical link between the basement membrane and the cytoskeleton in multiple tissues. DG consists of two subunits, an extracellular α-subunit that binds laminin and other basement membrane components, and a transmembrane β-subunit. DG-null mouse embryos die during early embryogenesis because DG is required for Reichert's membrane formation. DG also forms an integral part of the dystrophin-glycoprotein complex in muscle. Although no human DG mutations have been reported, multiple forms of muscular dystrophy have been linked to DG glycosylation defects, and targeted deletion of muscle DG causes muscular dystrophy in mice. Moreover, DG is widely distributed in endothelial and epithelial cells, including those in the kidney. There has therefore been significant interest in DG's role in the kidney, especially in podocytes. Previous reports suggested that DG's disturbance in podocytes might cause glomerular filtration barrier abnormalities. To fully understand DG's contribution to nephrogenesis and kidney function, we used a conditional DG allele and a variety of Cre mice to systematically delete DG from podocytes, ureteric bud, metanephric mesenchyme, and then from the whole kidney. Surprisingly, none of these conditional deletions resulted in significant morphological or functional abnormalities in the kidney. Furthermore, DG-deficient podocytes did not show increased susceptibility to injury, and DG-deficient kidneys did not show delayed recovery. Integrins are therefore likely the primary extracellular matrix receptors in renal epithelia.
Moderate weight loss improves heart rate variability in overweight and obese adults with type 2 diabetes
Authors: Sjoberg Nicholas , Brinkworth Grant D. , Wycherley Thomas P. , Noakes Manny , Saint David A.
Published: January 2011

The objective of this study was to determine the effects of weight loss on heart rate variability (HRV) and its association with traditional cardiovascular disease risk factors in overweight and obese patients with type 2 diabetes. Forty five patients [body mass index (BMI) 35.4 ± 0.7 kg/m2; age 56.5 ± 1.1 yr] with type 2 diabetes followed an energy-restricted diet (6–7 MJ/day) for 16 wk. Body weight, blood pressure, glucose, insulin, insulin resistance [homeostasis model assessment index 2 (HOMA2)], glycosylated hemoglobin (HbA1c), total cholesterol, low-density lipoproteins (LDL), high-density lipoproteins (HDL), triglycerides, resting HR, and HRV were measured before and after the intervention period. Mean reduction in body weight was 11.1 ± 1.0 kg (10%), with significant reductions in blood pressure (−10%), total cholesterol (−15.9%), LDL (−17.7%), HDL (−7.5%), triglycerides (−21.2%), glucose (−23.4%), insulin (−37.6%), HOMA2 (−40.1%), and HbA1c (−14.5%) ( P ≤ 0.05 for all variables). There were increases in several HRV components, including total power (1,370 ± 280 to 2,045 ± 280 ms2), low-frequency power (345 ± 70 to 600 ± 108 ms2), SD of normal to normal intervals (SDNN; 35.0 ± 2.5 to 43.0 ± 2.7 s), and square root of the mean squared differences of successive normal to normal intervals (RMSSD; 23.0 ± 3.5 to 32.0 ± 3.1 s), and a decrease in HR (69.0 ± 1.3 to 60.0 ± 1.2 beats/min) ( P ≤ 0.03 for all variables). Changes in HR, SDNN, total power, and low-frequency power correlated with change in BMI ( P < 0.05). In addition to improvements in traditional cardiovascular and metabolic risk factors, weight loss improves HRV in overweight and obese patients with type 2 diabetes.
Distance- and activity-dependent modulation of spike back-propagation in layer V pyramidal neurons of the medial entorhinal cortex
Authors: Gasparini Sonia
Published: January 2011

Layer V principal neurons of the medial entorhinal cortex receive the main hippocampal output and relay processed information to the neocortex. Despite the fundamental role hypothesized for these neurons in memory replay and consolidation, their dendritic features are largely unknown. High-speed confocal and two-photon Ca2+ imaging coupled with somatic whole cell patch-clamp recordings were used to investigate spike back-propagation in these neurons. The Ca2+ transient associated with a single back-propagating action potential was considerably smaller at distal dendritic locations (>200 μm from the soma) compared with proximal ones. Perfusion of Ba2+ (150 μM) or 4-aminopyridine (2 mM) to block A-type K+ currents significantly increased the amplitude of the distal, but not proximal, Ca2+ transients, which is strong evidence for an increased density of these channels at distal dendritic locations. In addition, the Ca2+ transients decreased with each subsequent spike in a 20-Hz train; this activity-dependent decrease was also more prominent at more distal locations and was attenuated by the perfusion of the protein kinase C activator phorbol-di-acetate. These data are consistent with a phosphorylation-dependent control of back-propagation during trains of action potentials, attributable mainly to an increase in the time constant of recovery from voltage-dependent inactivation of dendritic Na+ channels. In summary, dendritic Na+ and A-type K+ channels control spike back-propagation in layer V entorhinal neurons. Because the activity of these channels is highly modulated, the extent of the dendritic Ca2+ influx is as well, with important functional implications for dendritic integration and associative synaptic plasticity.
Internal curvature signal and noise in low- and high-level vision
Authors: Sweeny Timothy D. , Grabowecky Marcia , Kim Yee Joon , Suzuki Satoru
Published: January 2011

How does internal processing contribute to visual pattern perception? By modeling visual search performance, we estimated internal signal and noise relevant to perception of curvature, a basic feature important for encoding of three-dimensional surfaces and objects. We used isolated, sparse, crowded, and face contexts to determine how internal curvature signal and noise depended on image crowding, lateral feature interactions, and level of pattern processing. Observers reported the curvature of a briefly flashed segment, which was presented alone (without lateral interaction) or among multiple straight segments (with lateral interaction). Each segment was presented with no context (engaging low-to-intermediate-level curvature processing), embedded within a face context as the mouth (engaging high-level face processing), or embedded within an inverted-scrambled-face context as a control for crowding. Using a simple, biologically plausible model of curvature perception, we estimated internal curvature signal and noise as the mean and standard deviation, respectively, of the Gaussian-distributed population activity of local curvature-tuned channels that best simulated behavioral curvature responses. Internal noise was increased by crowding but not by face context (irrespective of lateral interactions), suggesting prevention of noise accumulation in high-level pattern processing. In contrast, internal curvature signal was unaffected by crowding but modulated by lateral interactions. Lateral interactions (with straight segments) increased curvature signal when no contextual elements were added, but equivalent interactions reduced curvature signal when each segment was presented within a face. These opposing effects of lateral interactions are consistent with the phenomena of local-feature contrast in low-level processing and global-feature averaging in high-level processing.
Elevated potassium elicits recurrent surges of large GABAA-receptor-mediated post-synaptic currents in hippocampal CA3 pyramidal neurons
Authors: Shin Damian Seung-Ho , Yu Wilson , Sutton Alex , Calos Megan , Carlen Peter Louis
Published: January 2011

Previously, we found that rat hippocampal CA3 interneurons become hyperactive with increasing concentrations of extracellular K+up to 10 mM. However, it is unclear how this enhanced interneuronal activity affects pyramidal neurons. Here we voltage-clamped rat hippocampal CA3 pyramidal neurons in vitro at 0 mV to isolate γ-aminobutyric acid (GABA)-activated inhibitory post-synaptic currents (IPSCs) and measured these in artificial cerebrospinal fluid (aCSF) and with 10 mM K+bath perfusion. In aCSF, small IPSCs were present with amplitudes of 0.053 ± 0.007 nA and a frequency of 0.27 ± 0.14 Hz. With 10 mM K+perfusion, IPSCs increased greatly in frequency and amplitude, culminating in surge events with peak amplitudes of 0.56 ± 0.08 nA, that appeared and disappeared cyclically with durations lasting 2.02 ± 0.37 min repeatedly, up to 10 times over a 30-min bath perfusion of elevated K+. These large IPSCs were GABAA-receptor mediated and did not involve significant desensitization of this receptor. Perfusion of a GABA transporter inhibitor (NO-711), glutamate receptor inhibitors CNQX and APV, or a gap junctional blocker (carbenoxolone) prevented the resurgence of large IPSCs. Pressure ejected sucrose resulted in the abolishment of subsequent surges. No elevated K+-mediated surges were observed in CA3 interneurons from the stratum oriens layer. In conclusion, these cyclic large IPSC events observable in CA3 pyramidal neurons in 10 mM KCl may be due to transient GABA depletion from continuously active interneuronal afferents.
Inhibition of SK and M channel-mediated currents by 5-HT enables parallel processing by bursts and isolated spikes
Authors: Deemyad Tara , Maler Leonard , Chacron Maurice J.
Published: January 2011

Although serotonergic innervation of sensory brain areas is ubiquitous, its effects on sensory information processing remain poorly understood. We investigated these effects in pyramidal neurons within the electrosensory lateral line lobe (ELL) of weakly electric fish. Surprisingly, we found that 5-HT is present at different levels across the different ELL maps; the presence of 5-HT fibers was highest in the map that processes intraspecies communication signals. Electrophysiological recordings revealed that 5-HT increased excitability and burst firing through a decreased medium afterhyperpolarization resulting from reduced small-conductance calcium-activated (SK) currents as well as currents mediated by an M-type potassium channel. We next investigated how 5-HT alters responses to sensory input. 5-HT application decreased the rheobase current, increased the gain, and decreased first spike latency. Moreover, it reduced discriminability between different stimuli, as quantified by the mutual information rate. We hypothesized that 5-HT shifts pyramidal neurons into a burst-firing mode where bursts, when considered as events, can detect the presence of particular stimulus features. We verified this hypothesis using signal detection theory. Our results indeed show that serotonin-induced bursts of action potentials, when considered as events, could detect specific stimulus features that were distinct from those detected by isolated spikes. Moreover, we show the novel result that isolated spikes transmit more information after 5-HT application. Our results suggest a novel function for 5-HT in that it enables differential processing by action potential patterns in response to current injection.
Genome-Based Prediction of Breast Cancer Risk in the General Population: A Modeling Study Based on Meta-Analyses of Genetic Associations
Authors: van Zitteren Moniek , van der Net Jeroen B. , Kundu Suman , Freedman Andrew N. , van Duijn Cornelia M. , Janssens A. Cecile J.W.
Published: January 2011

Background: Genome-wide association studies identified novel breast cancer susceptibility variants that could be used to predict breast cancer in asymptomatic women. This review and modeling study aimed to investigate the current and potential predictive performance of genetic risk models.

Methods: Genotypes and disease status were simulated for a population of 10,000 women. Genetic risk models were constructed from polymorphisms from meta-analysis including, in separate scenarios, all polymorphisms or statistically significant polymorphisms only. We additionally investigated the magnitude of the odds ratios (OR) for 1 to 100 hypothetical polymorphisms that would be needed to achieve similar discriminative accuracy as available prediction models [modeled range of area under the receiver operating characteristic curve (AUC) 0.70–0.80].

Results: Of the 96 polymorphisms that had been investigated in meta-analyses, 41 showed significant associations. AUC was 0.68 for the genetic risk model based on all 96 polymorphisms and 0.67 for the 41 significant polymorphisms. Addition of 50 additional variants, each with risk allele frequencies of 0.30, requires per-allele ORs of 1.2 to increase this AUC to 0.70, 1.3 to increase AUC to 0.75, and 1.5 to increase AUC to 0.80. To achieve AUC of 0.80, even 100 additional variants would need per-allele ORs of 1.3 to 1.7, depending on risk allele frequencies.

Conclusion: The predictive ability of genetic risk models in breast cancer has the potential to become comparable to that of current breast cancer risk models.

Impact: Risk prediction based on low susceptibility variants becomes a realistic tool in prevention of nonfamilial breast cancer. Cancer Epidemiol Biomarkers Prev; 20(1); 9–22. ©2011 AACR.
Effect of Oral Snus and Medicinal Nicotine in Smokers on Toxicant Exposure and Withdrawal Symptoms: A Feasibility Study
Authors: Kotlyar Michael , Hertsgaard Louise A. , Lindgren Bruce R. , Jensen Joni A. , Carmella Steven G. , Stepanov Irina , Murphy Sharon E. , Hecht Stephen S. , Hatsukami Dorothy K.
Published: January 2011

Background: Smokeless, spitless tobacco products are being introduced and marketed as cigarette substitutes. Data are needed regarding how smokers interested in cessation would use these products, the levels of resultant toxicant exposure, and the feasibility of using these products as aids for tobacco cessation.

Methods: Smokers were randomized to receive Camel Snus (n = 51), Taboka (n = 52), or medicinal nicotine (n = 27) and required to quit smoking for 4 weeks. Measures of toxicant exposure and symptoms of craving and withdrawal were assessed prior to and during product use.

Results: Concentrations of exhaled carbon monoxide, urinary cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and urinary N′-nitrosonornicotine and its glucuronide (total NNN) were significantly (P values <0.05) lower at the end of treatment in each group except for total NNN in those receiving Camel Snus (P = 0.066). A significant group × time effect was observed for total NNAL concentrations (P = 0.002) with the decrease greatest in the medicinal nicotine group and smallest decrease in the Camel Snus group. No significant differences between groups were found in craving and withdrawal symptoms.

Conclusions: Enrolling smokers into a cessation study utilizing newer smokeless tobacco products is feasible. Camel Snus and Taboka use was not found to be superior to medicinal nicotine in reducing withdrawal symptoms but decreases in NNAL were smaller in users of Camel Snus.

Impact: This study demonstrates the feasibility of conducting a smoking cessation study utilizing these newer tobacco products. An appropriately powered study is needed to assess smoking cessation rates using these newer products compared with established, safer products such as medicinal nicotine. Cancer Epidemiol Biomarkers Prev; 20(1); 91–100. ©2011 AACR.
Reduced Plasma Level of CXC Chemokine Ligand 7 in Patients with Pancreatic Cancer
Authors: Matsubara Junichi , Honda Kazufumi , Ono Masaya , Tanaka Yoshinori , Kobayashi Michimoto , Jung Giman , Yanagisawa Koji , Sakuma Tomohiro , Nakamori Shoji , Sata Naohiro , Nagai Hideo , Ioka Tatsuya , Okusaka Takuji , Kosuge Tomoo , Tsuchida Akihiko , Shimahara Masashi , Yasunami Yohichi , Chiba Tsutomu , Hirohashi Setsuo , Yamada Tesshi
Published: January 2011

Background: Early detection is essential to improve the outcome of patients with pancreatic cancer. A noninvasive and cost-effective diagnostic test using plasma/serum biomarkers would facilitate the detection of pancreatic cancer at the early stage.

Methods: Using a novel combination of hollow fiber membrane–based low-molecular-weight protein enrichment and LC-MS-based quantitative shotgun proteomics, we compared the plasma proteome between 24 patients with pancreatic cancer and 21 healthy controls (training cohort). An identified biomarker candidate was then subjected to a large blinded independent validation (n = 237, validation cohort) using a high-density reverse-phase protein microarray.

Results: Among a total of 53,009 MS peaks, we identified a peptide derived from CXC chemokine ligand 7 (CXCL7) that was significantly reduced in pancreatic cancer patients, showing an area under curve (AUC) value of 0.84 and a P value of 0.00005 (Mann–Whitney U test). Reduction of the CXCL7 protein was consistently observed in pancreatic cancer patients including those with stage I and II disease in the validation cohort (P < 0.0001). The plasma level of CXCL7 was independent from that of CA19-9 (Pearson's r = 0.289), and combination with CXCL7 significantly improved the AUC value of CA19-9 to 0.961 (P = 0.002).

Conclusions: We identified a significant decrease of the plasma CXCL7 level in patients with pancreatic cancer, and combination of CA19-9 with CXCL7 improved the discriminatory power of the former for pancreatic cancer.

Impact: The present findings may provide a new diagnostic option for pancreatic cancer and facilitate early detection of the disease. Cancer Epidemiol Biomarkers Prev; 20(1); 160–71. ©2011 AACR.
Variations in Chromosomes 9 and 6p21.3 with Risk of Non–Hodgkin Lymphoma
Authors: Wang Sophia S. , Menashe Idan , Cerhan James R. , Cozen Wendy , Severson Richard K. , Davis Scott , Hutchinson Amy , Rothman Nathaniel , Chanock Stephen J. , Bernstein Leslie , Hartge Patricia , Morton Lindsay M.
Published: January 2011

Background: There is growing evidence linking genetic variations to non–Hodgkin lymphoma (NHL) etiology. To complement ongoing agnostic approaches for identifying susceptibility genes, we evaluated 488 candidate gene regions and their relation to risk for NHL and NHL subtypes.

Methods: We genotyped 6,679 tag single nucleotide polymorphisms (SNPs) in 947 cases and 826 population-based controls from a multicenter U.S. case–control study. Gene-level summary of associations were obtained by computing the minimum P value (“minP test”) on the basis of 10,000 permutations. We used logistic regression to evaluate the association between genotypes and haplotypes with NHL. For NHL subtypes, we conducted polytomous multivariate unconditional logistic regression (adjusted for sex, race, age). We calculated P-trends under the codominant model for each SNP.

Results: Fourteen gene regions were associated with NHL (P < 0.01). The most significant SNP associated with NHL maps to the SYK gene (rs2991216, P-trend = 0.00005). The three most significant gene regions were on chromosome 6p21.3 (RING1/RXRB; AIF1; BAT4). Accordingly, SNPs in RING1/RXRB (rs2855429), AIF1 (rs2857597), and BAT4 (rs3115667) were associated with NHL (P-trends ≤ 0.0002) and both diffuse large B-cell and follicular lymphomas (P-trends < 0.05).

Conclusions: Our results suggest potential importance for SYK on chromosome 9 with NHL etiology. Our results further implicate 6p21.3 gene variants, supporting the need for full characterization of this chromosomal region in relation to lymphomagenesis.

Impact: Gene variants on chromosome 9 may represent a new region of interesting for NHL etiology. The independence of the reported variants in 6p21.3 from implicated variants (TNF/HLA) supports the need to confirm causal variants in this region Cancer Epidemiol Biomarkers Prev; 20(1); 42–9. ©2011 AACR.
The Epidemiology of Oral HPV Infection among a Multinational Sample of Healthy Men
Authors: Kreimer Aimee R. , Villa Alessandro , Nyitray Alan G. , Abrahamsen Martha , Papenfuss Mary , Smith Danelle , Hildesheim Allan , Villa Luisa L. , Lazcano-Ponce Eduardo , Giuliano Anna R.
Published: January 2011

Background: Oral human papillomavirus type-16 (HPV16) infection is a risk factor for oropharyngeal cancer. We examined oral HPV infection among healthy men.

Methods: Oral rinse/gargle specimens and questionnaire data were collected from 1,688 healthy men aged 18 to 74 (median = 31 years), from the United States, Mexico, and Brazil. HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59, and noncarcinogenic HPV types were detected using Roche Linear Array.

Results: Oral HPV DNA was detected in 67 of 1,680 (4.0%, 95% CI = 3.1%–5.0%) β-globin–positive specimens; carcinogenic HPVs were detected in 1.3% (95% CI = 0.8%–2.0%; n = 22) and HPV16 was the most commonly detected carcinogenic HPV type (0.6%, 95% CI = 0.2%–1.1%; n = 10). The prevalence of oral HPV infection was similar by country except for HPV55, which had notably higher prevalence in Mexico (3.0%) than Brazil (0%) or the United States (0.2%). Oral HPV prevalence nonsignificantly increased over increasing age categories (Ptrend = 0.096). The strongest predictor of oral HPV was current tobacco use, which increased the odds 2.5-fold (95% CI = 1.4–4.4). Oral sexual behaviors were not associated with oral HPV infection.

Conclusions: Oral HPV16 infection was rare in healthy men, especially at younger ages, and was positively associated with current tobacco use.

Impact: Oral HPV appears to be about 10-fold less prevalent than infection at genital sites in men (4% vs. ∼40%, respectively). It remains unclear whether this reflects reduced exposure or if the oral region is more resistant to HPV infection compared with anogenital sites. Cancer Epidemiol Biomarkers Prev; 20(1); 172–82. ©2011 AACR.
Risk of Cervical Cancer Associated with Allergies and Polymorphisms in Genes in the Chromosome 5 Cytokine Cluster
Authors: Johnson Lisa G. , Schwartz Stephen M. , Malkki Mari , Du Qin , Petersdorf Effie W. , Galloway Denise A. , Madeleine Margaret M.
Published: January 2011

Background: Human papillomavirus is the acknowledged cause of cervical cancer. We hypothesized that allergies, characterized by hyperimmune reaction to common allergens and which have been associated with various cancers, may be related to cervical cancer, and that genetic variation in cytokine genes related to allergies might impact cervical cancer risk.

Methods: We investigated the risk of invasive squamous cell cervical cancer (SCC) associated with self-reported allergies and with variation in allergy-related cytokine genes using data from a case–control study (561 cases, 1,258 controls) conducted in Washington State. Logistic regression models yielded odds ratios (OR) and 95% CI.

Results: Pollen allergy, the most commonly reported allergy, was associated with reduced SCC risk (OR: 0.6; 95% CI: 0.5–0.8). Of 60 tagging single-nucleotide polymorphisms covering eight genes (CSF2, IL3, IL4, IL13, CSF2RB, IL4R, IL13RA1, IL13RA2), several were related to pollen allergies among controls: IL4R rs3024647 (dominant OR: 1.5; 95% CI: 1.0–2.3; P = 0.04), CSF2RB rs16997517 (dominant OR: 2.2; 95% CI: 1.0–4.7; P = 0.04), and IL13 rs1800925 (per-allele OR: 1.7; 95% CI: 1.3–2.4; P = 0.0007). Two variants were inversely associated with SCC risk: IL4R rs3024656 (per-allele OR: 0.8; 95% CI: 0.6–1.0; P = 0.03) and CSF2RB rs16997517 (dominant OR: 0.4; 95% CI: 0.2–0.9; P = 0.04).

Conclusions: Pollen allergies were related to reduced SCC risk. CSF2RB rs16997517 was directly related to pollen allergies in controls and to reduced SCC risk.

Impact: If other studies confirm these results, the mechanism behind allergy-associated immune response associated with SCC risk may be worth exploring in the context of therapeutic or prophylactic vaccines. Cancer Epidemiol Biomarkers Prev; 20(1); 199–207. ©2011 AACR.
Development and Validation of a New, Sensitive Immunochemical Assay for O6-Methylguanine in DNA and Its Application in a Population Study
Authors: Georgiadis Panagiotis , Kaila Stella , Makedonopoulou Paraskevi , Fthenou Eleni , Chatzi Leda , Pletsa Vasiliki , Kyrtopoulos Soterios A.
Published: January 2011

Background: Investigations of the presence of the precarcinogenic DNA adduct O6-methylguanine (O6-meG) in humans and its association with exposure or cancer risk have been hindered by the absence of analytic methods of adequate sensitivity and throughput. We report the development, validation, and application of an ELISA-type assay for O6-meG appropriate for large-scale population studies.

Methods: In the new analytic method, restriction enzymes are used to digest DNA to fragments of size expected to contain no more than one O6-meG residue. Anti-adduct antisera are used to transfer O6-meG–containing fragments to a solid surface, where they are detected using anti-ssDNA antisera, the high ratio of normal nucleotides to adducts providing a strong signal enhancement.

Results: An assay with a limit of detection of 1.5 adducts/109 nucleotides using 10 μg of DNA, a dynamic range of approximately two orders of magnitude and satisfactory precision and accuracy characteristics was established and validated. Analysis of samples from 120 subjects from the Rhea mother–child cohort in Crete led to the detection of O6-meG in 70% of maternal and 50% of cord blood buffy coat samples at mean levels of 0.65 and 0.38 adducts/108 nucleotides, respectively.

Conclusions: The frequent observation of O6-meG in human DNA is compatible with dietary compounds (e.g. N-nitroso compounds or their precursors), or endogenous processes being responsible for the formation of this adduct.

Impact: The new assay opens the way for large-scale population studies of O6-meG as a biomarker of exposure or risk. The approach used in this assay can, in principle, be extended to any DNA adduct for which suitable antisera are available. Cancer Epidemiol Biomarkers Prev; 20(1); 82–90. ©2011 AACR.
Genetic Variation in VEGF Family Genes and Breast Cancer Risk: A Report from the Shanghai Breast Cancer Genetics Study
Authors: Beeghly-Fadiel Alicia , Shu Xiao-Ou , Lu Wei , Long Jirong , Cai Qiuyin , Xiang Yong-Bing , Zheng Ying , Zhao Zhongming , Gu Kai , Gao Yu-Tang , Zheng Wei
Published: January 2011

Background: In addition to mediating aspects of physiologic and pathologic angiogenesis, the VEGF family also contributes to carcinogenesis.

Methods: We comprehensively characterized genetic variation across four VEGF family genes and evaluated associations with breast cancer risk with odds ratios (OR) and 95% CIs for participants of the two-stage case–control Shanghai Breast Cancer Genetics Study (SBCGS). Stage 1 evaluated 200 single nucleotide polymorphisms (SNP) across two VEGF ligands (VEGFA and VEGFC) and two VEGF receptors (FLT1/VEGFR1 and KDR/VEGFR2) among 2,079 cases and 2,148 controls. Five SNPs with promising associations were assessed in stage 2 among 4,419 cases and 1,851 controls.

Results: Two SNPs were consistently associated with breast cancer risk across our two study stages and were significant in combined analyses. Compared with FLT1 rs9551471 major allele homozygotes (AA), reduced risks were associated with AG (OR = 0.92, 95% CI: 0.84–1.00) and GG (OR = 0.78, 95% CI: 0.64–0.95) genotypes (Ptrend = 0.005). Compared with VEGFA rs833070 major allele carriers (CC or CT), increased risk was associated with TT genotypes (OR = 1.26, 95% CI: 1.05–1.52, P = 0.016).

Conclusion: Results from our study indicate that common genetic variation in VEGFA and FLT1 (VEGFR1) may contribute to breast cancer susceptibility.

Impact: Our findings provide clues for future studies on VEGF family genes in relation to cancer susceptibility and survival. Cancer Epidemiol Biomarkers Prev; 20(1); 33–41; ©2011 AACR.
Dating the Rise of Esophageal Adenocarcinoma: Analysis of Connecticut Tumor Registry Data, 1940–2007
Authors: Abrams Julian A. , Sharaiha Reem Z. , Gonsalves Lou , Lightdale Charles J. , Neugut Alfred I.
Published: January 2011

Background: The timing of onset of the rise in incidence of esophageal adenocarcinoma (EAC) has not been clearly defined, and doing so may provide clues with regard to exposures associated with the changed epidemiology of this malignancy. We therefore aimed to investigate historical trends in the incidence of EAC and other upper gastrointestinal malignancies.

Methods: We did a population-based study using Connecticut Tumor Registry (1940–2007) and Surveillance, Epidemiology, and End Results (SEER; 1973–2007) data. Age-adjusted incidence rates (per 100,000 person-years) were calculated for EAC and other upper gastrointestinal malignancies.

Results: The incidence of EAC remained relatively constant until 1965–69, and then rose from 0.41 (95%CI, 0.26–0.56) to 1.31 (95%CI 1.07–1.54) in 1978–82 and 5.31 (95%CI 4.89–5.73) in 2003–07. The incidence of gastric cardia cancer began to rise in the 1950s and plateaued in the 1990s. The incidence of esophageal squamous cell carcinoma began to decrease around 1980. The trends from Connecticut Tumor Registry data closely mirrored those from SEER data.

Conclusions: The incidence of EAC began to rise in the late 1960s, predating the rise in obesity by a decade. Reduced infection rates of Helicobacter pylori, changes in microbiome, or other exposures may have contributed to the changed epidemiology of this malignancy.

Impact: Analysis of historical data of trends in EAC incidence implicate a change in environmental factors from the mid-20th century as primarily responsible for the initial rise in EAC incidence, predating the rise in obesity prevalence in the United States by over a decade. Cancer Epidemiol Biomarkers Prev; 20(1); 183–6. ©2011 AACR.
Metformin and Incident Breast Cancer among Diabetic Women: A Population-Based Case–Control Study in Denmark
Authors: Bosco Jaclyn Lee Fong , Antonsen Sussie , Sørensen Henrik Toft , Pedersen Lars , Lash Timothy L.
Published: January 2011

Background: Preliminary evidence suggests that metformin may decrease breast cancer risk by decreasing insulin levels and reducing cell proliferation. We evaluated the effect of metformin medication on the risk of incident breast cancer among peri- and postmenopausal women.

Methods: We used Danish medical registries to conduct a nested case–control study among type 2 diabetic women 50 years or older who resided in northern Denmark from 1989 to 2008 (n = 4,323). We identified 393 diabetic cases and used risk-set sampling to select 10 diabetic controls per case (n = 3,930) matched on county of residence. Odds ratios (OR) and 95% CIs were estimated by conditional logistic regression associating metformin use with breast cancer occurrence.

Results: Ninety-six cases (24%) and 1,154 controls (29%) used metformin for at least 1-year duration. Cases were slightly older on average than controls, but they were similar in distribution for parity, use of hormone replacement therapy, and history of diabetes complications. Metformin users were less likely with a diagnosis of breast cancer (OR = 0.77; 95% CI = 0.61–0.99) than nonmetformin users. Adjustment for diabetes complications, clinically diagnosed obesity, and important predictors of breast cancer did not substantially alter the association (OR = 0.81; 95% CI = 0.63–0.96).

Conclusion: Our results suggest that metformin may protect against breast cancer in type 2 diabetic peri- or postmenopausal women.

Impact: This study supports the growing evidence of a role for metformin in breast cancer chemoprevention. Cancer Epidemiol Biomarkers Prev; 20(1); 101–11. ©2011 AACR.
Genetic Variation in the TGF-β Signaling Pathway and Colon and Rectal Cancer Risk
Authors: Slattery Martha L. , Herrick Jennifer S. , Lundgreen Abbie , Wolff Roger K.
Published: January 2011

Background: The TGF-β signaling pathway is an essential regulator of many cellular process involved in carcinogenesis. Smad proteins are central to the function of TGF-β signaling. In this study, we evaluated genetic variation in TGFβ1, TGFβR1, Smad1, Smad2, Smad3, and Smad4 and risk of colon and rectal cancer.

Methods: Data are from a large case–control study of colon (n = 1,444 cases, 1,841 controls) and rectal (n = 754 cases, 856 controls) cancer participants with DNA.

Results: Both TGFβ1 rs1800469 and rs4803455 were associated with colon cancer [odds ratio (OR) = 0.65 and 1.43, 95% CI = 0.51–0.84 and 1.18–1.73, respectively) but not rectal cancer. Likewise, 1 of 3 tagSNPs for TGFβR1, 2 of the 4 tagSNPs for Smad2, and 4 of 37 Smad3 tagSNPs were associated with colon cancer. Fewer significant associations were observed for rectal cancer, with only 1 tagSNP in Smad2 and 3 tagSNP in Smad3 having 95% CIs excluding 1.0. Several Smad3 tagSNPs were only associated with CpG island methylator phenotype. We observed several statistically significant interactions between genetic variation in the TGF-β signaling pathway and NFκB1, further illustrating its involvement in proposed mechanisms. In addition, we observed statistically significant interaction between TGFβ1, TGFβR1, and Smad3 and cigarette smoking, aspirin use, and estrogen status for both colon and rectal cancers. Variation in TGFβ1, TGFβR1, and Smad3 seemed to influence survival after diagnosis of colon and rectal cancer.

Conclusions: These findings provide further support for genetic variation in the TGF-β signaling pathway and risk of developing both colon and rectal cancers.

Impact: Insight into biological pathways is provided. Cancer Epidemiol Biomarkers Prev; 20(1); 57–69. ©2011 AACR.
Generalizability and Epidemiologic Characterization of Eleven Colorectal Cancer GWAS Hits in Multiple Populations
Authors: He Jing , Wilkens Lynne R. , Stram Daniel O. , Kolonel Laurence N. , Henderson Brian E. , Wu Anna H. , Le Marchand Loic , Haiman Christopher A.
Published: January 2011

Background: Genome-wide association studies (GWAS) in populations of European ancestry have identified several loci that confer an increased risk of colorectal cancer (CRC).

Methods: We studied the generalizability of the associations with 11 risk variants for CRC on 8q23 (rs16892766), 8q24 (rs6983267), 9p24 (rs719725), 10p14 (rs10795668), 11q23 (rs3802842), 14q22 (rs4444235), 15q13 (rs4779584), 16q22 (rs9929218), 18q21 (rs4939827), 19q13 (rs10411210), and 20p12 (rs961253) in a multiethnic sample of 2,472 CRC cases, 839 adenoma cases and 4,466 controls comprised of European American, African American, Native Hawaiian, Japanese American, and Latino men and women. Because findings for CRC and adenoma were similar, we combined both groups in the analyses.

Results: We confirmed the associations with an increased risk of CRC/adenoma for the 8q24, 11q23 and 15q13 loci in European Americans, and observed significant associations between the 8q24 and 20p12 loci with CRC/adenoma risk in African Americans. Moreover, we found statistically significant cumulative effects of risk alleles on CRC/adenoma risk in all populations (odds ratio [OR] per allele = 1.07–1.09, P ≤ 0.039) except in Japanese Americans (OR = 1.01, P = 0.52). We found heterogeneity in the associations by tumor subsite, age of CRC/adenoma onset, sex, body mass index (BMI), and smoking status for some of the variants.

Conclusions: These results provide evidence that the known variants are in aggregate significantly associated with CRC/adenoma risk in multiple populations except Japanese Americans, and the influences may differ across groups defined by clinicopathological characteristics for some variants.

Impact: These results underline the importance of studying the epidemiologic architecture of these genetic effects in large and diverse populations. Cancer Epidemiol Biomarkers Prev; 20(1); 70–81. ©2011 AACR.
Race-Specific Impact of Natural History, Mammography Screening, and Adjuvant Treatment on Breast Cancer Mortality Rates in the United States
Authors: van Ravesteyn Nicolien T. , Schechter Clyde B. , Near Aimee M. , Heijnsdijk Eveline A.M. , Stoto Michael A. , Draisma Gerrit , de Koning Harry J. , Mandelblatt Jeanne S.
Published: January 2011

Background: U.S. Black women have higher breast cancer mortality rates than White women despite lower incidence. The aim of this study is to investigate how much of the mortality disparity can be attributed to racial differences in natural history, uptake of mammography screening, and use of adjuvant therapy.

Methods: Two simulation models use common national race, and age-specific data for incidence, screening and treatment dissemination, stage distributions, survival, and competing mortality from 1975 to 2010. Treatment effectiveness and mammography sensitivity are assumed to be the same for both races. We sequentially substituted Black parameters into the White model to identify parameters that drive the higher mortality for Black women in the current time period.

Results: Both models accurately reproduced observed breast cancer incidence, stage and tumor size distributions, and breast cancer mortality for White women. The higher mortality for Black women could be attributed to differences in natural history parameters (26–44%), use of adjuvant therapy (11–19%), and uptake of mammography screening (7–8%), leaving 38% to 46% unexplained.

Conclusion: Black women appear to have benefited less from cancer control advances than White women, with a greater race-related gap in the use of adjuvant therapy than screening. However, a greater portion of the disparity in mortality appears to be due to differences in natural history and undetermined factors.

Impact: Breast cancer mortality may be reduced substantially by ensuring that Black women receive equal adjuvant treatment and screening as White women. More research on racial variation in breast cancer biology and treatment utilization is needed. Cancer Epidemiol Biomarkers Prev; 20(1); 112–22. ©2011 AACR.
Joint Effects of Dietary Vitamin D and Sun Exposure on Breast Cancer Risk: Results from the French E3N Cohort
Authors: Engel Pierre , Fagherazzi Guy , Mesrine Sylvie , Boutron-Ruault Marie-Christine , Clavel-Chapelon Francoise
Published: January 2011

Background: Ecological studies have suggested that vitamin D production through ultraviolet (UV) solar irradiance could reduce breast cancer (BC) risk. Although studies restricted to dietary vitamin D intake have provided inconsistent results, little is known about the relationship between pre- and postmenopausal BC and combined intakes from diet, supplements, and sun exposure.

Methods: Cox proportional hazards regression models evaluated the association between vitamin D intakes, mean daily ultraviolet radiation dose (UVRd) at the place of residence and risk of BC among 67,721 women of the French E3N cohort. All analyses were stratified on menopausal status taking into account important confounders including calcium consumption.

Results: During 10 years of follow-up, a total of 2,871 BC cases were diagnosed. Dietary and supplemental vitamin D intakes were not associated with BC risk; however, in regions with the highest UVRd, postmenopausal women with high dietary or supplemental vitamin D intake had a significantly lower BC risk as compared with women with the lowest vitamin D intake (HR = 0.68, 95% CI: 0.54–0.85, and HR = 0.57, 95% CI: 0.36–0.90, respectively).

Conclusion: Our results suggest that a threshold of vitamin D exposure from both sun and diet is required to prevent BC and this threshold is particularly difficult to reach in postmenopausal women at northern latitudes where quality of sunlight is too poor for adequate vitamin D production.

Impact: Prospective studies should further investigate associations between BC risk, vitamin D status and sunlight exposure. Cancer Epidemiol Biomarkers Prev; 20(1); 187–98. ©2011 AACR.
Spliceosome-Mediated RNA Trans-Splicing Facilitates Targeted Delivery of Suicide Genes to Cancer Cells
Authors: Gruber Christina , Gratz Iris K. , Murauer Eva M. , Mayr Elisabeth , Koller Ulrich , Bruckner-Tuderman Leena , Meneguzzi Guerrino , Hintner Helmut , Bauer Johann W.
Published: January 2011

Patients suffering from recessive dystrophic epidermolysis bullosa (RDEB), a hereditary blistering disease of epithelia, show susceptibility to develop highly aggressive squamous cell carcinoma (SCC). Tumors metastasize early and are associated with mortality in the 30th–40th years of life in this patient group. So far, no adequate therapy is available for RDEB SCC. An approach is suicide gene therapy, in which a cell death-inducing agent is introduced to cancer cells. However, lack of specificity has constrained clinical application of this modality. Therefore, we used spliceosome-mediated RNA trans-splicing technology, capable of replacing a tumor-specific transcript with one encoding a cell death-inducing peptide/toxin, to provide tumor-restricted expression. We designed 3′ pre–trans-splicing molecules (PTM) and evaluated their efficiency to trans-splice an RDEB SCC-associated target gene, the matrix metalloproteinase-9 (MMP9), in a fluorescence-based test system. A highly efficient PTM was further adapted to insert the toxin streptolysin O (SLO) of Streptococcus pyogenes into the MMP9 gene. Transfection of RDEB SCC cells with the SLO-PTM resulted in cell death and induction of toxin function restricted to RDEB SCC cells. Thus, RNA trans-splicing is a suicide gene therapy approach with increased specificity to treat highly malignant SCC tumors. Mol Cancer Ther; 10(2); 233–41. ©2011 AACR.