Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel human mammary epithelial cell line, HME348, was established from benign breast tissue from a 44-year-old germ-line BRCA2 mutation carrier with a history of stage 1 breast cancer. Mutation analysis showed that the patient had a known 6872del4 BRCA2 heterozygous mutation. The human mammary epithelial cells passaged in culture exhibited cellular replicative aging as evidenced by telomere shortening, lack of telomerase activity, and senescence. Ectopic expression of telomerase (hTERT) reconstituted telomerase activity in these cells and led to the immortalization of the cells. When grown on glass, the majority of immortalized HME348 cells expressed ESA and p63 with a small population also expressing EMA. In three-dimensional Matrigel culture, HME348 cells formed complex branching acini structures that expressed luminal (EMA, CK18) and myoepithelial (p63, CALLA, CK14) markers. Three clones derived from this culture were also p63(+)/ESA(+)/EMA(+/-) on glass but formed similar acinar structures with both luminal and myoepithelial cell differentiation in Matrigel confirming the mammary progenitor nature of these cells. Additionally, the experimentally immortalized HME348 cells formed acini in cleared mammary fat pads in vivo. As this is the first report establishing and characterizing a benign human mammary epithelial cell line derived from a BRCA2 patient without the use of viral oncogenes, these cells may be useful for the study of BRCA2 function in breast morphogenesis and carcinogenesis.
 ...
PMID:Telomerase immortalization of human mammary epithelial cells derived from a BRCA2 mutation carrier. 1654 10

Although highly penetrant alleles of BRCA1 and BRCA2 have been shown to predispose to breast cancer, the majority of breast cancer cases are assumed to result from the presence of low-moderate penetrant alleles and environmental carcinogens. Non-synonymous single nucleotide polymorphisms (nsSNPs) are hypothesised to contribute to disease susceptibility and approximately 30 per cent of them are predicted to have a biological significance. In this study, we have applied a bioinformatics-based strategy to identify breast cancer-related nsSNPs from 981 carcinogenesis-related genes expressed in breast tissue. Our results revealed a total of 367 validated nsSNPs, 109 (29.7 per cent) of which are predicted to affect the protein function (functional nsSNPs), suggesting that these nsSNPs are likely to influence the development and homeostasis of breast tissue and hence contribute to breast cancer susceptibility. Sixty-seven of the functional nsSNPs presented as commonly occurring nsSNPs (minor allele frequencies > or =5 per cent), representing excellent candidates for breast cancer susceptibility. Additionally, a non-uniform distribution of the common functional nsSNPs among different human populations was observed: 15 nsSNPs were reported to be present in all populations analysed, whereas another set of 15 nsSNPs was specific to particular population(s). We propose that the nsSNPs analysed in this study constitute a unique resource of potential genetic factors for breast cancer susceptibility. Furthermore, the variations in functional nsSNP allele frequencies across major population backgrounds may point to the potential variability of the molecular basis of breast cancer predisposition and treatment response among different human populations.
 ...
PMID:Functional nsSNPs from carcinogenesis-related genes expressed in breast tissue: potential breast cancer risk alleles and their distribution across human populations. 1659 73

Benzene is a recognized hematotoxicant and carcinogen that produces genotoxic damage. DNA double-strand breaks (DSB) are one of the most severe DNA lesions caused directly and indirectly by benzene metabolites. DSB may lead to chromosome aberrations, apoptosis and hematopoietic progenitor cell suppression. We hypothesized that genetic polymorphisms in genes involved in DNA DSB repair may modify benzene-induced hematotoxicity. We analyzed one or more single nucleotide polymorphisms (SNPs) in each of seven candidate genes (WRN, TP53, NBS1, BRCA1, BRCA2, XRCC3 and XRCC4) in a study of 250 workers exposed to benzene and 140 controls in China. Four SNPs in WRN (Ex4 -16 G > A, Ex6 +9 C > T, Ex20 -88 G > T and Ex26 -12 T > G), one SNP in TP53 (Ex4 +119 C > G) and one SNP in BRCA2 (Ex11 +1487 A > G) were associated with a statistically significant decrease in total white blood cell (WBC) counts among exposed workers. The SNPs in WRN and TP53 remained significant after accounting for multiple comparisons. One or more SNPs in WRN had broad effects on WBC subtypes, with significantly decreased granulocyte, total lymphocyte, CD4(+)-T cell, CD8(+)-T cell and monocyte counts. Haplotypes of WRN were associated with decreased WBC counts among benzene-exposed subjects. Likewise, subjects with TP53 Ex4 +119 C > G variant had reduced granulocyte, CD4(+)-T cell and B cell counts. The effect of BRCA2 Ex11 +1487 A > G polymorphism was limited to granulocytes. These results suggest that genetic polymorphisms in WRN, TP53 and BRCA2 that maintain genomic stability impact benzene-induced hematotoxicity.
Carcinogenesis 2006 Oct
PMID:Polymorphisms in genes involved in DNA double-strand break repair pathway and susceptibility to benzene-induced hematotoxicity. 1672 35

It is becoming increasingly evident that single-locus effects cannot explain complex multifactorial human diseases like cancer. We applied the multi-factor dimensionality reduction (MDR) method to a large cohort study on gene-environment and gene-gene interactions. The study (case-control nested in the EPIC cohort) was established to investigate molecular changes and genetic susceptibility in relation to air pollution and environmental tobacco smoke (ETS) in non-smokers. We have analyzed 757 controls and 409 cases with bladder cancer (n=124), lung cancer (n=116) and myeloid leukemia (n=169). Thirty-six gene variants (DNA repair and metabolic genes) and three environmental exposure variables (measures of air pollution and ETS at home and at work) were analyzed. Interactions were assessed by prediction error percentage and cross-validation consistency (CVC) frequency. For lung cancer, the best model was given by a significant gene-environment association between the base excision repair (BER) XRCC1-Arg399Gln polymorphism, the double-strand break repair (DSBR) BRCA2-Asn372His polymorphism and the exposure variable 'distance from heavy traffic road', an indirect and robust indicator of air pollution (mean prediction error of 26%, P<0.001, mean CVC of 6.60, P=0.02). For bladder cancer, we found a significant 4-loci association between the BER APE1-Asp148Glu polymorphism, the DSBR RAD52-3'-untranslated region (3'-UTR) polymorphism and the metabolic gene polymorphisms COMT-Val158Met and MTHFR-677C>T (mean prediction error of 22%, P<0.001, mean CVC consistency of 7.40, P<0.037). For leukemia, a 3-loci model including RAD52-2259C>T, MnSOD-Ala9Val and CYP1A1-Ile462Val had a minimum prediction error of 31% (P<0.001) and a maximum CVC of 4.40 (P=0.086). The MDR method seems promising, because it provides a limited number of statistically stable interactions; however, the biological interpretation remains to be understood.
Carcinogenesis 2007 Feb
PMID:Multi-factor dimensionality reduction applied to a large prospective investigation on gene-gene and gene-environment interactions. 1695 9

Germline mutations in the tumour suppressor genes breast cancer antigen gene (BRCA)1 and BRCA2 have been proven to portend a drastically increased lifetime risk of breast and ovarian cancers in the individuals who carry them. A number of studies have shown that the third most common cancer associated with these mutations is pancreatic cancer. BRCA1/2 mutations are characterised by "allelic" or "phenotypic" heterogeneity, in that they demonstrate differing cancer expressivity between and within pedigrees that segregate their mutations. If the same mutation is present in all our cells, why do some families with a given mutation display predominantly breast cancer? Why do other lineages show a preponderance of ovarian cancer? And why would some families have members who develop mostly or exclusively pancreatic cancer--a cancer that occurs more commonly in men and that lacks consistent evidence for a hormonal basis to its aetiology--which is clearly the case for breast and ovarian cancer? The answer is that other modifying genetic and environmental factors must interact to preferentially incite carcinogenesis in one organ over another. We are just beginning to elucidate what these factors are.
 ...
PMID:Role of BRCA1 and BRCA2 mutations in pancreatic cancer. 1697 16

A single nucleotide polymorphism (SNP309T>G) in the intronic promoter of MDM2 was recently found to accelerate carcinogenesis in early-onset cancer cases. This cancer acceleration presumably was due to increased SP1 binding, resulting in enhanced MDM2 transcriptional activation by estrogens. We evaluated MDM2 SNP309 in 343 familial breast cancer cases with known mutation status for CHEK2 1100delC, BRCA1 and BRCA2. Cancer acceleration was indeed observed in early-onset familial breast cancer cases (diagnosed <or= 51 years), with 16% of cases carrying the MDM2 SNP309 GG genotype as compared to 4% of late-onset cases (P = 0.029). The cancer acceleration was even more pronounced in the non-mutant familial breast cancer cases, with 17% of early-onset cases carrying MDM2 SNP309 GG as compared to 2% of late-onset cases (n = 214; P = 0.015). There was no evidence for an influence of estrogen signaling in the cancer acceleration by MDM2 SNP309, as there were no differences in the prevalence of MDM2 SNP309 GG among CHEK2 1100delC and BRCA2 mutant cases (with 90% ER-positive cancers) or BRCA1 mutant cases (10% ER-positive cancers). Nor did we observe differences in MDM2 SNP309 frequencies among 75 familial breast cancer cases of our cohort with known ER status. Overall, our data suggest that MDM2 SNP309 accelerates familial breast carcinogenesis, but that this acceleration is not influenced by estrogen signaling.
 ...
PMID:MDM2 SNP309 accelerates familial breast carcinogenesis independently of estrogen signaling. 1708 Mar 8

DNA copy number changes represent molecular fingerprints of solid tumors and are as such relevant for better understanding of tumor development and progression. In this study, we applied genome-wide array comparative genomic hybridization (aCGH) to identify gene-specific DNA copy number changes in chromosomal (CIN)- and microsatellite (MIN)-unstable sporadic colorectal cancers (sCRC). Genomic DNA was extracted from microdissected, matching normal colorectal epithelium and invasive tumor cells of formalin-fixed and paraffin-embedded tissues of 22 cases with colorectal cancer (CIN = 11, MIN = 11). DNA copy number changes were determined by aCGH for 287 target sequences in tumor cell DNAs, using pooled normal DNAs as reference. aCGH data of tumor cell DNAs was confirmed by fluorescence in situ hybridization (FISH) for three genes on serial tissues as those used for aCGH. aCGH revealed DNA copy number changes previously described by metaphase CGH (gains 7, 8q, 13q, and 20q; losses 8p, 15q, 18q, and 17p). However, chromosomal regions 20q, 13q, 7, and 17p were preferentially altered in CIN-type tumors and included DNA amplifications of eight genes on chromosome 20q (TOP1, AIB1, MYBL2, CAS, PTPN1, STK15, ZNF217, and CYP24), two genes on chromosome 13q (BRCA2 and D13S25), and three genes on chromosome 7 (IL6, CYLN2, and MET) as well as DNA deletions of two genes on chromosome 17p (HIC1 and LLGL1). Finally, additional CIN-tumor-associated DNA amplifications were identified for EXT1 (8q24.11) and MYC (8q24.12) as well as DNA deletions for MAP2K5 (15q23) and LAMA3 (18q11.2). In contrast, distinct MIN-tumor-associated DNA amplifications were detected for E2F5 (8p22-q21.3), GARP (11q13.5-q14), ATM (11q22.3), KAL (Xp22.3), and XIST (Xq13.2) as well as DNA deletions for RAF1 (3p25), DCC (18q21.3), and KEN (21q tel). aCGH revealed distinct DNA copy number changes of oncogenes and tumor suppressor genes in CIN- and MIN-type sporadic colorectal carcinomas. The identified candidate genes are likely to have distinct functional roles in the carcinogenesis and progression of CIN- and MIN-type sporadic CRCs and may be involved in the differential response of CIN- and MIN-type tumor cells to (adjuvant) therapy, such as 5-fluorouracil.
 ...
PMID:Array CGH identifies distinct DNA copy number profiles of oncogenes and tumor suppressor genes in chromosomal- and microsatellite-unstable sporadic colorectal carcinomas. 1714 21

Mutations in breast and ovarian cancer susceptibility genes BRCA1 and BRCA2 predispose women to a high risk of these cancers. Here, we show that lymphoblasts of women with BRCA1 mutations who had been diagnosed with breast cancer are deficient in the repair of some products of oxidative DNA damage, namely, 8-hydroxy-2'-deoxyguanosine and 8,5'-cyclopurine-2'-deoxynucleosides. Cultured lymphoblasts from 10 individuals with BRCA1 mutations and those from 5 control individuals were exposed to 5 Gy of ionizing radiation to induce oxidative DNA damage and then allowed to repair this damage. DNA samples isolated from these cells were analyzed by liquid chromatography/mass spectrometry and gas chromatography/mass spectrometry to measure 8-hydroxy-2'-deoxyguanosine, (5'-S)-8,5'-cyclo-2'-deoxyadenosine, (5'-R)-8,5'-cyclo-2'-deoxyguanosine, and (5'-S)-8,5'-cyclo-2'-deoxyguanosine. After irradiation and a subsequent period of repair, no significant accumulation of these lesions was observed in the DNA from control cells. In contrast, cells with BRCA1 mutations accumulated statistically significant levels of these lesions in their DNA, providing evidence of a deficiency in DNA repair. In addition, a commonly used breast tumor cell line exhibited the same effect when compared to a relevant control cell line. The data suggest that BRCA1 plays a role in cellular repair of oxidatively induced DNA lesions. The failure of cells with BRCA1 mutations to repair 8,5'-cyclopurine-2'-deoxynucleosides indicates the involvement of BRCA1 in nucleotide-excision repair of oxidative DNA damage. This work suggest that accumulation of these lesions may lead to a high rate of mutations and to deleterious changes in gene expression, increasing breast cancer risk and contributing to breast carcinogenesis.
 ...
PMID:Lymphoblasts of women with BRCA1 mutations are deficient in cellular repair of 8,5'-Cyclopurine-2'-deoxynucleosides and 8-hydroxy-2'-deoxyguanosine. 1728 54

Analysis of germline p53 mutations in breast cancer reveals that the Li-Fraumeni and Li-Fraumeni-like syndromes are mostly related to the loss of initiation codon 133 of regulatory TP53 isoforms (Delta133p53). In eight codons of exons 5-8 (including 133), mutations are frequent in Li-Fraumeni-related, but scarce in sporadic breast cancer, while in six more codons they are frequent both in familial and sporadic breast cancers. At the proximity of these codons, we observed in somatic mutation databases, 16 codons (minihotspots mostly in exons 7, 8) which undergo frequent G:C > A:T transitions (non-CpG) in all sporadic cancers. In addition, in sporadic breast cancer we observed 35 adjacent codons in which the following types of mutation are observed: frequent G:C > A:T transitions at CCs/GGs, frequent silent mutations in exons 5,6 and suppressed nonsense mutations (5 codons, few records). Non-CpG G:C > A:T transitions in the 35 codons are rare in familial cancers (p53, BRCA1, or BRCA2-related), but frequent in sporadic cancers in organs where Li-Fraumeni-related carcinogenesis is common e.g. adrenal cortex, soft tissues. These data are in support of the following tissue-specific processes: in sporadic breast cancer (sarcomas etc.), loss of methylation sites (in 35 codons mostly next to codon 133), might lead to loss of silencing of TP53 isoforms which are suppressed in these tissues. On the contrary, "spreading" of cytosine methylation (asymmetric) in a G:C-rich region next to common hotspots (codons 238-252 in minihotspots) and mutagenesis probably destabilizes all tissues. Frequent C > T activation at non-CpG is also observed in prostate sporadic cancer, which similarly to breast, undergoes age-related crisis. The above data reveal that tissue-specific epigenetic regulatory mechanisms might be involved in p53 instability.
 ...
PMID:G:C > A:T mutations and potential epigenetic regulation of p53 in breast cancer. 1750 80

High penetrance genes such as BRCA1 or BRCA2 account for only a small proportion of familial breast cancer in Chinese population. Estrogen has been proposed to participate in the proliferation and carcinogenesis of breast cancer. To investigate the association between genetic polymorphisms in genes encoding estrogen metabolizing, estrogen biosynthesizing enzyme and estrogen receptor and the breast cancer risk in BRCA1/BRCA2 negative Shanghai women, we conducted a case-control study including 114 cases with early-onset breast cancer or affected relatives and 121 healthy controls. The genotypes of estrogen receptor alpha (ERalpha), aromatase (CYP19), and catechol-O-methyltransferase (COMT) genes were analyzed by direct DNA-sequencing. Compared with H/H genotype of COMT Val158Met, COMT Val158Met L/L genotype was associated with a nonsignificantly elevated risk of breast cancer (OR: 3.72; 95% CI: 0.99-13.96, P=0.051). There was no statistically significant difference in genotype frequency of the ERalpha PvuII, ERalpha XbaI and CYP19 Arg264Cys polymorphism between controls and cases. When stratified by menopausal status, COMT Val158Met L/L (OR: 11.94; 95% CI: 1.48-96.03, P=0.02) and ERalpha PvuII P/p genotypes (OR: 2.67; 95% CI: 1.01-7.05, P=0.048) were associated with a significantly elevated risk of breast cancer in premenopausal women, and there was a association between ERalpha XbaI x/x genotype and the nonsignificantly increased risk of breast cancer in premenopausal women (OR: 6.88; 95% CI: 0.80-59.15, P=0.079). The multigenic analysis showed maybe these high risk genotypes had combined effect on breast cancer risk. Our findings suggest that polymorphism of genes involving estrogen-metabolizing pathway, estrogen- biosynthesizing pathway and estrogen receptor pathway may play an important role in the etiology of BRCA1/2 negative breast cancer with hereditary predisposing factors.
 ...
PMID:A multigenic study on breast cancer risk associated with genetic polymorphisms of ER Alpha, COMT and CYP19 gene in BRCA1/BRCA2 negative Shanghai women with early onset breast cancer or affected relatives. 1756 79


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>