CDH1 Gene Methylation Research Articles

Huddled and Preternatural- Atypical Lobular Hyperplasia

Atypical lobular hyperplasia manifests as a clonal proliferation of dis-cohesive epithelial cells emerging from terminal duct lobular units. Neoplasm appears reminiscent of lobular carcinoma in situ (LCIS) although cellular quantification is reduced. Characteristically, the incidentally discovered lesion is associated with dysfunction or decimation of E-cadherin. Additionally designated as lobular intraepithelial neoplastic 1 (LIN1), tumefaction exemplifies a female preponderance. Typically, adult subjects are implicated. Tumefaction is commonly encountered within the fifth decade although no age of disease emergence is exempt. Atypical lobular hyperplasia is detected within<1% of core needle biopsies adopted for evaluating BI-RADS 4 lesions [1,2]. Atypical lobular hyperplasia may incriminate bilateral breasts wherein specific lesion localization is absent. Tumefaction exhibits loss of chromosome 16qand deletion of CDH1 genes with loss of function of E-cadherin, a Tran’s membrane cell adhesion molecule. Alternatively, altered function of E-cadherin may occur. Exceptionally, various adhesion proteins are implicated wherein E-cadherin molecule appears stable [1,2]. Characteristically, atypical lobular hyperplasia is a diploid neoplasm. Tumefaction exhibits loss of heterozygosis (LOH) at chromosome 16q. A subset of neoplasms demonstrates methylation of CDH1 gene. Several tumefaction express loss of chromosome 22q and 16p, gain of chromosome 2p11.2, 5q32- 33.1 (CSF1R), 6q, 11q13 or 14q32.33.

The chromatin architectural regulator SND1 mediates metastasis in triple-negative breast cancer by promoting CDH1 gene methylation

BackgroundSND1 participates in tumorigenesis, tumour invasion and metastasis in different cancers. Previous studies have shown that SND1 can promote the invasion and migration of breast cancer cells. Triple-negative breast cancer (TNBC) is a specific breast cancer subtype with high metastatic potential and poor prognosis. However, the specific roles and mechanisms of SND1 in TNBC metastasis remain unaddressed.MethodsImmunostaining was used to detect the SND1 expression in tissue samples of 58 TNBC and 10 glioblastomas (GBM) as positive control. The correlation between SND1 expression and patient prognosis was assessed using the Kaplan–Meier estimator. The gene expression was evaluated by qRT-PCR, Western blot and immunofluorescence analyses. Gene Ontology analysis, ChIP, a dual-luciferase reporter assay, EMSA, and 3C analysis were applied to identify SND1-activated target genes. Bisulfite sequencing PCR and MeDIP were used to detect DNA methylation. We also used wound healing, Transwell and orthotopic implantation assays to investigate the function of SND1 in TNBC cell migration and invasion.ResultsThe data of immunohistochemistry manifested that SND1 is the overexpression in metastasized TNBC and an independent factor for TNBC prognosis. SND1 knockdown inhibited the migration and invasion of TNBC cells. We found that SND1 promotes the metastatic phenotype of TNBC cells by epigenetically altering chromatin conformational interactions, which in turn activates DNMT3A transcription. Then, DNMT3A attenuates CCND1 expression by inducing CCND1 gene methylation, leading to TNBC metastasis.ConclusionSND1 can promote the invasion and migration of TNBC cells by promoting DNMT3A expression and suppressing CDH1 activity. SND1 is a potential biomarker and a promising therapeutic target for TNBC.

CDH1 (E-cadherin) Gene Methylation in Human Breast Cancer: Critical Appraisal of a Long and Twisted Story.

Simple SummaryGenes can be inactivated by specific modifications of DNA bases, most often by adding a methyl group to the DNA base cytosine if it is followed by guanosine (CG methylation). This modification prevents gene expression and has been reported for many different genes in nearly all types of cancer. A prominent example is the gene CDH1, which encodes the cell-adhesion molecule E-cadherin. This is an important player in the spreading of tumor cells within the body (metastasis). Particularly in human breast cancer, many different research groups have studied the inactivation of the CDH1 gene via DNA methylation using various methods. Over the last 20 years, different, in part, even contradicting results have been published for the CDH1 gene in breast cancer. This review summarizes the most important publications and explains the bewildering heterogeneity of results through careful analysis of the methods which have been used.Epigenetic inactivation of a tumor suppressor gene by aberrant DNA methylation is a well-established defect in human tumor cells, complementing genetic inactivation by mutation (germline or somatic). In human breast cancer, aberrant gene methylation has diagnostic, prognostic, and predictive potential. A prominent example is the hypermethylation of the CDH1 gene, encoding the adhesion protein E-Cadherin (“epithelial cadherin”). In numerous publications, it is reported as frequently affected by gene methylation in human breast cancer. However, over more than two decades of research, contradictory results concerning CDH1 gene methylation in human breast cancer accumulated. Therefore, we review the available evidence for and against the role of DNA methylation of the CDH1 gene in human breast cancer and discuss in detail the methodological reasons for conflicting results, which are of general importance for the analysis of aberrant DNA methylation in human cancer specimens. Since the loss of E-cadherin protein expression is a hallmark of invasive lobular breast cancer (ILBC), special attention is paid to CDH1 gene methylation as a potential mechanism for loss of expression in this special subtype of human breast cancer. Proper understanding of the methodological basis is of utmost importance for the correct interpretation of results supposed to demonstrate the presence and clinical relevance of aberrant DNA methylation in cancer specimens.

The effect of sodium butyrate and cisplatin on expression of EMT markers.

Histone modifications play a key role in the epigenetic regulation of gene transcription in cancer cells. Histone acetylations are regulated by two classes of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDACs are increased in ovarian carcinomas and they are involved in carcinogenesis and resistance to chemotherapeutic agents. In our study we investigated anticancer effect of HDAC inhibitor sodium butyrate (NaBu) on cisplatin-sensitive and cisplatin-resistant ovarian cell lines A2780 and A2780cis. A2780 and A2780cis were treated with NaBu alone or in combination with cisplatin (CP). NaBu inhibited the growth of both cell lines and enhanced cytotoxic effect of CP. Exposure to NaBu for 24 h induced cell cycle arrest. The expressions of EMT-related genes and proteins were further investigated by qPCR and western blot analysis. Loss of E-cadherin has been shown to be crucial in ovarian cancer development. We found that NaBu dramatically induce expression of E-cadherin gene (CDH1) and protein levels in A2780 and A2780cis. We investigated correlation between transcription and methylation of CDH1gene. Methylation level analysis in 32 CpG sites in CDH1 gene (promoter/exon1 regions) was performed using bisulfite NGS (Next Generation Sequencing). We found that cisplatin-resistant cell line A2780cis cells differ from their cisplatin-sensitive counterparts in the CDH1 methylation. Methylation in A2780cis cells is elevated compared to A2780. However, NaBu-induced expression of CDH1 was not accompanied by CDH1 demethylation. NaBu treatment induced changes in expression of EMT-related genes and proteins. Interestingly E-cadherin zinc finger transcriptional repressor SNAIL1 was upregulated in both cell lines. Mesenchymal marker vimentin was downregulated. Matrix metalloproteases (MMPs) are necessary for pericellular proteolysis and facilitate migration and invasion of tumour cells. NaBu induced mRNA expression of MMPs, mild changes in activities of gelatinases MMP2 and MMP9 were detected. Our data demonstrate that NaBu sensitizes cisplatin-resistant ovarian cancer cells, re-established E-cadherin expression, but it was not able to reverse the EMT phenotype completely.

Detection of CDH1 gene methylation of suspension cells in abdominal lavage fluid from colorectal cancer patients and its clinical significance

To detect the CDH1 gene methylation of suspension cells in intraoperative abdominal lavage fluid from colorectal cancer patients, and to examine its association with clinicopathology and prognosis. Real-time methylation-specific polymerase chain reaction (qMSP) was used to investigate the methylation status of the CDH1 gene promoter 5'-CpG islands from intraoperative abdominal lavage fluid in 102 patients with colorectal cancer. The associations between methylation of CDH1 genes and clinicopathologic features and prognosis were investigated. Among the 102 colorectal cancer patients, aberrant methylation of CDH1 gene was detected in 47 patients. Significant associations were found between CDH1 methylation status and tumor size, growth pattern, differentiation, distant metastasis, and clinical staging (all P<0.05). The median progression-free survival was 25.98 months for CDH1 methylation group and 41.36 months for non-methylated group, and the difference was statistically significant (P<0.01). Cox model analysis revealed that CDH1 methylation status in intraoperative peritoneal lavage fluid was an independent factor associated with postoperative survival in colorectal cancer patients (50.23% vs. 86.51%, P=0.001). Colorectal cancer patients with aberrant methylation of 5'-CpG of CDH1 gene promoter of suspension cells in abdominal lavage have higher malignancy, more metastasis and worse prognosis.

Loss of expression and aberrant methylation of the CDH1 (E-cadherin) gene in breast cancer patients from Kashmir.

Aberrant promoter hypermethylation has been recognized in human breast carcinogenesis as a frequent molecular alteration associated with the loss of expression of a number of key regulatory genes and may serve as a biomarker. The E-cadherin gene (CDH1), mapping at chromosome 16q22, is an intercellular adhesion molecule in epithelial cells, which plays an important role in establishing and maintaining intercellular connections. The aim of our study was to assess the methylation pattern of CDH1 and to correlate it with the expression of E-cadherin, clinicopathological parameters and hormone receptor status in breast cancer patients of Kashmir. Methylation specific PCR (MSP) was used to determine the methylation status of CDH1 in 128 invasive ductal carcinomas (IDCs) paired with the corresponding normal tissue samples. Immunohistochemistry was used to study the expression of E-cadherin, ER and PR. CDH1 hypermethylation was detected in 57.8% of cases and 14.8% of normal adjacent controls. Reduced levels of E-cadherin protein were observed in 71.9% of our samples. Loss of E-cadherin expression was significantly associated with the CDH1 promoter region methylation (p<0.05, OR=3.48, CI: 1.55-7.79). Hypermethylation of CDH1 was significantly associated with age at diagnosis (p=0.030), tumor size (p=0.008), tumor grade (p=0.024) and rate of node positivity or metastasis (p=0.043). Our preliminary findings suggest that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression. We found significant differences in tumor-related CDH1 gene methylation patterns relevant to tumor grade, tumor size, nodal involvement and age at diagnosis of breast tumors, which could be extended in future to provide diagnostic and prognostic information.

Role of CDH1 Promoter Polymorphism and DNA Methylation in Bladder Carcinogenesis: A Meta-Analysis

Increasing scientific evidences suggest that CDH1 gene promoter polymorphism and DNA methylation may contribute to the development and progression of bladder cancer, but many existing studies have yielded inconclusive results. This meta-analysis aims to assess the role of CDH1 gene promoter polymorphism and methylation in bladder carcinogenesis. An extensive literature search for relevant studies was conducted in PubMed, Embase, Web of Science, Cochrane Library, and CBM databases from their inception through April 1, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude odds ratio with 95% confidence interval was calculated. Fifteen studies were included in this meta-analysis with a total of 824 bladder cancer patients and 818 healthy controls being assessed. Our meta-analysis revealed that the A variant of CDH1 -160C/A polymorphism was associated with an increased risk of bladder cancer. Further analysis by pathological subtype indicated that patients with invasive carcinoma had a higher frequency of CDH1 -160A variant than those with superficial carcinoma. We analyzed the methylation frequency of CDH1 gene in 608 bladder cancer samples and 338 normal bladder samples. Our data strongly suggest that the CDH1 promoter methylation frequencies in bladder cancer tissues were greater than those in normal control tissues. In conclusion, our meta-analysis indicates that promoter polymorphism and methylation of CDH1 gene may be involved in the development and progression of bladder cancer. CDH1 gene promoter polymorphism and methylation might be promising biomarkers for the diagnosis and prognosis of bladder cancer.

Effect of CDH1 gene methylation on transforming growth factor (TGF-β)-induced epithelial-mesenchymal transition in alveolar epithelial cell line A549

The aim of this study was to investigate the specific molecular mechanism of the transforming growth factor β (TGF-β)-induced epithelial-mesenchymal transition in a lung cancer cell line, and to provide new ideas for targeting therapy of lung cancer. A549 cells were treated with different concentrations of TGF-β and 5-aza-deoxycytidine (5-aza-dC). The morphological changes after the intervention were observed. The change in the expression of the epithelial marker E-cadherin (E-cad) was detected by Western blot. The proliferation of A549 cells was measured using the MTT assay. Cell movement and invasion capacity was evaluated with the cell scratch test and invasion test. TGF-β induced A549 cells to transform to a mesenchymal cell morphology and downregulated the expression of E-cad, and 5-aza-dC inhibited this phenomenon. Compared with the control group, the number of transmembrane cells was higher and cell migration was markedly increased in the experimental group with continued culture in the presence of 10 ng/mL TGF-β, showing significant differences (P < 0.05). CDH1 gene methylation is involved in TGF-β-induced epithelial-mesenchymal transition in the alveolar epithelial cell line A549.

Methylation status of CDH1 gene in preoperative abdominal lavage of patients with gastric cancer and its clinical significance

To explore the association between the progression of gastric cancer and the aberrant methylation of CDH1 gene in preoperative abdominal lavage fluid. Real-time methylation-specific polymerase chain reaction(qMSP) was used to investigate the methylation status of the CDH1 gene promoter 5'-CpG islands from preoperative abdominal lavage fluid in 92 patients with gastric cancer. The associations between methylation of CDH1 genes and clinicopathologic features and prognosis were investigated. Among the 92 patients with gastric cancer, aberrant methylation of CDH1 gene was detected in 45(48.9%) patients, including total aberrant methylation in 12(13.0%) cases and partly aberrant methylation in 33(35.9%) cases. Significant associations were found between CDH1 methylation status and tumor size, growth pattern, differentiation, lymphovascular invasion, infiltration depth, lymph node metastasis, distant metastasis, and clinical staging(all P<0.05). However, there were no significant associations between CDH1 methylation status with gender, age, tumor location, or Helicobacter pylori infection(all P>0.05). The median progression-free survival was 20 months for CDH1 methylation group and 38 months for non-methylated group, and the difference was statistically significant(P<0.01). Cox model analysis revealed that CDH1 methylation status in preoperative peritoneal lavage fluid was an independent factor associated with postoperative survival in patients with gastric cancer(P=0.000, RR=332.88, 95%CI:21.71-5105.07). The aberrant methylation of 5'-CpG of CDH1 gene promoter is common in gastric cancer. The examination of CDH1 methylation status of abdominal lavage should be considered in the progression of gastric cancer.

The expression of CDH1 gene methylation in patients with esophagus and stomach double primary carcinoma and its significance

Objective To study the changes of CDH1 gene promoter CpG island methylation and its clinical significance in patients with esophagus and stomach double primary carcinoma(ESDC).Methods The expression of CDH1 gene methylation in cancerous tissues and adjacent cancerous tissues in 18 cases of ESDC were detected using methylation-specific PCR method. Results Eighteen patients were endoscopically diagnosed as ESDC between Jan. 2007 and Sep. 2009 in the 4th Hospital Affiliated to Hebei Medical University. The positive methylation of CDH1 gene in tissues of esophageal squamous cell carcinoma (ESCC)and adjacent cancer were 66.7% and 33. 3%, respectively, with significant difference (χ2= 4. 167, P = 0. 031). Whereas the positive methylation of CDH1 gene in tissues of gastric carcinoma (GA) and adjacent cancer were 77.8% and 44.4%, respectively, without statistical difference (χ2=1.786, P= 0. 180). There was no significant difference (P=0. 500) in positive rate of CDH1 gene methylation between ESCC tissues and GA tissues in same individual with ESDC. For 18 patients with ESDC, consistent change of CDH1 methylation in tissues of two kinds of cancers was found in 16 patients with a total agreement of 88.9 % (positive agreement of 66.7 % and negative agreement of 22. 2%). Statistical analysis showed a significant correlation between two groups (P = 0. 005). Conclusion In patients with ESDC, there is a high consistency of CDH1 methylation change, between ESCC and GA,which suggests that two kinds of cancer may have similar risk factors and molecular mechanisms. Key words: Stomach neoplasms; Esophasus neoplas double primary carcinoma; Esophageal squmaous cell carcinoma; CDH1; Methylatlion

Abstract 4940: E-cadherin methylation is preceded in normal mucosa of diffuse type gastric carcinoma

Abstract Background: The importance of loss of E-cadherin (encoded by CDH1) to cancer progression is well established. CDH1 is mutationally inactivated in nearly half of diffuse type gastric cancer (DGC). Although CDH1 promoter methylation has been suggested to be a major second hit in hereditary diffuse gastric cancer, its role in sporadic DGCs is not clarified. Searching for the second hit methylation in potential precursor lesions in sporadic DGC, we investigated the CDH1 methylation frequency in a series of DGCs and matching normal mucosas and then compared the result with the CDH1 methylation frequency in normal mucosas from benign gastric pathology. Materials and Methods: The extent of promoter methylation of CDH1 gene was assessed quantitatively using Pyrosequencing in 72 DGCs with two matching normal mucosas from adjacent and remote foci, and 24 normal gastric mucosa samples from patients with benign gastric pathology. Gene product was studied by immunohistochemistry and the relationship between methylation profile of gene promoter and clinicopathological parameters was analyzed. Results: The Pyrosequencing analysis of DGCs revealed a high frequency of CDH1 methylation in 77.8% (56/72). The methylation frequency for CDH1 gene in matching normal mucosas from adjacent and remote foci was 70.8% (51/72) and 72.2% (52/72), respectively. According to the distance from the tumor location the result did not show significant difference. Moreover, total of 65 out of 72 cases (90.3%) showed at least one focus with CDH1 methylation. Frequency of CDH1 methylation in normal gastric mucosa samples with benign gastric pathology was 50.0% (12/24). There was a significant difference of CDH1 methylation in between normal mucosas from DGCs and normal mucosas with benign gastric pathology (90.3% vs. 50.0%, respectively, p&amp;lt;0.001). CDH1 methylation in matching normal gastric mucosas was counted as a statistically significant risk factor when adjusted for age and sex using a binary logistic regression model (p&amp;lt;0.001). Additionally loss or diminished expression of E-cadherin was confirmed by immunohistochemistry in 69 of 72 tumor samples (96.9%) and its down expression was not uncommonly observed in adjacent normal gastric mucosas. Conclusion: We found that CDH1 promoter methylation in the normal gastric mucosas from DGC samples was significantly higher than in the normal gastric mucosas with benign pathology but had a similar frequency with tumor tissues. These results suggest that CDH1 gene methylation may be important in the initial development of sporadic DGC tumorigenesis and the presence of DGC progenitor cells may be traced by the E-cadherin down-expression in normal gastric mucosa from different foci. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4940.

Methylation status of CDH1 gene in samples of gastric mucous from brazilian patients with chronic gastritis infected by Helicobacter pylori

Gastric cancer is one of the top list of cancer types that most leads to death in Brazil and worldwide. Helicobacter pylori(H. pylori) is a class I carcinogen and infect almost 90% of chronic gastritis patients. Some genotypes confer different virulent potential to H. pylori and can increase the risk of gastritis development. Methylation of CpG islands can inactivate tumor suppressor genes and therefore, it can be involved in the tumorigenic process. CDH1 is a tumor suppressor gene that encodes the E-cadherin protein, which is important in maintaining cell-cell contacts. The inactivation of this gene can increase the chance of metastasis. Promoter methylation of CDH1 at early steps of gastric carcinogenesis is not yet completely understood. In this study, we investigated the methylation status of CDH1 in chronic gastritis samples and correlated it with the presence of H. pylori. Sixty gastric mucosal biopsies were used in this study. The detection of H. pylori was performed with the PCR primers specific to urease C gene. H. pylori genotyping was performed by PCR to cagA and vacA (s and m region). The methylation status of these gene CDH1 was analyzed using methylation-specific polymerase chain reaction and direct sequencing of the PCR products was performed using primers methylated and unmethylated in both forward and reverse directions. H. pylori was detected in 90% of chronic gastritis samples; among these 33% were cagA positive and 100% vacA s1. The genotype vacA s2/m1 was not detected in any sample analyzed. Methylation of CDH1 was detected in 63.3% of chronic gastritis samples and 95% of them were also H. pylori-positive. This work suggests that CDH1 gene methylation and H. pylori infection are frequent events in samples from Brazilian patients with chronic gastritis and reinforces the correlation between H. pylori infection and CDH1 inactivation in early steps of gastric tumorigenesis.

Estudio de patrones de metilación génica en tumores del tubo digestivo

The loss of tumor suppressor gene function damages the defensive mechanisms that protect the indemnity of genetic material. Promoter gene methylation is one of the inactivation mechanisms of suppressor genes.To study the methylation pattern of a group of genes in biopsy samples of gastrointestinal tumors.Forty eight gastric, 25 gallbladder, 24 colon and 6 pancreas cancer biopsy samples were randomly selected. The methylation pattern of CDH1, FHIT, CDKN2A, APC and MLH1 genes, was studied using a specific polymerase chain reaction test for methylation. Demographic, morphological and follow up variables of patients bearing the tumors were also analyzed.The general methylation frequency of CDH1, FHIT, CDKN2A, APC and MLH1 genes was 64.1, 56, 39.8, 18.1 and 34% respectively. In gastric cancer samples there was a correlation between APC gene methylation and well differentiated tumors; between CDH1 methylation and Lauren diffuse type and the presence of three or more metastasic lymph nodes; between FHIT, CDKN2A and CDH1 gene methylation and male gender. In less differentiated gallbladder tumors, the frequency of CDH1 methylation was higher. There was a tendency towards a lower survival in colon and gastric cancer when MLH1 (p =0.07) y CDKN2A (p= 0.06) were methylated, respectively.An abnormal methylation pattern was associated with morphological features in gastric and gallbladder cancer and with a tendency towards a lower survival in colon and gastric cancer.

Gene methylation patterns in digestive tumors

The loss of tumor suppressor gene function damages the defensive mechanisms that protect the indemnity of genetic material. Promoter gene methylation is one of the inactivation mechanisms of suppressor genes. To study the methylation pattern of a group of genes in biopsy samples of gastrointestinal tumors. Forty eight gastric, 25 gallbladder, 24 colon and 6 pancreas cancer biopsy samples were randomly selected. The methylation pattern of CDH1, FHIT, CDKN2A, APC and MLH1 genes, was studied using a specific polymerase chain reaction test for methylation. Demographic, morphological and follow up variables of patients bearing the tumors were also analyzed. The general methylation frequency of CDH1, FHIT, CDKN2A, APC and MLH1 genes was 64.1, 56, 39.8, 18.1 and 34% respectively. In gastric cancer samples there was a correlation between APC gene methylation and well differentiated tumors; between CDH1 methylation and Lauren diffuse type and the presence of three or more metastasic lymph nodes; between FHIT, CDKN2A and CDH1 gene methylation and male gender. In less differentiated gallbladder tumors, the frequency of CDH1 methylation was higher. There was a tendency towards a lower survival in colon and gastric cancer when MLH1 (p =0.07) y CDKN2A (p= 0.06) were methylated, respectively. An abnormal methylation pattern was associated with morphological features in gastric and gallbladder cancer and with a tendency towards a lower survival in colon and gastric cancer.

Hypermethylation status of E-cadherin and p16INK4a in gastrointestinal stromal tumor

To investigate the methylation status of CpG island in E-cadherin(CDH 1 ), P16INK4a(P16) promoter region,and to analyze their role in gastrointestinal stromal tumor (GISTs). A total of 56 surgically resected GISTs were obtained from January 2003 to December 2005. The routine H&E-stained sections and CD117, CD34-immunoreactions were reviewed to verify the morphologic diagnosis. Methylation status of the CDH 1 , P16INK4a promoter region was analyzed by methylation specific polymerase chain reaction (MSP) from chemically modified DNA after Na-bisulfite treatment. The frequency of CDH 1 gene methylation was 32% (18 of 56) in GISTs. The rate was 9% (1 of 11), 21% (4 of 19), 41.6% (5 of 12), and 57% (8 of 14) for very low risk, low risk, intermediate risk, and high risk GISTs; P16 INK4a methylation was found in 19 of 56(34%) cases. The rate was 0% (0 of 11), 16% (3 of 19), 50% (6 of 12), and 71% (10 of 14) for very low risk, low risk, intermediate risk, and high risk GISTs. Statistical analysis indicated that of the 56 cases, there was significant association of CDH 1 and/or P16 INK4a methylation status with tumor malignant behavior (methylation rate 23/56, 41%, P<0.01) and site (P<0.05). E-cadherin (CDH 1 ) and/or P16 INK4a promoter hypermethylation is strongly associated with risk grade, may be a useful biomarker for GISTs risk assessment, and may shed light on new therapeutic options to treat GISTs

Disordered beta-catenin expression and E-cadherin/CDH1 promoter methylation in gastric carcinoma

To investigate the distribution of beta-catenin in nuclei or membrane/cytoplasm of gastric carcinoma cells, the relationship between E-cadherin gene methylation and its expression, and the role of beta-catenin and E-cadherin as potential molecular markers in predicting tumor infiltration. Twenty-nine cases of gastric carcinoma, classified as diffuse and intestinal variants, were selected for study. Nuclear and cytoplasmic proteins were purified and beta-catenin content was detected by ELISA. DNA methylation of E-cadherin/CDH1 gene promoter was studied by methylation-specific PCR and compaired with E-cadherin expression detected by immunohistochemistry. In 27 cases of gastric carcinoma, the ratio of beta-catenin content between nuclei and membrane/cytoplasm was correlated with the T-classification (r = 0.392, P = 0.043). The significance was present between T2 and T3 groups. No correlation was detected between diffuse and intestinal variants in terms of their beta-catenin distribution. In 21 cases of diffuse variants of gastric carcinoma, there was a difference in E-cadherin expression between CDH1 gene-methylated group and non-methylated group (29 % vs 71 %, P = 0.027). No correlation between CDH1 gene methylation and T-classification was found, neither was the significance between E-cadherin expression and tumor infiltration grade. Comparative analysis of nuclear and membrane/cytoplasmic beta-catenin can predict local tumor infiltration. E-cadherin/CDH1 gene methylation is an important cause for its gene silence in diffuse variant gastric carcinoma. Methylation of CDH1 gene in the absence of E-cadherin is an early event in gastric carcinogenesis.