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E Evron

Publications and source records attributed to E Evron.

At least 19 recordsLinked to original sources
PubMed2001

CpG methylation as a basis for breast tumor-specific loss of NES1/kallikrein 10 expression.

The normal epithelial cell-specific-1 (NES1)/kallikrein 10 gene is expressed in normal mammary epithelial cells, but its expression is dramatically decreased in breast cancer cell lines. Now, we have cloned and characterized the active promoter region of NES1. Using a luciferase reporter system, we demonstrate that most tumor cell lines are able to support full or partial transcription from the NES1 promoter, suggesting a role for promoter-independent cis-acting mechanisms of loss of NES1 expression. We show that hypermethylation of the NES1 gene represents one such mechanism. Using methylation-specific PCR and sequence analysis of sodium bisulfite-treated genomic DNA, we demonstrate a strong correlation between exon 3 hypermethylation and loss of NES1 mRNA expression in a panel of breast cancer cell lines and in primary tumors. Treatment of NES1-nonexpressing cells with a demethylating agent led to reexpression of NES1, suggesting an important role of hypermethylation in the loss of NES1 expression. We suggest that hypermethylation is responsible for tumor-specific loss of NES1 gene expression. Our results also suggest that hypermethylation of the NES1 gene may serve as a potential marker for breast cancer.

Antimetabolites, Antineoplastic↗
PubMed2001

Hypermethylation of 14-3-3 sigma (stratifin) is an early event in breast cancer.

We have identified 14-3-3 sigma (sigma) as a gene whose expression is lost in breast carcinomas, primarily by methylation-mediated silencing. In this report, we investigated the timing of loss of sigma gene expression during breast tumorigenesis in vivo. We analysed the methylation status of sigma in breast cancer precursor lesions using microdissection for selective tissue sampling. We found hypermethylation of sigma in 24 of 25 carcinomas (96%), 15 of 18 (83%) of ductal carcinoma in situ, and three of eight (38%) of atypical hyperplasias. None of the five hyperplasias without atypia showed sigma-hypermethylation. Unexpectedly, patients with breast cancer showed sigma hypermethylation in adjacent histologically normal breast epithelium, while this was never observed in individuals without evidence of breast cancer. Also, samples of periductal stromal breast tissue were consistently hypermethylated, underscoring the importance of selective tissue sampling for accurate assessment of 14-3-3-sigma methylation in breast epithelium. These results suggest that hypermethylation of 14-3-3-sigma occurs at an early stage in the progression to invasive breast cancer, and may occur in apparently normal epithelium adjacent to breast cancer. These results provide evidence that loss of expression of sigma is an early event in neoplastic transformation.

14-3-3 Proteins↗
PubMed2001

Detection of breast cancer cells in ductal lavage fluid by methylation-specific PCR.

If detected early, breast cancer is curable. We tested cells collected from the breast ducts by methylation-specific PCR (MSP). Methylated alleles of Cyclin D2, RAR-beta, and Twist genes were frequently detected in fluid from mammary ducts containing endoscopically visualised carcinomas (17 cases of 20), and ductal carcinoma in situ (two of seven), but rarely in ductal lavage fluid from healthy ducts (five of 45). Two of the women with healthy mammograms whose ductal lavage fluid contained methylated markers and cytologically abnormal cells were subsequently diagnosed with breast cancer. Carrying out MSP in these fluid samples may provide a sensitive and powerful addition to mammographic screening for early detection of breast cancer.

Breast↗
PubMed2001

Loss of cyclin D2 expression in the majority of breast cancers is associated with promoter hypermethylation.

Cyclin D2 is a member of the D-type cyclins, implicated in cell cycle regulation, differentiation, and malignant transformation. It was noted previously that cyclin D2 is not expressed in the majority of breast cancer cell lines, whereas abundant expression was detected in finite life span human mammary epithelial cells. By reverse transcription-PCR and Western blot analysis, we extended this finding to primary breast carcinomas and show that the majority of these tumors lack expression of cyclin D2 mRNA (18 of 24) and protein (10 of 13). In contrast, both luminal and myoepithelial subpopulations of normal breast tissues expressed cyclin D2. Hypermethylation of the CpG island in the promoter was detected by methylation-specific PCR in nearly half of the breast cancers (49 of 106) and was associated with silencing of cyclin D2 gene expression. Promoter hypermethylation was also detected in ductal carcinoma in situ, suggesting that loss of cyclin D2 expression is an early event in tumorigenesis. Our results suggest that loss of cyclin D2 expression is associated with the evolution of breast cancer.

Blotting, Western↗
PubMed2001

Wilms' tumor suppressor gene (WT1) is expressed in primary breast tumors despite tumor-specific promoter methylation.

We analyzed Wilms' tumor suppressor 1 (WT1) expression and its regulation by promoter methylation in a panel of normal breast epithelial samples and primary carcinomas. Contrary to previous reports, WT1 protein was strongly expressed in primary carcinomas (27 of 31 tumors) but not in normal breast epithelium (1 of 20 samples). Additionally, the WT1 promoter was methylated in 6 of 19 (32%) primary tumors, which nevertheless expressed WT1. The promoter is not methylated in normal epithelium. Thus, although tumor-specific methylation of WT1 is established in primary breast cancer at a low frequency, other transcriptional regulatory mechanisms appear to supercede its effects in these tumors. Our results demonstrate expression of WT1 in mammary neoplasia, and that WT1 may not have a tumor suppressor role in breast cancer.

Breast↗
PubMed2000

Compromised HOXA5 function can limit p53 expression in human breast tumours.

Expression of the p53 gene protects cells against malignant transformation. Whereas control of p53 degradation has been a subject of intense scrutiny, little is known about the factors that regulate p53 synthesis. Here we show that p53 messenger RNA levels are low in a large proportion of breast tumours. Seeking potential regulators of p53 transcription, we found consensus HOX binding sites in the p53 promoterS. Transient transfection of Hox/HOXA5 activated the p53 promoter. Expression of HOXA5 in epithelial cancer cells expressing wild-type p53, but not in isogenic variants lacking the p53 gene, led to apoptotic cell death. Moreover, breast cancer cell lines and patient tumours display a coordinate loss of p53 and HOXA5 mRNA and protein expression. The HOXA5 promoter region was methylated in 16 out of 20 p53-negative breast tumour specimens. We conclude that loss of expression of p53 in human breast cancer may be primarily due to lack of expression of HOXA5.

Animals↗
PubMed2000

High frequency of hypermethylation at the 14-3-3 sigma locus leads to gene silencing in breast cancer.

Expression of 14-3-3 final sigma (final sigma) is induced in response to DNA damage, and causes cells to arrest in G(2). By SAGE (serial analysis of gene expression) analysis, we identified final sigma as a gene whose expression is 7-fold lower in breast carcinoma cells than in normal breast epithelium. We verified this finding by Northern blot analysis. Remarkably, final sigma mRNA was undetectable in 45 of 48 primary breast carcinomas. Genetic alterations at final sigma such as loss of heterozygosity were rare (1/20 informative cases), and no mutations were detected (0/34). On the other hand, hypermethylation of CpG islands in the final sigma gene was detected in 91% (75/82) of breast tumors and was associated with lack of gene expression. Hypermethylation of final sigma is functionally important, because treatment of final sigma-non-expressing breast cancer cell lines with the drug 5-aza-2'-deoxycytidine resulted in demethylation of the gene and synthesis of final sigma mRNA. Breast cancer cells lacking final sigma expression showed increased number of chromosomal breaks and gaps when exposed to gamma-irradiation. Therefore, it is possible that loss of final sigma expression contributes to malignant transformation by impairing the G(2) cell cycle checkpoint function, thus allowing an accumulation of genetic defects. Hypermethylation and loss of final sigma expression are the most consistent molecular alterations in breast cancer identified so far.

14-3-3 Proteins↗
PubMed1999

Primary multifocal lymphoma of bone presenting as hypercalcemic crisis: report of a rare manifestation of extranodal lymphoma.

Primary non-Hodgkin's lymphoma of bone is uncommon and usually manifests clinically as localized bone pain. Here we report a woman who presented with hypercalcemic crisis and extensive investigation revealed a primary multifocal lymphoma of bone. The course of the disease was very aggressive and despite intensive supportive care and urgent chemotherapy the patient died within 1 month. Since her blood PTH and calcitriol levels were suppressed and her parathyroid-hormone-related peptide (PTHrp) was mildly elevated, we believe that release of cytokines combined with PTHrp, as well as extensive osteolytic lesions, were the causes of the hypercalcemia. This is an unusual presenting symptom of lymphomas and to the best of our knowledge severe symptomatic hypercalcemia and crisis has never been reported in primary lymphoma of bone before.

Aged↗
PubMed1998

Point mutation and homozygous deletion of PTEN/MMAC1 in primary bladder cancers.

A new tumor suppressor gene PTEN/MMAC1 was recently isolated at chromosome 10q23 and found to be inactivated by point mutation or homozygous deletion in glioma, prostate and breast cancer. PTEN/MMAC1 was also identified as the gene predisposing to Cowden disease, an autosomal dominant cancer predisposition syndrome associated with an increased risk of breast, skin and thyroid tumors and occasional cases of other cancers including bladder and renal cell carcinoma. We screened 345 urinary tract cancers by microsatellite analysis and found chromosome 10q to be deleted in 65 of 285 (23%) bladder and 15 of 60 (25%) renal cell cancers. We then screened the entire PTEN/MMAC1 coding region for mutation in 25 bladder and 15 renal cell primary tumors with deletion of chromosome 10q. Two somatic point mutations, a frameshift and a splicing variant, were found in the panel of bladder tumors while no mutation was observed in the renal cell carcinomas. To screen for homozygous deletion, we isolated two polymorphic microsatellite repeats from genomic BAC clones containing the PTEN/MMAC1 gene. Using these new informative markers, we identified apparent retention at the gene locus indicative of homozygous deletion of PTEN/MMAC1 in four of 65 bladder and 0 of 15 renal cell tumors with LOH through chromosome 10q. Identification of the second inactivation event in six bladder tumors with LOH of 10q implies that the PTEN/MMAC1 gene is occasionally involved in bladder tumorigenesis. However, the low frequency of biallelic inactivation suggests that either PTEN/MMAC1 is inactivated by other mechanisms or it is not the only target of chromosome 10q deletion in primary bladder and renal cell cancer.

Base Sequence↗
PubMed1998

Analysis of PTEN/MMAC1 alterations in aerodigestive tract tumors.

PTEN/MMAC1 is a candidate tumor suppressor gene recently identified at chromosomal band 10q23. It is mutated in sporadic brain, breast, and prostate cancer and in the germ line of patients with hereditary Cowden disease. We searched for genetic alterations of the PTEN/MMAC1 gene in 39 primary head and neck cancers (HNSCCs), 42 primary non-small cell lung cancers (NSCLCs), 80 pancreatic cancer xenografts, and 37 cell lines and xenografts from colon, lung, and gastric cancers. Microsatellite analysis revealed loss of heterozygosity at markers near the gene in 41% of primary HNSCCs, 50% of NSCLCs, and 39% of the pancreatic cancers. Three cases of HNSCCs displayed homozygous deletion involving the gene. We sequenced the entire coding region of the PTEN/MMAC1 gene in the remaining tumors displaying loss of heterozygosity and found one terminating mutation in a HNSCC sample. Thus, a second inactivation event was observed in 4 of 39 primary HNSCC cases. By use of a protein truncation assay, one terminating mutation was also identified in one of eight NSCLC cell lines. Our results suggest that PTEN/MMAC1 gene inactivation plays a role in the genesis of some tumor types.

Carcinoma, Non-Small-Cell Lung↗
PubMed1998

Somatic mutations of the PTEN tumor suppressor gene in sporadic follicular thyroid tumors.

The PTEN (MMAC1/TEP1) tumor suppressor gene was recently isolated and mapped to human chromosome band 10q23. Homozygous deletions and mutations of PTEN were observed in cell lines and sporadic cancers of the breast, kidney, and central nervous system. Germline mutations in PTEN were recently found in Cowden disease, an autosomal dominant inherited syndrome, previously mapped to chromosome bands 10q22-23. This disease is associated with a wide variety of malignancies and hamartomas of ectodermal, mesodermal, and endodermal origin. The most common neoplasms in Cowden disease patients arise in the breast, skin, and thyroid (follicular subtype). To determine the involvement of PTEN in sporadic follicular thyroid tumors, we first analyzed sporadic follicular adenomas and carcinomas for deletions of the PTEN gene. Loss of heterozygosity was found in 7/26 (27%) follicular carcinomas and 2/27 (7%) follicular adenomas, one of which was a small hemizygous deletion (approximately 3 cm). Sequence analysis of the entire PTEN coding region revealed two mutations in carcinomas with 10q loss. Our findings suggest that the PTEN tumor suppressor gene is occasionally inactivated in sporadic follicular thyroid tumors.

Adenocarcinoma, Follicular↗
PubMed1997

Idiopathic calcitriol-induced hypercalcemia. A new disease entity?

We describe 3 patients with a prolonged history of hypercalcemia. The patients did not take any vitamin supplements. All patients had low parathyroid hormone (PTH), high calcitriol (1,25(OH)2D3), and high angiotensin-converting enzyme (ACE) blood levels. There was no evidence of sarcoidosis of any other underlying disease in the results of an extensive workup. Treatment with prednisone resulted in normalization of calcium levels in all patients. They remained dependent on low-dose prednisone on a subsequent prolonged follow-up.

Calcitriol↗
PubMed1997

Normal polymorphism in the incomplete trinucleotide repeat of the arginine-rich protein gene.

The arginine-rich protein (ARP) gene was recently cloned and localized to human chromosome band 3p21. Recent reports have suggested that ARP is mutated in a high percentage of different human tumors. We amplified and sequenced the multiple arginine coding area of the ARP gene in primary head and neck, non-small cell lung, and renal cell cancers. We found a high frequency of genetic changes in this region, including a single base pair substitution and deletions of arginine repeats in primary tumors. However, these changes were always present in matched normal controls. Thus, the variations in the ARP trinucleotide repeat region represent normal polymorphisms rather than tumor-specific mutations.

Carcinoma, Non-Small-Cell Lung↗
PubMed1997

HCV hepatitis associated with anticardiolipin antibody and a cerebrovascular accident. Response to interferon therapy.

A 54-year-old man with chronic hepatitis C virus (HCV) developed quadrihemianopsia caused by lacunar brain infarction. Extensive evaluation revealed high titers of anticardiolipin antibodies (ACA). Following interferon treatment (6 x 10(6), three times a week for 2 months and 3 x 10(6) for another 7 months), liver transaminase levels decreased to normal, HCV RNA in blood was no longer detectable, concomitantly with the disappearance of the ACA. The patient remained clinically stable without evidence for either HCV activity (RNA) or ACA or further thromboembolic events.

Antibodies, Anticardiolipin↗
PubMed1997

[Budd-Chiari syndrome].

Budd Chiari syndrome is a rare disorder resulting from occlusion of hepatic venous drainage by hepatic vein thrombosis or by a membranous web in the inferior vena cava. In western countries the commonest causes are myeloproliferative disorders and hypercoagulable states. Presentation may be acute with rapid accumulation of ascites and hepatic failure, or subacute with symptoms developing over a few months. A chronic progressive form has also been described. On presentation there is usually abdominal pain, ascites, and hepatosplenomegaly; hepatic encephalopathy is found in about a third. Noninvasive, ultrasound-Doppler is recommended in diagnosis, and has a high correlation with hepatic venography. Liver biopsy is required for therapeutic decisions. Those with advanced hepatic failure or severe fibrosis on liver biopsy are referred for hepatic transplantation. When biopsy shows only hepatic congestion and inflammatory infiltrates, portosystemic shunting is recommended. We present a 61-year-old woman with ascites and hepatosplenomegaly that had developed over the courses of a few months. Budd-Chiari syndrome with chronic myelofibrosis and congenital protein C deficiency were diagnosed. Portosystemic shunt was performed but death from sepsis followed shortly.

Budd-Chiari Syndrome↗