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  • EXPRESSION  (14)
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  • 1
    Keywords: treatment ; ASSOCIATION ; polymorphism ; POLYMORPHISMS ; single nucleotide polymorphism ; SUSCEPTIBILITY ; VARIANTS ; SKIN ; mechanisms ; prevention ; HEALTH ; PROMOTER ; BREAST ; breast cancer ; BREAST-CANCER ; cancer prevention ; smoking ; SNP ; REPAIR ; WOMEN ; LYMPHOCYTES ; DAMAGE ; GENOTYPES ; cancer risk ; CANCER-PATIENTS ; INDIVIDUALS ; case-control studies ; DNA-DAMAGE ; CANCER PATIENTS ; SUSCEPTIBILITY GENE ; BODY ; RISK ; GENE ; ENZYMES ; DISEASE ; lung cancer ; LUNG-CANCER ; PATIENT ; MECHANISM ; DNA ; TUMORS ; validation ; DRUG ; RNA ; GENES ; THERAPY ; VITRO ; LUNG ; COMBINATION ; CANCER ; EXPRESSION ; IN-VITRO ; CELLS ; CELL ; tumor ; AGENTS ; radiotherapy ; NSCLC ; CANCER-RISK ; cancer research ; RNA EXPRESSION ; ENZYME ; case control studies ; analysis ; GENOTYPE ; PROFILES ; single-nucleotide ; development ; PROMOTER POLYMORPHISM ; XRCC1 ; VARIANT ; WEIGHT ; SINGLE NUCLEOTIDE POLYMORPHISMS ; SNPs ; case-control study ; GEMCITABINE ; CAPACITY ; DEFICIENCY ; small cell lung cancer ; AGENT ; SINGLE ; DNA repair ; MPO ; APE1
    Abstract: Cells in the body are permanently attacked by DNA-reactive species, both from intracellular and environmental sources. Inherited and acquired deficiencies in host defense mechanisms against DNA damage (metabolic and DNA repair enzymes) can modify cancer susceptibility as well as therapy response. Genetic profiles should help to identify high-risk individuals who subsequently can be enrolled in preventive measures or treated by tailored therapy regimens. Some of our attempts to define such risk profiles are presented. Cancer susceptibility: Single nucleotide polymorphisms (SNPs) in metabolic and repair genes were investigated in a hospital-based lung cancer case-control study. When evaluating the risk associated with different genotypes for N-acetyltransferases (Wikman et al. 2001) and glutathione-S-transferases (Risch et al. 2001), it is mandatory to distinguish between the three major histological subtypes of lung tumors. A promoter polymorphism of the myeloperoxidase gene MPO was shown to decrease lung cancer susceptibility mainly in small cell lung cancer (SCLC) (Dally et al. 2002). The CYP3A4*1B allele was also linked to an increased SCLC risk and in smoking women increased the risk of lung cancer eightfold (Dally et al. 2003b). Polymorphisms in DNA repair genes were shown to modulate lung cancer risk in smokers, and reduced DNA repair capacity elevated the disease risk (Rajaee-Behbahani et al. 2001). Investigations of several DNA repair gene variants revealed that lung cancer risk was only moderately affected by a single variant but was enhanced up to approximately threefold by specific risk allele combinations (Popanda et al. 2004). Therapy response: Inter-individual differences in therapy response are consistently observed with cancer chemotherapeutic agents. Initial results from ongoing studies showed that certain polymorphisms in drug transporter genes (ABCB1) differentially affect response outcome in histological subgroups of lung cancer. Stronger beneficial effects were seen in non-small cell lung cancer (NSCLC) patients following gemcitabine and in SCLC patients following etoposide-based treatment. Several DNA repair parameters (polymorphisms, RNA expression, and DNA repair capacity) were measured in vitro in lymphocytes of patients before radiotherapy and correlated with the occurrence of acute side effects (radio-hypersensitivity). Our initial analysis of several repair gene variants in breast cancer patients (n = 446) who received radiotherapy revealed no association of single polymorphisms and the development of side effects (moist desquamation of the irradiated normal skin). The risk for this side effect was, however, strongly reduced in normal weight women carrying a combination of XRCC1 399Gln and APE1 148Glu alleles, indicating that these variants afford some protection against radio-hypersensitivity (Chang-Claude et al. 2005). Based on these data we conclude that specific metabolic and DNA repair gene variants can affect cancer risk and therapy outcome. Predisposition to hereditary cancer syndromes is dominated by the strong effects of some high-penetrance tumor susceptibility genes, while predisposition to sporadic cancer is influenced by the combination of multiple low-penetrance genes, of which as a major challenge, many disease-relevant combinations remain to be identified. Before translating these findings into clinical use and application for public health measures, large population-based studies and validation of the results will be required.
    Type of Publication: Book chapter
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  • 2
    Keywords: CANCER ; EXPRESSION ; carcinoma ; CELL ; Germany ; LUNG ; COMMON ; lung cancer ; LUNG-CANCER ; EXPOSURE ; RISK ; GENE ; GENES ; HYBRIDIZATION ; DNA ; MECHANISM ; primary ; RISK-FACTORS ; mechanisms ; ASSOCIATION ; polymorphism ; POLYMORPHISMS ; SUSCEPTIBILITY ; NO ; AMPLIFICATION ; AGE ; DNA-REPAIR ; REPAIR ; CIGARETTE-SMOKING ; risk factors ; smoking ; PCR ; cancer risk ; DAMAGE ; RISK FACTOR ; REGION ; CARCINOGENS ; adenocarcinoma ; case-control studies ; squamous cell carcinoma ; INDIVIDUALS ; CANCER-RESEARCH ; SMOKERS ; NUCLEOTIDE EXCISION-REPAIR ; CELL CARCINOMA ; case control study ; case-control study ; REGRESSION ; OCCUPATIONAL-EXPOSURE ; CARCINOGEN ; HEAVY ; LUNG ADENOCARCINOMA ; PIGMENTOSUM GROUP-A
    Abstract: Polymorphisms of genes coding for DNA repair can affect lung cancer risk. A common single nucleotide (-4) G-to-A polymorphism was identified previously in the 5' untranslated region of the XPA gene. In a case-control study in European Caucasians, the influence of this polymorphism on primary lung cancer risk overall and according to histologic subtypes was investigated. Four hundred sixty-three lung cancer cases (including 204 adenocarcinoma and 212 squamous cell carcinoma) and 460 tumor-free hospital controls were investigated using PCR amplification and melting point analysis of sequence-specific hybridization probes. Odds ratios (OR) were calculated by multiple logistic regression analysis adjusting for age, gender, smoking habits, and occupational exposure and showed a slightly enhanced risk for all lung cancer cases as well as for squamous cell carcinoma and adenocarcinoma cases. Gene-environment interactions were analyzed with respect to smoking and occupational exposure. A nearly 3-fold increased risk for adenocarcinoma associated with the XPA AA genotype was observed for occupationally exposed individuals (OR, 2.95; 95% confidence interval, 1.42-6.14) and for heavy smokers (OR, 2.52; 95% confidence interval, 1.17-5.42). No genotype-dependent increase in OR was found for nonexposed individuals or those smoking 〈20 pack-years. The significant effect of the XPA polymorphism in heavy smokers and occupationally exposed individuals suggests an important gene-environment interaction for the XPA gene. The underlying mechanisms as to why AA homozygotes are predisposed to lung adenocarcinoma and which specific carcinogens are involved remains to be determined
    Type of Publication: Journal article published
    PubMed ID: 15598786
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  • 3
    Keywords: CANCER ; CELLS ; EXPRESSION ; TUMORS ; COMPLEX ; prognosis ; RETINOIC ACID RECEPTORS
    Abstract: Impairment of endogenous differentiation pathways like retinoic acid (RA) signaling seems to be a central pathogenetic event in astrocytic gliomas. Among others, expression of the differentiation-promoting RA chaperon protein cellular retinoic acid binding protein 2 (CRABP2) is extenuated in high-grade gliomas. Against this background, we aimed at identifying potential pathomechanisms underlying reduced CRABP2 expression in these tumors. Employing MassARRAY methylation analysis we detected extensive CpG methylation upstream of the CRABP2 gene locus in a study sample comprising 100 astrocytic gliomas of WHO grade II to IV. Compared to non-tumorous control samples tumors revealed increased CpG methylation and methylation levels were inversely correlated to CRABP2 mRNA expression. Substantiating our in situ findings, CRABP2 mRNA levels increased in glioma cell lines after exposure to the demethylating agent 5-aza-2'-deoxycytidine. Finally, a distinct CpG methylation signature distinguished between primary glioblastoma on the one hand and the group of astrocytoma WHO II-III and secondary glioblastoma on the other hand. Altogether, our observations suggest that epigenetic silencing of CRABP2 might contribute to an immature phenotype in glioma cells.
    Type of Publication: Journal article published
    PubMed ID: 22275178
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  • 4
    Keywords: EXPRESSION ; IONIZING-RADIATION ; SURVIVAL ; tumor ; DIAGNOSIS ; FOLLOW-UP ; COHORT ; GLUTATHIONE ; METALLOTHIONEIN ; GENOME-WIDE ASSOCIATION
    Abstract: We assessed whether variants in 22 oxidative stress-related genes are associated with mortality of breast cancer patients and whether the associations differ according to radiotherapy. Using a prospective cohort of 1348 postmenopausal breast cancer patients, we estimated hazard ratios (HR) and 95% confidence intervals (CI) for 109 single nucleotide polymorphisms (SNPs) using Cox proportional hazards regression. Validation of results was attempted using two Scandinavian studies. Eleven SNPs in MT2A, NFE2L2, NQO1, PRDX1, and PRDX6 were significantly associated with overall mortality after a median follow-up of 5.7 years. Three SNPs in NQO1 (rs2917667) and in PRDX6 (rs7314, rs4916362) were consistently associated with increased risk of dying across all three study populations (pooled: HRNQO1_rs2917667 1.20, 95% CI 1.00-1.44, p = 0.051; HRPRDX6_rs7314 1.16, 95% CI 1.00-1.35, p = 0.056, HRPRDX6_rs4916362 1.14 95% CI 1.00-1.32, p = 0.062). Potential effect modification by radiotherapy was found for CAT_rs769218. In conclusion, genetic variants in NQO1 and PRDX6 may modify breast cancer prognosis.
    Type of Publication: Journal article published
    PubMed ID: 23489758
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  • 5
    Keywords: ANGIOGENESIS ; CELLS ; EXPRESSION ; ENDOTHELIAL GROWTH-FACTOR ; INHIBITION ; POPULATION ; PROTEIN ; mechanisms ; DOWN-REGULATION ; HYPERMETHYLATION ; MALIGNANT GLIOMAS ; astrocytoma ; SUBTYPES ; PROMOTER METHYLATION ; GLIOBLASTOMA ; AKAP12 ; Gravin ; SSeCKS ; SSECKS/GRAVIN/AKAP12
    Abstract: The scaffold protein A-kinase anchor protein 12 (AKAP12) exerts tumor suppressor activity and is downregulated in several tumor entities. We characterized AKAP12 expression and regulation in astrocytomas, including pilocytic and diffusely infiltrating astrocytomas. We examined 194 human gliomas and 23 normal brain white matter samples by immunohistochemistry or immunoblotting for AKAP12 expression. We further performed quantitative methylation analysis of the AKAP12 promoter by MassARRAY (R) of normal brain, World Health Organization (WHO) grade I to IV astrocytomas, and glioma cell lines. Our results show that AKAP12 is expressed in a perivascular distribution in normal CNS, strongly upregulated in tumor cells in pilocytic astrocytomas, and weakly expressed in diffuse astrocytomas of WHO grade II to IV. Methylation analyses revealed specific hypermethylation of AKAP12 alpha promoter in WHO grade II to IV astrocytomas. Restoration experiments using 5-aza-2'-deoxycytidine in primary glioblastoma cells decreased AKAP12 alpha promoter methylation and markedly increased AKAP12 alpha mRNA levels. In summary, we demonstrate that AKAP12 is differentially expressed in human astrocytomas showing high expression in pilocytic but low expression in diffuse astrocytomas of all WHO-grades. Our results further indicate that epigenetic mechanisms are involved in silencing AKAP12 in diffuse astrocytomas; however, a tumor suppressive role of AKAP12 in distinct astrocytoma subtypes remains to be determined
    Type of Publication: Journal article published
    PubMed ID: 24042196
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  • 6
    Keywords: CANCER ; CELLS ; EXPRESSION ; IRRADIATION ; radiotherapy ; CELL ; Germany ; THERAPY ; TOXICITY ; COHORT ; RISK ; SURGERY ; radiation ; PATIENT ; DNA ; INDEX ; QUALITY ; SKIN ; treatment ; BREAST ; breast cancer ; BREAST-CANCER ; LESIONS ; RADIATION-THERAPY ; ASSAY ; WOMEN ; DNA-REPAIR ; REPAIR ; COMET ASSAY ; DAMAGE ; LYMPHOCYTES ; BEAM ; DNA-DAMAGE ; PARAMETERS ; CANCER-PATIENTS ; KINETICS ; body mass index ; DNA repair ; DNA repair capacity ; PERIPHERAL-BLOOD LYMPHOCYTES ; ATAXIA-TELANGIECTASIA ; HETEROZYGOTES ; INTRINSIC RADIOSENSITIVITY ; radiation tolerance,DNA repair capacity,breast neoplasms,body mass index
    Abstract: Background and purpose: Intrinsic and extrinsic factors can affect the occurrence of side effects of radiotherapy. The influence of therapy modalities, personal characteristics and individual DNA repair capacity on the risk of acute skin toxicity was thus evaluated.Materials and methods: In a prospective study of 478 female breast cancer patients receiving adjuvant radiotherapy of the breast after breast-conserving surgery, acute skin toxicity was documented systematically using a modified version of the common toxicity criteria. Prognostic personal and treatment characteristics were identified for the entire cohort. Individual DNA repair capacity was determined in a subgroup of 113 patients with alkaline comet assay using phytohemagglutinin stimulated lymphocytes. Using proportional hazards analysis to account for cumulative biologically effective radiation dose, the hazard for the development of acute skin reactions (moist desquamation) associated with DNA repair capacity was modeled.Results: Of the 478 participants, 84 presented with acute reactions by the end of treatment. Higher body mass index was significantly associated with an increased risk for acute reactions (hazard ratio = 1.09 per 1 kg/m(2)), adjusted for treating hospital and photon beam quality. The comet assay parameters examined, including background DNA damage in non-irradiated cells, DNA damage induced by 5 Gy, and DNA repair capacity, were not significantly associated with risk of acute skin toxicity.Conclusions: Higher BMI is predictive of acute skin toxicity, however, individual repair parameters as determined by the alkaline comet assay are not informative enough. More comprehensive analyses including late effects of radiotherapy and repair kinetics optimized for different radiation-induced DNA lesions are warranted. (C) 2003 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 14643951
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  • 7
    Keywords: CANCER ; EXPRESSION ; tumor ; BLOOD ; CELL LUNG-CANCER ; Germany ; PROSTATE ; THERAPY ; SUPPORT ; RISK ; DISTINCT ; GENE ; GENE-EXPRESSION ; GENES ; RNA ; transcription ; PATIENT ; DNA ; MESSENGER-RNA ; MARKER ; IMPACT ; primary ; prognosis ; RISK-FACTORS ; CARCINOGENESIS ; ASSOCIATION ; polymorphism ; POLYMORPHISMS ; VARIANTS ; lifestyle ; DIFFERENCE ; PLASMA ; REPAIR ; risk factors ; COLORECTAL-CANCER ; prostate cancer ; PROSTATE-CANCER ; MARKERS ; LYMPHOCYTES ; MDM2 ; CANCER-PATIENTS ; POLYMERASE-CHAIN-REACTION ; PREDICTION ; CANCER PATIENTS ; PERIPHERAL-BLOOD ; POLYMERASE CHAIN-REACTION ; NUCLEOTIDE EXCISION-REPAIR ; DNA repair ; TP53 ; BETA-CAROTENE ; molecular ; CHAIN ; ONCOLOGY ; REGRESSION ; RE ; TUMOR-SUPPRESSOR ; VARIANT ; THERAPIES ; mRNA ; LEVEL ; SUPPRESSOR ; GENOTYPE ; HAPLOTYPE ; OXIDATIVE DNA-DAMAGE ; RISK-FACTOR ; ENGLAND ; COEFFICIENTS ; quantitative ; outcome ; VALUES ; tumor suppressor ; MDM2 SNP309 ; genetic variants ; treatment outcome
    Abstract: Both genetic variants and messenger RNA (mRNA) expression of DNA repair and tumor suppressor genes have been investigated as molecular markers for therapy outcome. However, the phenotypic impact of genetic variants often remained unclear, thus the rationale of their use in risk prediction may be limited. We therefore analyzed genetic variants together with anthropometric and lifestyle factors to see how these affect mRNA levels of ERCC1, MDM2 and TP53 in primary blood lymphocytes. mRNA expression was measured in 376 prostate cancer patients by quantitative real-time polymerase chain reaction after reverse transcription, and ERCC1 rs11615 T 〉 C, ERCC1 rs3212986 C 〉 A, MDM2 rs2279744 T 〉 G and TP53 rs17878362 (p53PIN3) polymorphisms were determined. Considerable interindividual differences in mRNA expression were found (coefficients of variation: ERCC1, 45%; MDM2, 43% and TP53, 35%). ERCC1 expression was positively correlated with plasma levels of beta-carotene (P = 0.03) and negatively correlated with canthaxanthin (P = 0.02) and lutein (P = 0.02). Overall, the polymorphisms affected mRNA expression only weakly. Carriers of a distinct ERCC1 haplotype (CC) showed, however, significantly lower expression values than non-carriers (P = 0.001). Applying logistic regression, we found that CC haplotype carriers had a 1.69-fold increased odds ratio (95% confidence interval: 1.06-2.71) for reduced ERCC1 mRNA levels. This low ERCC1 expression might be associated with reduced DNA repair and better therapy response. In summary, the association we have found between ERCC1 genotype and mRNA expression supports recent clinical observations that genetic variation in ERCC1 can affect treatment outcome and prognosis. Our study further revealed a modulating effect by nutritional factors
    Type of Publication: Journal article published
    PubMed ID: 18332046
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  • 8
    Keywords: CANCER ; CELLS ; EXPRESSION ; IN-VITRO ; IRRADIATION ; radiotherapy ; Germany ; THERAPY ; NEW-YORK ; RISK ; SURGERY ; radiation ; PATIENT ; DNA ; DONOR ; RISK-FACTORS ; INDUCTION ; SKIN ; fibroblasts ; SUSCEPTIBILITY ; BREAST ; breast cancer ; BREAST-CANCER ; RADIATION-THERAPY ; ASSAY ; DNA-REPAIR ; REPAIR ; REPRODUCIBILITY ; risk factors ; cancer risk ; COMET ASSAY ; DAMAGE ; LYMPHOCYTES ; DNA repair ; radiation sensitivity ; alkaline single-cell microgel electrophoresis assay ; CELLULAR RADIOSENSITIVITY ; CHROMOSOMAL RADIOSENSITIVITY ; DNA repair capacity ; DOUBLE-STRAND BREAKS ; IN-VITRO RADIOSENSITIVITY ; NORMAL-TISSUE RADIOSENSITIVITY ; PERIPHERAL-BLOOD LYMPHOCYTES ; radiation effects ; radiosensitivity ; TELANGIECTASIA
    Abstract: Purpose: Repair of radiation-induced DNA damage plays a critical role for both the susceptibility of patients to side effects after radiotherapy and their subsequent cancer risk. The study objective was to evaluate whether DNA repair data determined in vitro are correlated with the occurrence of acute side effects during radiotherapy. Methods and Materials: Breast cancer patients receiving radiation therapy after a breast- conserving surgery were recruited in a prospective epidemiologic study. As an indicator for clinical radiosensitivity, adverse reactions of the skin were recorded. Cryo-preserved lymphocytes from 113 study participants were gamma-irradiated with 5 Gy in vitro and analyzed using the alkaline comet assay. Reproducibility of the assay was determined by repeated analysis (n = 26) of cells from a healthy donor. A coefficient of variation of 0.3 was calculated. Results: The various parameters determined to characterize the individual DNA repair capacity showed large differences between patients. Eleven patients were identified with considerably enhanced DNA damage induction, and 7 patients exhibited severely reduced DNA repair capacity after 15 and 30 min. Six patients were considered as clinically radiosensitive, indicated by moist desquamation of the skin after a total radiation dose of about 50 Gy. Conclusions: Using the alkaline comet assay as described here, breast cancer patients were identified showing abnormal cellular radiation effects, but this repair deficiency corresponded only at a very limited extent to the acute radiation sensitivity of the skin. Because impaired DNA repair could be involved in the development of late irradiation effects, individuals exhibiting severely reduced DNA repair capacity should be followed for the development of late clinical symptoms. (C) 2003 Elsevier Science Inc
    Type of Publication: Journal article published
    PubMed ID: 12654430
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  • 9
    Keywords: CANCER ; EXPRESSION ; IN-VITRO ; IONIZING-RADIATION ; radiotherapy ; BLOOD ; Germany ; THERAPY ; TOXICITY ; RISK ; GENE ; GENES ; transcription ; radiation ; PATIENT ; RESPONSES ; DNA ; RISK-FACTORS ; PATTERNS ; DNA-REPAIR ; REPAIR ; risk factors ; prostate cancer ; PROSTATE-CANCER ; PCR ; DAMAGE ; LYMPHOCYTES ; PROBES ; DNA-DAMAGE ; CANCER-PATIENTS ; RT-PCR ; INTENSITY-MODULATED RADIOTHERAPY ; sensitivity ; CANCER PATIENTS ; PERIPHERAL-BLOOD ; DNA repair ; CONSTITUTIVE EXPRESSION ; NORMAL-TISSUE RADIOSENSITIVITY ; PERIPHERAL-BLOOD LYMPHOCYTES ; radiosensitivity ; CLUSTER ; BRCA2 ; GRADE ; CLUSTER-ANALYSIS ; LEVEL ; DNA damage ; cluster analysis ; PROFILES ; EXPRESSION PATTERNS ; CRITERIA ; HUMAN-CELLS ; prospective ; GAMMA-IRRADIATION ; RISK-FACTOR ; SKIN REACTIONS ; peripheral blood ; GENOTOXIC STRESS ; gene expression profiles ; radio-resistance
    Abstract: Purpose: Repair of radiation-induced DNA damage is believed to play a critical role in the development of adverse reactions in radiotherapy patients. Constitutive mRNA expression of repair genes was investigated in such patients to analyze whether expression patterns are predictive for therapy-related acute side effects. Materials and methods: Prostate cancer patients (n = 406) receiving intensity-modulated radiotherapy were recruited in a prospective epidemiological study. Adverse effects were monitored during therapy using common toxicity criteria. For expression analyses, samples from 58 patients were selected according to their observed grade of clinical side effects to radiotherapy. Expression profiles were generated from peripheral blood lymphocytes using customized cDNA-arrays which carried probes for 143 DNA repair or repair-related genes. In addition, expression of selected genes was confirmed by quantitative real-time reverse transcription PCR (RT-PCR). Constitutive mRNA expression profiles were analyzed for predicting acute clinical radiosensitivity or radio-resistance. Results: Cluster analysis identified 19 differentially expressed genes. Many of these genes are involved in DNA double strand break repair. Expression levels of these genes differed up to 7-fold from the mean of all patients whereas expression levels of housekeeping genes varied only up to 2-fold. High expression of the identified genes was associated with a lack of clinical radiation sensitivity thus indicating radio-resistance. Conclusions: Constitutive expression of DNA repair-related genes may affect the development of acute side effects in radiotherapy patients, and high expression levels of these genes seem to support protection from adverse reactions
    Type of Publication: Journal article published
    PubMed ID: 16966187
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  • 10
    Keywords: CANCER ; CELLS ; EXPRESSION ; IN-VITRO ; IONIZING-RADIATION ; radiotherapy ; CELL ; Germany ; PROSTATE ; TOXICITY ; VITRO ; COMMON ; RISK ; GENE ; GENES ; transcription ; radiation ; TIME ; PATIENT ; DNA ; RISK-FACTORS ; INDUCTION ; STRESS ; DNA-REPAIR ; REPAIR ; risk factors ; smoking ; prostate cancer ; PROSTATE-CANCER ; MODULATION ; PCR ; DAMAGE ; LYMPHOCYTES ; DNA-DAMAGE ; CANCER-PATIENTS ; side effects ; CANCER PATIENTS ; real-time PCR ; NUCLEOTIDE EXCISION-REPAIR ; DNA repair ; NORMAL-TISSUE RADIOSENSITIVITY ; PERIPHERAL-BLOOD LYMPHOCYTES ; radiosensitivity ; ONCOLOGY ; GRADE ; quantitative RT-PCR ; REAL-TIME ; development ; ionizing radiation ; DAMAGE RECOGNITION ; LEVEL ; biomarker ; INTERVAL ; analysis ; CRITERIA ; BREAST-CANCER PATIENTS ; USA ; HUMAN-CELLS ; DNA damage response ; INCREASED RISK ; NEVER SMOKERS ; odds ratio ; RISK-FACTOR ; PREDICT ; quantitative ; REPAIR GENES ; LYMPHOBLASTOID-CELLS ; GROUP-C PROTEIN
    Abstract: Repair of radiation-induced DNA damage is believed to play a critical role in developing adverse reactions during radiotherapy. Ionizing radiation induces transcription of several DNA repair genes including XPC as a part of the p53-transmitted stress response. XPC gene induction was measured to analyze whether it predicts occurrence of therapy-related acute side effects. Prostate cancer patients (n = 406) receiving radiotherapy were monitored for development of acute adverse effects using common toxicity criteria. For gene induction analysis, lymphocytes from 99 patients were selected according to their observed grade of clinical side effects. Cells were irradiated in vitro with 5 Gy and analyzed after 4 hr for XPC gene induction using reverse transcription and quantitative real-time PCR. Analysis of modulation of XPC induction by personal, clinical or lifestyle factors was included. Inter-individual induction of XPC expression by ionizing radiation varied up to 20-fold (0.29-5.77) and was significantly higher in current or exsmokers than in never-smokers (p value: 0.008). Patients with XPC induction above the 90th percentile compared to those with lower induction levels were at increased risk of suffering from adverse reactions during radiotherapy (odds ratio 5.3, 95% confidence interval 1.2-24.5; adjusted for smoking). In summary, XPC mRNA levels induced by ionizing radiation were shown for the first time to be strongly affected by smoking and to be associated with an approximately 5-fold increased risk for developing acute side effects of radiotherapy. The predictive value of DNA damage-induced XPC levels as a possible biomarker for radiosensitivity has to be further investigated. (c) 2007 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 17657713
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