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

BACKGROUND: Syk (Splenic Tyrosine Kinase) is an intracellular receptor protein kinase involved in cell proliferation, differentiation and phagocytosis. It has been studied in T and B lymphocytes, NK cells and platelets. The strong expression of Syk in mammary gland prompted research into its potential role in mammary carcinogenesis. There have been very few studies about its role in breast cancer with conflicting results. This study aims to investigate the hypothesis that Syk expression is down-regulated in breast cancer compared with ANCT and the association between its expression and clinicopathological parameters. MATERIALS AND METHODS: mRNA was extracted from 48 breast cancer specimens. Relative Syk to ribosomal RNA expression was determined by RT-PCR and Taqman methodology. Mann-Whitney U test was used to examine the association between Syk expression in cancer and ANCT. Spearman's rank correlation test was used to examine the association between Syk expression in tumours and patients' age, tumour size, tumour grade, estrogen and progesterone receptor status, lymph node metastasis, vascular invasion and clinical outcome. RESULTS: The median for the relative value of Syk expression was 0.17 and 0.18 (range: 0.12 - 0.56 and 0.0 - 1.77) for tumours and ANCT respectively. There was no significant association between Syk expression in cancers and ANCT (p= 0.598) nor between Syk expression in tumours and patients' age, tumour size, tumour grade, estrogen and progesterone receptor status, lymph node metastasis, vascular invasion or prognosis. CONCLUSION: This study shows that Syk mRNA expression does not seem to vary between breast tumours and ANCT. Furthermore, we observed no significant association between Syk expression and clinicopathological parameters.
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PMID:SYK expression in human breast cancer. 1584 33

Overexpression of human epidermal growth factor receptor 2 (HER-2/neu) characterizes a molecular subtype of breast cancer associated with poor clinical outcome. Preventive strategies for HER-2/neu-positive breast cancer, which is often estrogen and progesterone receptor negative, remain undefined. Activators of peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear hormone receptor also expressed in breast cancer, hold potential as cancer prevention agents. PPARgamma ligands include specific fatty acids and synthetic compounds, such as the thiazolidinediones, which appear to inhibit cell proliferation and tumorigenesis. We hypothesized that a thiazolidinedione, rosiglitazone, may serve as a chemopreventive agent for HER-2/neu-associated mammary carcinogenesis, but that efficacy may be influenced by dietary fat content. We studied the effects of diets enriched with corn or fish oil (25% of energy) with and without rosiglitazone (12 g/kg) in a 2 x 2 factorial design on mammary tumorigenesis in murine mammary tumor virus (MMTV)-HER-2/neu transgenic mice. Despite in vitro evidence of antiproliferative effects in an MMTV-HER-2/neu tumor cell line, rosiglitazone did not affect mammary carcinogenesis in vivo. Interestingly, fish oil-based diets markedly suppressed breast tumor incidence (57% of mice vs. 87% of corn oil-fed mice, P = 0.0001) as well as tumor multiplicity (P = 0.001) and mammary gland dysplasia (P = 0.001). These findings demonstrate a potent preventive effect of (n-3) PUFA on HER-2/neu-mediated mammary carcinogenesis, without interaction with a synthetic PPARgamma activator. Further studies focusing on the mechanisms by which (n-3) fatty acids suppress HER-2/neu signaling pathways involved in the pathogenesis of breast cancer are warranted.
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PMID:Dietary (n-3) polyunsaturated fatty acids inhibit HER-2/neu-induced breast cancer in mice independently of the PPARgamma ligand rosiglitazone. 1586 69

The progesterone receptor (PR) plays roles in normal mammary development and breast cancer formation, where it may exert both stimulatory and inhibitory actions. Previously, the breast cancer susceptibility gene product BRCA1 was found to interact with and inhibit the transcriptional activity of estrogen receptor-alpha. In this study, we found that exogenous wild-type BRCA1 inhibited the activity of the PR in transient transfection assays utilizing a mouse mammary tumor virus-Luc reporter. Wild-type BRCA1 inhibited the activity of endogenous PR in human breast cancer cells (T47D and MCF-7) and inhibited the activity of exogenous PR-A, PR-B, and [PR-A plus PR-B] isoforms. On the other hand, knockdown of endogenous BRCA1 using small interfering RNA enhanced the progesterone-stimulated activity of the PR by about 4-fold. We documented an in vivo association of the endogenous BRCA1 with PR isoforms A and B and a direct in vitro interaction between BRCA1 and PR, which was partially mapped. Whereas down-regulation of the coactivator p300 contributes to the BRCA1-mediated repression of estrogen receptor-alpha, this mechanism does not contribute to inhibition of PR activity, because exogenous p300 did not rescue the BRCA1 repression of PR activity. The BRCA1-PR interaction has functional consequences. Thus, we showed that BRCA1 inhibits the expression of various endogenous progesterone-responsive genes and inhibits progesterone-stimulated proliferation of T47D cells. Finally, exogenous progesterone caused an exaggerated proliferative response in the mammary glands of mice harboring a mammary-targeted conditional deletion of the full-length isoform of Brca1. These findings suggest that BRCA1 regulates the activity of progesterone, a major hormone of pregnancy that may also participate in mammary carcinogenesis.
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PMID:The breast cancer susceptibility gene BRCA1 regulates progesterone receptor signaling in mammary epithelial cells. 1610 39

The evaluation of expression levels of the estrogen receptor (ER) and progesterone receptor (PR) in endometrial cancer is a very common procedure in modern practice. However, the significance of such tests remains controversial, and the evaluation of the status of steroid receptors seems to be a more thoroughly justified practice. The present study was carried out with 145 endometrial cancer patients, all of whom had undergone operations at the Seoul National University Hospital, from 1993 to 2002. Paraffin-embedded tissue blocks were sectioned and immunostained with monoclonal anti-ER and anti-PR antibodies. Clinicopathological variables were also analyzed, with 10% cutoff values for ER and PR positivity. A multivariate Cox regression analysis was performed in order to estimate the influences of several clinicopathological and immunohistochemical covariates on patient survival. Forty seven specimens (32.4%) stained as ER positive, and 110 (75.9%) stained as PR-positive. Patients with PR-positive tumor tended to be both younger and more obese than patients with PR-negative tumors (P=0.020, 0.016). Well-differentiated tumors were found to be positive for ER or PR more frequently (P=0.015, <0.001). ER or PR-positive tumors exhibited significantly less myometrial invasion (P=0.042, 0.002). However, multivariate Cox regression analyses revealed that the expressions of ER and PR were not significantly associated with patient survival, and only advanced FIGO stage constituted an independent prognostic factor. Our results suggested that the evaluation of steroid receptors might prove helpful prior to surgery. Low ER and high PR values suggest that racial differences and/or sequential loss of receptors during carcinogenesis might be involved in the expression of steroid receptors in cases of endometrial cancer.
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PMID:Steroid receptor expressions in endometrial cancer: clinical significance and epidemiological implication. 1616 61

Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, is very closely associated with telomerase activity. Telomerase has been implicated in cellular immortalization and carcinogenesis. In situ detection of hTERT will aid in determining the localization of telomerase-positive cells. The aim of this study was to detect expression of hTERT mRNA, hTERT protein, estrogen receptor (ER) and progesterone receptor (PR) in paraffin-embedded breast tissue samples and to investigate the relationship between hTERT expression and various clinicopathological parameters in breast tumorigenesis. We used in situ hybridization (ISH) to examine hTERT gene expression, and immunohistochemistry (IHC) to examine expression of hTERT protein, ER and PR, in breast tissues including 64 adenocarcinomas, 2 phyllode tumors and their adjacent normal breast tissues. hTERT gene expression was detected by ISH in 56 (88%) carcinomas, but in neither of the 2 phyllode tumors. hTERT protein expression was detected by IHC in 52 (81%) carcinomas, but in neither of the 2 phyllode tumors. Moreover, ER and PR were expressed in 42 (66%) and 42 (66%) carcinomas, respectively, and in neither of the 2 phyllode tumors. In 4 cases of breast carcinoma that strongly expressed hTERT gene and protein before treatment, neo-adjuvant chemotherapy led to disappearance of gene and protein expression in all cases. There was a strong correlation between detection of hTERT gene expression by ISH and of hTERT protein by ICH in tissue specimens from breast tumors. These results suggest that detection of hTERT protein by ICH can be used to distinguish breast cancers as a potential diagnostic and therapeutic marker.
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PMID:Expression of human telomerase reverse transcriptase gene and protein, and of estrogen and progesterone receptors, in breast tumors: preliminary data from neo-adjuvant chemotherapy. 1621 Dec 20

Excessive oxidative stress may induce and promote breast carcinogenesis. Manganese superoxide dismutase (MnSOD) is critical to management of oxidative stress by catalyzing the formation of hydrogen peroxide from two superoxide anions. To examine the relationship between MnSOD Val-9Ala polymorphism, breast cancer and potential modifiers, we analyzed data from a large population-based case-control study. Study participants completed an in-home interviewer-administered questionnaire, and self-completed a Block food frequency questionnaire. Age-adjusted unconditional logistic models included 1034 cases and 1084 controls. As compared with Val/Val genotype, we found no association between MnSOD Ala/Val (OR = 0.98, 95% CI: 0.79-1.21) and Ala/Ala (OR = 1.00, 95% CI: 0.79-1.28) genotypes and breast cancer. Results did not differ by menopausal status, stage of tumor, or estrogen and progesterone receptor status. No discernable patterns of interaction were found between this MnSOD variant and anti-oxidative exposures, including fruit and vegetable intake or NSAID use, or pro-oxidant exposures, including smoking and alcohol. This study provides little evidence that variation in Val-9Ala polymorphism of MnSOD alone or through substantial interaction with key exposures believed to be pro- or anti-oxidant properties influences breast cancer risk.
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PMID:MnSOD Val-9Ala genotype, pro- and anti-oxidant environmental modifiers, and breast cancer among women on Long Island, New York. 1621 73

Evidence that the insulin pathway may be involved in breast carcinogenesis has increased the interest in dietary factors that influence insulin secretion and resistance. We investigated dietary carbohydrate, fibre, glycaemic index (GI) and glycaemic load (GL) in a prospective study of 324 breast cancers diagnosed in 12,273 post-menopausal women. Although an increase of 1 standard deviation in carbohydrate was marginally associated with risk of breast cancer, relative risk (RR) 1.31 (95% CI, 0.98, 1.75), there were no significant associations with fibre, 1.08 (0.92, 1.26), GI, 0.98 (0.88, 1.10) or GL, 1.19 (0.93, 1.52) or with carbohydrate foods (bread, rice, pasta). The RR for carbohydrate and localized disease was elevated, 1.40 (1.02, 1.92), but like those for fibre, GI and GL did not differ significantly between localized and non-localized disease. RRs for grade I, but not grade II or III, tumours were elevated for fibre, 1.38 (1.08, 1.75), carbohydrate, 1.56 (1.08, 2.25) and GL, 1.41 (1.01, 1.98) but not for GI, 0.84 (0.65, 1.09). The RRs for fibre and oestrogen receptor (ER) positive (+) and progesterone receptor (PR) positive (+) tumours, 1.36 (1.10, 1.67), differed significantly from those for ER positive (+) and PR negative (-) tumours, 1.01 (0.61, 1.69) and ER-/PR- tumours, 0.65 (0.43, 0.99), p = 0.005. Our data do not support a strong role for GI and GL in breast carcinogenesis but suggest that increased intake of fibre and carbohydrate may be associated with the diagnosis of cancers of more favourable prognosis.
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PMID:Dietary carbohydrate, fibre, glycaemic index, glycaemic load and the risk of postmenopausal breast cancer. 1621 55

A common feature of human breast oncogenesis is cell cycle deregulation. The expression of cyclins D1 and D3 was examined during estradiol-17beta (E(2))-induced mammary tumorigenesis in female August Copenhagen Irish (ACI) rats. Low serum E(2) levels ( approximately 60-120 pg/ml) were sufficient to induce mammary gland tumors (MGTs) that remarkably resemble human ductal breast cancer (BC) at the histopathologic and molecular levels. Western blot analysis of the E(2)-induced MGTs revealed a marked rise in cyclins D1 (24-fold), D3 (9-fold) and cdk4 (3-fold) expression compared with age-matched untreated controls. Small focal dysplasias with large, pale staining nuclei were commonly seen at 3-3.6 months, large focal dysplasias, including atypical ductal hyperplasia at 3.6-4.3 months, ductal carcinoma in-situ (DCISs) at 4.3-5.0 months, and 100% incidence of invasive ductal BC/frank tumors at 5-6 months were detected after E(2) treatment. Immunohistochemical analysis of serial sections of focal dysplasias, DCISs and invasive ductal carcinomas showed overexpression of cyclins D1, D3, estrogen receptor-alpha (ERalpha) and progesterone receptor (PR). However, cyclin D3 expression, unlike D1, was confined essentially to early pre-malignant lesions (focal dysplasias and DCISs) and primary MGTs with <1-5% of resting and normal hyperplastic breast cells staining positive. The kinase activity for cyclins D1 and D3, using retinoblastoma (Rb) as a substrate, in E(2)-induced MGTs and their binding to cdk4 was significantly elevated. Semi-quantitative reverse transcriptase PCR analysis of the E(2)-induced MGTs exhibited increased expression of cyclins D1 (2.9-fold) and D3 (1.4-fold) mRNA, indicating that their elevated protein expression was due in part to an increase in mRNA transcription. However, when analyzed by quantitative real-time Q-PCR, these genes were not amplified. These data indicate that in female ACI rat mammary glands, E(2)-induced pre-malignant lesions differentially and selectively express cyclins D1 and D3, thus contributing to a distinct growth advantage of these pre-neoplasias relative to E(2)-elicited normal hyperplasia.
Carcinogenesis 2006 Mar
PMID:Overexpression of cyclins D1 and D3 during estrogen-induced breast oncogenesis in female ACI rats. 1631 Dec 45

p53-binding protein 1 (P53BP1), a central transducer of DNA-damage signals to p53, is required for both intra-S-phase and G2-M checkpoints, suggesting that these two proteins may work together in the p53-mediated transcriptional activation and DNA damage-repair signaling pathways. Because the p53-binding region of 53BP1 maps to the C-terminal BRCT domains, which are homologous to those found in the breast cancer protein BRCA1, we hypothesized that genetic variation in P53BP1 and p53 may contribute to breast cancer predisposition. To test this hypothesis, we simultaneously genotyped single nucleotide polymorphisms of T-885G, Glu353Asp, and Gln1136Lys in P53BP1 and Arg72Pro in p53 in a case-control study of 404 breast cancer cases and 472 cancer-free controls. We found that the P53BP1 variant genotypes (alleles) of T-885G and Gln1136Lys were associated with a significantly increased risk of breast cancer among p53 Pro/Pro carriers (OR=2.36, 95% CI 1.16-4.83 for -885TG/GG; OR=2.24, 95% CI 1.15-4.37 for 1136Gln/Lys+Lys/Lys and OR=2.82, 95% CI 1.15-6.94 for >4 variant alleles of these 3 loci). In addition, the variant genotypes of above 3 loci of P53BP1 were significantly associated with elevated risk of progesterone receptor (PR) negative breast cancer, and the T-885G and Gln1136Lys with estrogen receptor (ER) negative breast cancer. Furthermore, we found a significant gene-gene interaction between P53BP1 Gln1136Lys and p53 Arg72Pro variants in relation to breast cancer, and the OR of interaction for the presence of both P53BP1 1136Gln/Lys+Lys/Lys and p53 72Arg/Pro+Pro/Pro genotypes was 1.93 (95% CI 1.06-3.52) (P=0.031 for interaction). These findings indicate that the SNPs in P53BP1 and p53 jointly contribute to breast cancer risk, particularly ER (-) or PR (-) breast cancer, and the p53 Arg72Pro polymorphism may serve as a risk modifier. Further functional studies are needed to confirm our findings.
Carcinogenesis 2006 Apr
PMID:Joint effects of single nucleotide polymorphisms in P53BP1 and p53 on breast cancer risk in a Chinese population. 1631 99

To explore the molecular mechanisms for the similarities between inherited and noninherited forms of breast cancer, we tested the hypothesis that inactivation of BRCA1 by promoter hypermethylation is associated with reduced gene copy number and chromosome 17 aneusomy as observed in tumors from BRCA1 mutation carriers. Using a combination of methylation-specific PCR analysis and fluorescence in situ hybridization, we observed varying degrees of promoter methylation in 39 of 131 (29.8%) primary tumors. Despite significant tumor heterogeneity, mean copy numbers of BRCA1 and CEP17 per cell were lower in methylated cases compared with unmethylated cases [1.78 versus 2.30 (P = 0.001) and 1.85 versus 2.29 (P = 0.005), respectively]. Methylation was more frequently observed in younger women (P = 0.05) with high-grade (P = 0.001), estrogen receptor-negative (P = 0.04), and progesterone receptor-negative (P = 0.01) tumors. Moreover, methylation was associated with reduced or absent BRCA1 transcripts, which was reversible in the heavily BRCA1-methylated cell line UACC3199 following treatment with 5-aza-2'-deoxycytidine and trichostatin A. We identified five CpGs at positions -533, -355, -173, -21, and +44 as critical in the reexpression of BRCA1. We conclude that BRCA1 methylation contributes to a subset of sporadic breast cancers with the resulting molecular and clinicopathologic phenotype similar to that of hereditary BRCA1-associated breast cancers. Our data support a model of carcinogenesis in which BRCA1 promoter methylation may serve as a "first hit," much like an inherited germ line mutation, and promote tumor progression down a restricted set of molecular pathways.
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PMID:BRCA1 promoter methylation in sporadic breast cancer is associated with reduced BRCA1 copy number and chromosome 17 aneusomy. 1632 13


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