Circ-camk4 involved in cerebral ischemia/reperfusion induced neuronal injury.

Stroke and subsequent cerebral ischemia/reperfusion (I/R) injury is a frequently occurring disease that can have serious consequences in the absence of timely intervention. Circular RNAs (circRNAs) in association with microRNAs (miRNAs) and RNA-binding proteins (RBPs) can influence gene expression. However, whether circRNAs have a role in cerebral I/R injury pathogenesis, especially soon after onset, is unclear. In this study, we used the SD rat middle cerebral artery occlusion (MCAO) model of stroke to examine the role of circRNAs in cerebral I/R injury. We used high-throughput sequencing (HTS) to compare the expression levels of circRNAs in cerebral cortex tissue from MCAO rats during the occlusion-reperfusion latency period 3 hours after I/R injury with those in control cerebral cortices. Our sequencing results revealed that expression levels of 44 circRNAs were significantly altered after I/R, with 16 and 28 circRNAs showing significant up- and down-regulation, respectively, relative to levels in control cortex. We extended these results in vitro in primary cultured neuron cells exposed to oxygen-glucose deprivation/reperfusion (OGD/R) using qRT-PCR to show that levels of circ-camk4 were increased in OGD/R neurons relative to control neurons. Bioinformatics analyses predicted that several miRNAs could be associated with circ-camk4 and this prediction was confirmed in a RNA pull-down assay. KEGG analysis to predict pathways that involve circ-camk4 included the glutamatergic synapse pathway, MAPK signaling pathway, and apoptosis signaling pathways, all of which are known to be involved in brain injury after I/R. Our results also demonstrate that levels of the human homolog to circ-camk4 (hsa-circ-camk4) are elevated in SH-SY5Y cells exposed to OGD/R treatment. Overexpression of hsa-circ-camk4 in SH-SY5Y cells significantly increased the rate of cell death after OGD/R, suggesting that circ-camk4 may play a key role in progression of cerebral I/R injury.

Magnetic gold nanocomposite and aptamer assisted triple recognition electrochemical immunoassay for determination of brain natriuretic peptide.

A triple recognition voltammetric method for the determination of brain natriuretic peptide (BNP) is described. Gold nanoparticles (AuNPs) and magnetic nanoparticles (MagNPs), sized 26 and 310 nm, respectively, were synthesized and characterized by transmission electron microscopy (TEM), FT-IR, dynamic light scattering (DLS), and Z-potential measurements. Antibody-modified MagNPs and methylene blue-labeled aptamer (Apt-MB)-modified AuNPs were used as an identifier, a signal reporter, and an amplifier, respectively. In the presence of BNP, the magnetic gold nanocomposite is formed through cascade conjugation via specific interaction. It then hybridized with complementary DNA (cDNA) on the interface, thereby amplifying the current signal of Apt-MB and increasing the selectivity of the immunoassay. Results obtained demonstrate the development of a highly selective method with a detection limit of 0.56 pg mL-1 and a linear response over the concentration range 1-10,000 pg mL-1. The standard deviation of the method is < 6% while the recovery ranged from 92.2 to 104.2%. Graphical abstract Schematic representation of triple recognition electrochemical immunosensor based on two functionalized nanoparticles (antibody-modified magnetic nanoparticle (MNP-Ab) and aptamer-modified gold nanoparticle (AuNPs-Apt)) for determination of brain natriuretic peptide (BNP).

Copy Number Aberrations of Multiple Genes Identified as Prognostic Markers for Extrahepatic Metastasis-free Survival of Patients with Hepatocellular Carcinoma.

Extrahepatic metastasis confers unfavorable patient prognosis in patients with hepatocellular carcinoma (HCC), however, reliable markers allowing prediction of extrahepatic metastasis at the time of initial diagnosis are still lacking. This study was to identify gene-level copy number aberrations (CNAs) related to extrahepatic metastasis-free survival of HCC patients, and further examine the associations between CNAs and gene expression. Array comparative genomic hybridization (aCGH) and expression array were used to analyze gene CNAs and expression levels, respectively. The associations between CNAs of a panel of 20 genes and extrahepatic metastasis-free survival were analyzed in 66 patients with follow-up period of 1.6-90.5 months. The gene expression levels between HCCs with and without gene CNA were compared in 109 patients with HCC. We observed that gains at MDM4 and BCL2L1, and losses at APC and FBXW7 were independent prognostic markers for extrahepatic metastasis-free survival of HCC patients. Integration analysis of aCGH and expression data showed that MDM4 and BCL2L1 were significantly upregulated in HCCs with gene gain, while APC and FBXW7 were significantly downregulated in HCCs with gene loss. We concluded that gene gains at MDM4 and BCL2L1, and losses at APC and FBXW7, with concordant expression changes, were associated with extrahepatic metastasis-free survival of HCC patients and have potential to act as novel prognostic markers.

A Panel of Genes Identified as Targets for 8q24.13-24.3 Gain Contributing to Unfavorable Overall Survival in Patients with Hepatocellular Carcinoma.

Copy number aberrations (CNAs) in chromosome arm 8q have been associated with unfavorable clinical outcomes of several cancers and progressive tumor characteristics of hepatocellular carcinoma (HCC). This study was to identify correlation of CNAs in 8q with clinical outcomes of HCC patients, and further screen for differentially expressed genes in outcome-related CNAs. Array comparative genomic hybridization and expression arrays were performed to detect CNAs and expression levels, respectively. The correlations between CNAs in 8q and outcomes were analyzed in 66 patients, with a median follow-up time of 45.0 months (range, 2.6-108.6 months). One hundred and nine cases were further evaluated to identify differentially expressed genes in the potential outcome-related CNAs. Copy number gain in 8q was observed in 22 (33.3%) of the 66 HCC cases. The most recurrent gains (with frequencies >20%) were 8q13.3-21.3,8q21.3-23.3,8q23.3-24.13,8q24.13-24.3, and 8q24.3. Survival analysis showed that 8q24.13-24.3 gain was significantly associated with reduced overall survival (jP=0.010). Multivariate Cox analysis identified 8q24.13-24.3 gain as an independent prognostic factor for poor overall survival (HR=2.47; 95% CI=1.16-5.26; Р=0.019). Apanel of 17 genes within the 8q24.13-24.3 region, including ATAD2,SQLE,PVT1,ASAP1, and NDRG1 were significantly upregulated in HCCs with 8q24.13-24.3 gain compared to those without. These results suggest that copy number gain at 8q24.13-24.3 is an unfavorable prognostic marker for HCC patients, and the potential oncogenes ATAD2,SQLE, PVT1, ASAP1,and NDRG1 within the regional gain, may contribute coordinately to the 8q24.13-24.3 gain-related poor prognosis.

Multiple genes identified as targets for 20q13.12-13.33 gain contributing to unfavorable clinical outcomes in patients with hepatocellular carcinoma.

BACKGROUND: Recurrent chromosome 20q gain is implicated in progressive cancer behaviors and has been associated with clinical outcomes in multiple types of cancer; however, its prognostic significance in hepatocellular carcinoma (HCC) and the involved genes remain unclear. METHODS: Array comparative genomic hybridization and expression arrays were used to detect copy number alterations (CNAs) and expression levels, respectively. The associations between CNAs in 20q and outcomes were analyzed on 66 patients, for which the follow-up period was 2.6-73.3 months. One hundred seventeen tumors were further investigated to identify target genes in the potentially outcome-related CNAs. RESULTS: Regional or whole 20q gain was detected in 24 (36.4%) of the 66 HCC cases. The most recurrent gains were 20q11.21-12, 20q12-13.12, 20q13.12-13.33 and 20q13.33. Of the CNAs, 20q13.12-13.33 gain was significantly associated with reduced extrohepatic metastasis-free and overall survival, as well as with elevated postoperative AFP level, tumor vascular invasion and advanced tumor stage. Multivariate Cox analysis identified 20q13.12-13.33 gain as an independent prognostic marker for metastasis (HR 3.73, 95% CI 1.08-12.87) and death (HR 3.00, 95% CI 1.26-7.13). A panel of 19 genes in 20q13.12-13.33 was significantly overexpressed in HCCs with gain compared to HCCs without. High expression (greater than median) for 5 of the 19 genes, DDX27, B4GALT5, RNF114, ZFP64 and PFDN4, correlated significantly with vascular invasion, and high RNF114 expression also with advanced tumor stage. CONCLUSIONS: Gain at 20q13.12-13.33 is a prognostic marker of metastasis and death, and DDX27, B4GALT5, RNF114, ZFP64, and PFDN4 are probable target genes which may be involved together in the unfavorable outcomes of HCC patients.

Lifetime pesticide use and telomere shortening among male pesticide applicators in the Agricultural Health Study.

BACKGROUND: Telomere length (TL) in surrogate tissues may be influenced by environmental exposures. OBJECTIVE: We aimed to determine whether lifetime pesticides use is associated with buccal cell TL. METHODS: We examined buccal cell TL in relation to lifetime use of 48 pesticides for 1,234 cancer-free white male pesticide applicators in the Agricultural Health Study (AHS), a prospective cohort study of 57,310 licensed pesticide applicators. Participants provided detailed information on lifetime use of 50 pesticides at enrollment (1993-1997). Buccal cells were collected from 1999 to 2006. Relative telomere length (RTL) was measured using quantitative real-time polymerase chain reaction. We used linear regression modeling to evaluate the associations between specific pesticides and the logarithm of RTL, adjusting for age at buccal cell collection, state of residence, applicator license type, chewing tobacco use, and total lifetime days of all pesticide use. RESULTS: The mean RTL for participants decreased significantly in association with increased lifetime days of pesticide use for alachlor (p = 0.002), 2,4-dichlorophenoxyacetic acid (2,4-D; p = 0.004), metolachlor (p = 0.01), trifluralin (p = 0.05), permethrin (for animal application) (p = 0.02), and toxaphene (p = 0.04). A similar pattern of RTL shortening was observed with the metric lifetime intensity-weighted days of pesticide use. For dichlorodiphenyltrichloroethane (DDT), we observed significant RTL shortening for lifetime intensity-weighted days (p = 0.04), but not for lifetime days of DDT use (p = 0.08). No significant RTL lengthening was observed for any pesticide. CONCLUSION: Seven pesticides previously associated with cancer risk in the epidemiologic literature were inversely associated with RTL in buccal cell DNA among cancer-free pesticide applicators. Replication of these findings is needed because we cannot rule out chance or fully rule out bias.

Sex-related differences in DNA copy number alterations in hepatitis B virus-associated hepatocellular carcinoma.

BACKGROUND: Males have a higher prevalence of hepatocellular carcinoma (HCC) than females in general, but the reasons for the sex disparity are still obscure. DNA copy number alteration (CNA) is a major feature of solid tumors including HCC, but whether CNA plays a role in sex-related differences in HCC development has never been evaluated. METHODS: High-resolution array comparative genomic hybridization (CGH) was used to examine 17 female and 46 male HCC patients with chronic hepatitis B virus (HBV) infection in Shanghai, China. Two-tailed Fisher's exact or chi2 tests was used to compare CNAs between females and males. RESULTS: The overall frequencies and patterns of CNAs in female and male cases were similar. However, female HCC tumors presented more copy number gains compared to those in males on 1q21.3-q22 (76.5% vs. 37.0%, P = 0.009), 11q11 (35.3% vs. 0.0%, P = 0.0002) and 19q13.31-q13.32 (23.5% vs. 0.0%, P = 0.004), and loss on 16p11.2 (35.3% vs. 6.5%, P = 0.009). Relative to females, male cases had greater copy number loss on 11q11 (63.0% vs. 17.6%, P = 0.002). Further analyses showed that 11q11 gain correlated with 19q13.31-q13.32 gain (P = 0.042), 11q11 loss (P = 0.011) and 16p11.2 loss (P = 0.033), while 1q21.3-q22 gain correlated with 19q13.31-q13.32 gain (P = 0.046). CONCLUSIONS: These findings suggest that CNAs may play a role in sex-related differences in HBV-associated HCC development.

A modified extraction method of circulating free DNA for epidermal growth factor receptor mutation analysis.

PURPOSE: Circulating free DNA (cfDNA) in plasma is promising to be a surrogate for tumor tissue DNA. However, not all epidermal growth factor receptor (EGFR) mutations in tumor tissue DNA has been detected in matched cfDNA, at least partly due to inefficient cfDNA extraction method. The purpose of this study was to establish an efficient plasma cfDNA extraction protocol. MATERIALS AND METHODS: The yield of plasma cfDNA extracted by our modified phenol-chloroform (MPC) method from non-small-cell lung cancer (NSCLC) patients was compared with that by QIAamp MinElute Virus Spin kit (Qiagen kit) as control, using the Wilcoxon rank-sum test. TaqMan quantitative polymerase chain reaction (qPCR) assays were used to quantify the plasma cfDNA extracted. Both Mutant-enriched PCR (ME-PCR) coupled sequencing and DxS EGFR mutation test kit were used to evaluate the impact of extraction method on EGFR mutation analysis. RESULTS: MPC method extracted more plasma cfDNA than Qiagen kit method (p=0.011). The proportion of longer fragment (≥ 202 bp) in cfDNA extracted by MPC method was significantly higher than by Qiagen kit method (p=0.002). In the sequencing maps of ME-PCR products, a higher mutant peak was observed on plasma cfDNA extracted by MPC method than by Qiagen kit method. In DxS EGFR mutation test kit results, plasma cfDNA extracted by MPC method contained more tumor-origin DNA than by Qiagen kit method. CONCLUSION: An improved plasma cfDNA extraction method of MPC is provided, which will be beneficial for EGFR mutation analysis for patients with NSCLC.

Predictors of global methylation levels in blood DNA of healthy subjects: a combined analysis.

BACKGROUND: Estimates of global DNA methylation from repetitive DNA elements, such as Alu and LINE-1, have been increasingly used in epidemiological investigations because of their relative low-cost, high-throughput and quantitative results. Nevertheless, determinants of these methylation measures in healthy individuals are still largely unknown. The aim of this study was to examine whether age, gender, smoking habits, alcohol drinking and body mass index (BMI) are associated with Alu or LINE-1 methylation levels in blood leucocyte DNA of healthy individuals. METHODS: Individual data from five studies including a total of 1465 healthy subjects were combined. DNA methylation was quantified by PCR-pyrosequencing. RESULTS: Age [ß = -0.011% of 5-methyl-cytosine (%5 mC)/year, 95% confidence interval (CI) -0.020 to -0.001%5 mC/year] and alcohol drinking (ß = -0.214, 95% CI -0.415 to -0.013) were inversely associated with Alu methylation. Compared with females, males had lower Alu methylation (ß = -0.385, 95% CI -0.665 to -0.104) and higher LINE-1 methylation (ß = 0.796, 95% CI 0.261 to 1.330). No associations were found with smoking or BMI. Percent neutrophils and lymphocytes in blood counts exhibited a positive (ß = 0.036, 95% CI 0.010 to 0.061) and negative (ß = -0.038, 95% CI -0.065 to -0.012) association with LINE-1 methylation, respectively. CONCLUSIONS: Global methylation measures in blood DNA vary in relation with certain host and lifestyle characteristics, including age, gender, alcohol drinking and white blood cell counts. These findings need to be considered in designing epidemiological investigations aimed at identifying associations between DNA methylation and health outcomes.

Frequent germline mutation in the BRCA2 gene in esophageal squamous cell carcinoma patients from a low-risk Chinese population.

BACKGROUND: The incidence of esophageal squamous cell cancer (ESCC) is strikingly variable by geographic area, which reflect different exposures to risk factors, including genetic predisposition. Previous studies of ESCC patients from several high-risk populations suggested that BRCA2 might play a role in the etiology. This study was conducted to screen for mutations of BRCA2 gene in ESCC cases from a low-risk population. METHODS: Forty-seven ESCC patients from a low-risk area of Southeast China were screened for mutations in the entire coding region of the BRCA2 gene by direct sequencing. RESULTS: No somatic mutations were observed in tumors. In total, 9 germline missense point mutations, each in one patient, were identified in male sporadic patients, with a mutation frequency of 19%. Of the 9 mutations, 7 were of heterozygous, while the remaining 2 were homozygous. Screening of an additional 94 healthy controls for the 9 mutations identified in ESCC cases showed that there was only 2 (2%) positive individuals, each carrying one of the mutations. Thus the mutation frequency in ESCC cases (19%) was significantly higher than that in healthy controls (OR = 10.9, 95% CI = 2.2-52.8, P = 0.003). No significant associations were observed for germline BRCA2 mutations with age, sex, cigarette smoking, alcohol drinking and family history of cancer. CONCLUSION: This series of cases from a low-risk Chinese population presented the highest frequency of germline BRCA2 mutations in ESCC reported to date, highlighting possible etiology roles in this population.

Improved Statistical Analysis for Array CGH-Based DNA Copy Number Aberrations.

Array-based comparative genomic hybridization (aCGH) allows measuring DNA copy number at the whole genome scale. In cancer studies, one may be interested in identifying DNA copy number aberrations (CNAs) associated with certain clinicopathological characteristics such as cancer metastasis. We proposed to define test regions based on copy number pattern profiles across multiple samples, using either smoothed log(2)-ratio or discrete data of copy number gain/loss calls. Association test performed on the refined test regions instead of the probes has improved power due to reduced number of tests. We also compared three types of measurement of copy number levels, normalized log(2)-ratio, smoothed log(2)-ratio, and copy number gain or loss calls in statistical hypothesis testing. The relative strengths and weaknesses of the proposed method were demonstrated using both simulation studies and real data analysis of a liver cancer study.

Association of hypomethylation of LINE-1 repetitive element in blood leukocyte DNA with an increased risk of hepatocellular carcinoma.

Global DNA hypomethylation has been associated with increased risk for cancers of the colorectum, bladder, breast, head and neck, and testicular germ cells. The aim of this study was to examine whether global hypomethylation in blood leukocyte DNA is associated with the risk of hepatocellular carcinoma (HCC). A total of 315 HCC cases and 356 age-, sex- and HBsAg status-matched controls were included. Global methylation in blood leukocyte DNA was estimated by analyzing long interspersed element-1 (LINE-1) repeats using bisulfite-polymerase chain reaction (PCR) and pyrosequencing. We observed that the median methylation level in HCC cases (percentage of 5-methylcytosine (5mC)=77.7%) was significantly lower than that in controls (79.5% 5mC) (P=0.004, Wilcoxon rank-sum test). The odds ratios (ORs) of HCC for individuals in the third, second, and first (lowest) quartiles of LINE-1 methylation were 1.1 (95% confidence interval (CI) 0.7-1.8), 1.4 (95% CI 0.8-2.2), and 2.6 (95% CI 1.7-4.1) (P for trend <0.001), respectively, compared to individuals in the fourth (highest) quartile. A 1.9-fold (95% CI 1.4-2.6) increased risk of HCC was observed among individuals with LINE-1 methylation below the median compared to individuals with higher (>median) LINE-1 methylation. Our results demonstrate for the first time that individuals with global hypomethylation measured in LINE-1 repeats in blood leukocyte DNA have an increased risk for HCC. Our data provide the evidence that global hypomethylation detected in the easily obtainable DNA source of blood leukocytes may help identify individuals at risk of HCC.

Association of copy number loss of CDKN2B and PTCH1 with poor overall survival in patients with pulmonary squamous cell carcinoma.

BACKGROUND AND PURPOSE: Although lung cancer is the leading cause of cancer deaths worldwide, reliable markers allowing prediction of patient survival at the time of initial diagnosis are still lacking. Copy number alterations (CNAs) in tumor tissue DNA have been associated with tumorigenesis and malignant progression. We aimed at identification of gene-level CNAs with prognostic value for survival in pulmonary squamous cell carcinoma (SCC). METHODS: The CNA status of a panel of 44 genes was analyzed by high-resolution array comparative genomic hybridization (CGH) in 49 SCC samples. Overall survival information (median follow-up, 40 months) for the patients was collected and used to assess outcome correlations with gene CNAs. RESULTS: Survival analysis showed that both CDKN2B loss and PTCH1 loss were associated with poor survival (both P < .001, log-rank test). Multivariate Cox analysis, including CDKN2B loss and PTCH1 loss as well as age, sex, cigarette smoking status, tumor size, tumor differentiation, and TNM stage showed that CDKN2B loss (hazard ratio [HR], 17.88; 95% confidence interval [CI], 4.40-72.67; P < .001) and PTCH1 loss (HR, 10.81; 95% CI, 1.92-60.98; P = .007) were independent prognostic factors for poor survival. In addition the PTCH1 loss was more frequently found in moderately or poorly differentiated tumors than in well-differentiated tumors (P = .007). CONCLUSION: These findings suggest that 2 genes of loss, CDKN2B and PTCH1, are associated with poor overall survival in patients with SCC of the lung and may be useful as prognostic markers.

Using loss of heterozygosity of microsatellites to distinguish high-grade dysplastic nodule from early minute hepatocellular carcinoma.

BACKGROUND: It is practical significant to seek new applicable adjuvant diagnostic biomarkers to differentiate high-grade dysplastic nodule (HGDN) from well-differentiated minute hepatocellular carcinoma (w-MHCC) due to their closely overlapping morphology. METHODS: In the present study, by using microdissection-based paraffin-embedded tissues, loss of heterozygosity (LOH) patterns of a panel of 22 microsatellite (MS) markers was examined in 8 HGDN, 14 w-MHCC (≤1 cm) and 35 larger HCC (LHCC, >1 cm). RESULTS: The results revealed a stepwise increasing fractional allelic loss from HGDN, w-MHCC and LHCC (0.166±0.141, 0.377±0.198, 0.471±0.264, respectively, P=0.005). Loci-specific analyses showed that LOH on D4S415 (66.7% vs 0.0%, P=0.04), D1S507 (50.0% vs 0.0%, P=0.098), and D9S1752 (50.0% vs 0.0%, P=0.33) occurred more frequently than 50% in w-MHCC, but not in HGDN. On the other hand, LOH on D17S960, D17S1796 and D9S1749 occurred in HGDN, but not in w-MHCC. When compared with w-MHCC, LHCC had a higher LOH frequency on D17S720 (73.9% vs 36.4%, P=0.04), D17S960 (68.8% vs 0.0%, P=0.03) and D17S1796 (81.8% vs 0.0%, P=0.01). CONCLUSIONS: The present study suggests MS-LOH is a simple and specific assay for routinely diagnostic pathology. We recommend that D4S415, D1S507, D9S1752, D17S960, D17S1796 and D9S1749 can be used as the first-line markers for differential diagnosis between HGDN and w-MHCC, and D9S1748, D17S921 and D17S520 with a LOH frequency of 40%-50% in w-MHCC, but netative in HGDN, can be regarded as the second-line candidate markers.

The relationship between EGFR gain and VHL loss in lung adenocarcinoma and poor patient survival.

BACKGROUND: The prognosis of lung cancer remains poor and clinically applicable prognostic markers have not yet been satisfactory identified. Several chromosomal copy number alterations (CNAs) have been associated with metastasis, relapse, and survival of patients with lung cancer; however, no study has focused exclusively on identifying CNAs at a gene level. The aim of this study was to identify genes whose CNAs are associated with survival of patients with lung adenocarcinoma. METHODS: The CNA status of a panel of 48 genes was detected by high-resolution array comparative genomic hybridization in 56 lung adenocarcinoma samples. The follow-up time of these patients was 8.5-65.7 months. The gene CNAs were analyzed for their association with patient survival. RESULTS: Cox univariate regression analysis revealed that EGFR gain (hazard ratio (HR) 3.84, 95% confidence interval (CI) 1.62-9.10), VHL loss (HR 4.56, 95% CI 1.85-11.27) and WWOX loss (HR 4.14, 95% CI 1.60-10.69) were each associated with poor survival. Multivariate analyses including EGFR gain, VHL loss and WWOX loss, as well as the clinicopathological variables such as age, sex, tumor size, tumor differentiation and TNM stage showed that EGFR gain (HR 4.63, 95% CI 1.69-12.7) and VHL loss (HR 4.82, 95% CI 1.41-16.43) were independent prognostic factors for poor survival, whereas WWOX loss lost statistical significance. CONCLUSION: These findings suggest that EGFR gain and VHL loss are associated with poor overall survival for lung adenocarcinoma patients and may be used as prognostic markers.

Repetitive element hypomethylation in blood leukocyte DNA and cancer incidence, prevalence, and mortality in elderly individuals: the Normative Aging Study.

BACKGROUND: Global genomic hypomethylation is a common epigenetic event in cancer that mostly results from hypomethylation of repetitive DNA elements. Case-control studies have associated blood leukocyte DNA hypomethylation with several cancers. Because samples in case-control studies are collected after disease development, whether DNA hypomethylation is causal or just associated with cancer development is still unclear. METHODS: In 722 elderly subjects from the Normative Aging Study cohort, we examined whether DNA methylation in repetitive elements (Alu, LINE-1) was associated with cancer incidence (30 new cases, median follow-up: 89 months), prevalence (205 baseline cases), and mortality (28 deaths, median follow-up: 85 months). DNA methylation was measured by bisulfite pyrosequencing. RESULTS: Individuals with low LINE-1 methylation (

Airborne particulate matter and mitochondrial damage: a cross-sectional study.

UNLABELLED: Oxidative stress generation is a primary mechanism mediating the effects of Particulate Matter (PM) on human health. Although mitochondria are both the major intracellular source and target of oxidative stress, the effect of PM on mitochondria has never been evaluated in exposed individuals. METHODS: In 63 male healthy steel workers from Brescia, Italy, studied between April and May 2006, we evaluated whether exposure to PM was associated with increased mitochondrial DNA copy number (MtDNAcn), an established marker of mitochondria damage and malfunctioning. Relative MtDNAcn (RMtDNAcn) was determined by real-time PCR in blood DNA obtained on the 1st (time 1) and 4th day (time 2) of the same work week. Individual exposures to PM10, PM1, coarse particles (PM10-PM1) and airborne metal components of PM10 (chromium, lead, arsenic, nickel, manganese) were estimated based on measurements in the 11 work areas and time spent by the study subjects in each area. RESULTS: RMtDNAcn was higher on the 4th day (mean = 1.31; 95%CI = 1.22 to 1.40) than on the 1st day of the work week (mean = 1.09; 95%CI = 1.00 to 1.17). PM exposure was positively associated with RMtDNAcn on either the 4th (PM10: beta = 0.06, 95%CI = -0.06 to 0.17; PM1: beta = 0.08, 95%CI = -0.08 to 0.23; coarse: beta = 0.06, 95%CI = -0.06 to 0.17) or the 1st day (PM10: beta = 0.18, 95%CI = 0.09 to 0.26; PM1: beta = 0.23, 95%CI = 0.11 to 0.35; coarse: beta = 0.17, 95%CI = 0.09 to 0.26). Metal concentrations were not associated with RMtDNAcn. CONCLUSIONS: PM exposure is associated with damaged mitochondria, as reflected in increased MtDNAcn. Damaged mitochondria may intensify oxidative-stress production and effects.

Association of genetic polymorphisms in STAT1 gene with increased risk of hepatocellular carcinoma.

OBJECTIVE: Although signal transducer and activator of transcription 1 (STAT1), a transcription factor, plays a critical role in carcinogenesis and has been implicated as a tumor suppressor, few studies have investigated the associations between polymorphisms of this gene and the risk of cancer development. The aim of this study was to examine whether STAT1 gene polymorphisms are associated with the risk of hepatocellular carcinoma (HCC). METHODS: Ten single nucleotide polymorphisms in the STAT1 gene were genotyped by TaqMan assays in 469 HCC cases and 558 age-, sex- and HBsAg-matched controls in a Chinese population. RESULTS: Minor allele homozygous genotypes at rs867637 (9,046 bp 3' of STP A>G), rs3771300 (IVS24-153T>G), and rs2280235 (IVS20-103G>A), compared with their homozygote genotypes of common alleles, were associated with 1.6- (95% CI 1.1-2.3), 1.6- (95% CI 1.1-2.4), and 1.4-fold (95% CI 0.95-1.9) increased risk of HCC, respectively. The GGA haplotype, comprised of risk alleles at rs867637, rs3771300 and rs2280235, conferred a 1.2-fold (95% CI 1.0-1.5) increased risk of HCC, as compared to the most common haplotype of ATG. Diplotype GGA/GGA conferred a 1.6-fold (95% CI 1.0-2.5) increased risk of HCC compared with diplotype ATG/ATG. CONCLUSION: Our results demonstrate for the first time that polymorphisms in the STAT1 gene are associated with HCC susceptibility.

Association of p53 codon 72 polymorphism with liver metastases of colorectal cancers positive for p53 overexpression.

OBJECTIVE: To evaluate the association between p53 codon 72 polymorphism (R72P) and the risk of colorectal liver metastases. METHODS: The p53 R72P genotype was identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in 78 consecutive colorectal cancer patients with liver metastases and 214 age- and sex-matched cases with nonmetastatic colorectal cancer. RESULTS: The R allele of the p53 R72P polymorphism was more frequently found in metastatic cases than in nonmetastatic cases (P=0.075). Carriers of the 72R allele had a 2.25-fold (95% CI (confidence interval)=1.05 to approximately 4.83) increased risk of liver metastases. On the stratification analysis, 72R-carrying genotype conferred a 3.46-fold (95% CI=1.02 to approximately 11.72) and a 1.05-fold (95% CI=0.36 to approximately 3.08) increased risk of liver metastases for p53 overexpression-positive and negative colorectal cancers, respectively. CONCLUSION: These results demonstrate for the first time that the 72R allele of the p53 polymorphism has an increased risk for liver metastases in colorectal cancers positive for p53 overexpression.