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Loss of disabled-2 expression is an early event in esophageal squamous tumorigenesis.

ABSTRACT: AIM:Disabled-2 (DAB2) is a candidate tumor-suppressor gene identified in ovarian cancer that negatively influences mitogenic signal transduction of growth factors and blocks ras activity. In a recent study, we observed down-regulation of DAB2 transcripts in ESCCs using cDNA microarrays. In the present study, we aimed to determine the clinical significance of loss of DAB2 protein in esophageal tumorigenesis, hypothesizing that DAB2 promoter hypermethylation-mediated gene silencing may account for loss of the protein. METHODS:DAB2 expression was analyzed by immunohistochemistry in 50 primary esophageal squamous cell carcinomas (ESCCs), 30 distinct hyperplasia, 15 dysplasia and 10 non-malignant esophageal tissues. To determine whether promoter hypermethylation contributes to loss of DAB2 expression in ESCCs, methylation status of DAB2 promoter was analyzed in DAB2 immuno-negative tumors using methylation-specific PCR. RESULTS:Loss of DAB2 protein was observed in 5/30 (17%) hyperplasia, 10/15 (67%) dysplasia and 34/50 (68%) ESCCs. Significant loss of DAB2 protein was observed from esophageal normal mucosa to hyperplasia, dysplasia and invasive cancer (P(trend) < 0.001). Promoter hypermethylation of DAB2 was observed in 2 of 10 (20%) DAB2 immuno-negative ESCCs. CONCLUSION:Loss of DAB2 protein expression occurs in early pre-neoplastic stages of development of esophageal cancer and is sustained down the tumorigenic pathway. Infrequent DAB2 promoter methylation in ESCCs suggests that epigenetic gene silencing is only one of the mechanisms causing loss of DAB2 expression in ESCCs.

SUBMITTER: Anupam K

PROVIDER: S-EPMC4124415 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature

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Loss of disabled-2 expression is an early event in esophageal squamous tumorigenesis.

Anupam Kumar K Tusharkant Chatopadhyay C Gupta Siddhartha Datta SD Ranju Ralhan R

World journal of gastroenterology 20061001 37

<h4>Aim</h4>Disabled-2 (DAB2) is a candidate tumor-suppressor gene identified in ovarian cancer that negatively influences mitogenic signal transduction of growth factors and blocks ras activity. In a recent study, we observed down-regulation of DAB2 transcripts in ESCCs using cDNA microarrays. In the present study, we aimed to determine the clinical significance of loss of DAB2 protein in esophageal tumorigenesis, hypothesizing that DAB2 promoter hypermethylation-mediated gene silencing may acc ...[more]

PMID: 17009406

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Project description:p33(ING1b), a newly discovered candidate tumor suppressor gene and a nuclear protein, belongs to the inhibitor of growth gene family. Previous studies have shown that p33(ING1b) is involved in the restriction of cell growth and proliferation, apoptosis, tumor anchorage-independent growth, cellular senescence, maintenance of genomic stability and modulation of cell cycle checkpoints. Loss of nuclear p33(ING1b) has been observed in melanoma, seminoma, papillary thyroid carcinoma, oral squamous cell carcinoma, breast ductal cancer and acute lymphoblastic leukemia. Inactivation and/or decreased expression of p33(ING1b) have been reported in various types of cancer, including head and neck squamous cell, breast, lung, stomach, blood and brain malignancies. Since little is known about the clinicopathological significance of p33(ING1b) in esophageal squamous cell carcinoma (ESCC), this study aimed to investigate the association of p33(ING1b) expression with clinicopathological variables and particularly interesting new cysteine-histidine rich protein (PINCH) in patients with ESCC. p33(ING1b) expression was examined by immunohistochemistry in 20 normal esophageal mucosa and in 64 ESCC specimens. The results revealed that the positive expression of p33(ING1b) protein in normal squamous cells was localized in the nucleus alone and the positive rate was 95%, while in ESCCs, the positive expression was mainly in the cytoplasm, together with nuclear expression, and the positive rate was 36% (P<0.0001). Furthermore, the cases with lymph node metastasis showed a higher frequency of positive cytoplasmic expression than those without metastasis (P=0.001). The cytoplasmic expression of p33(ING1b) was positively related to PINCH expression (P<0.0001) in ESCC, and the cases positive for both proteins had a high lymph node metastasis rate (P=0.001). In conclusion, p33(ING1b) cellular compartmental shift from the nucleus to the cytoplasm may cause loss of normal cellular function and play a central role in the tumorigenesis and metastasis of ESCC.

Project description:Smoking and alcohol consumption are major risk factors for the development of esophageal squamous cell carcinoma (ESCC). Recent studies have demonstrated that smoking and alcohol consumption may be associated with altered DNA methylation in human cancer development. The aim of the present study was to evaluate methylation-modulated protein expression of tumor-related genes (TRGs) in the early stages of esophageal squamous neoplasia (ESN). ESN tissue samples (n=141) comprising 19 cases of low-grade intraepithelial neoplasia (LGIN), 70 of high-grade intraepithelial neoplasia/carcinoma in situ (HGIN/CIS) and 52 of invasive cancer, were endoscopically resected. The methylation-modulated protein expression of 5 TRGs [fragile histidine triad (FHIT), E-cadherin, MutL homolog 1 (MLH1) /MutS homolog 2 (MSH2) and cyclooxygenase-2 (COX-2)] as well as p53 was examined with immunohistochemistry, and their expression was compared with patient clinicopathological characteristics. Reduced or loss of FHIT, E-cadherin, MLH1/MSH2 and COX-2 expression was detected in 26.3 (5/19), 5.3 (1/19), 0 (0/19) and 63.2% (12/19) of LGIN cases, 61.4 (43/70), 18.6 (13/70), 7.1 (5/70) and 65.7% (46/70) of HGIN/CIS cases, and 78.8 (41/52), 50.0 (26/52), 11.5 (6/52) and 59.6% (31/52) of invasive cancer cases, respectively. Reduced or absent expression of FHIT and E-cadherin was significantly associated with neoplastic progression (FHIT, P=0.0007; E-cadherin, P=0.00014). The mean number of TRGs (FHIT, E-cadherin, MLH1/MSH2, and COX-2) that exhibited reduced or absent expression in LGIN, HGIN/CIS and invasive cancer specimens was 1.12±0.61, 1.66±0.93 and 2.09±0.96, respectively, demonstrating a significant stepwise increment from LGIN to HGIN/CIS and then to invasive cancer (P<0.05). p53 overexpression was frequently detected in ESN with head and neck carcinomas. However p53 overexpression was not significantly associated with ESN progression. An increase in the number of the 5 TRG proteins with reduced or loss of expression in the early stages of esophageal tumorigenesis was demonstrated, and their decreased expression was observed to be associated with tumor progression. Therefore, smoking and alcohol drinking may be associated with not only carcinogenesis but also the progression of ESN.

Dataset Information

Loss of disabled-2 expression is an early event in esophageal squamous tumorigenesis.

Publications

Loss of disabled-2 expression is an early event in esophageal squamous tumorigenesis.

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