Expression of the E-cadherin/catenin (alpha-, beta-, and gamma-) complex correlates with the macroscopic appearance of early gastric cancer

Abnormal β-catenin immunohistochemical expression as a prognostic factor in gastric cancer: A meta-analysis

AIM: To evaluate the effect of β-catenin immunohistochemical expression on the prognosis of gastric cancer (GC).

METHODS: We searched Pubmed and Embase to identify eligible studies. The search ended on November 10, 2013, with no lower date limit. The citation lists associated with the studies were used to identify additional eligible studies. We included studies reporting sufficient information to estimate the HR and 95%CI, and information to estimate the OR in the analysis of clinicopathological features. The qualities of these studies were assessed using the Newcastle-Ottawa Quality Assessment Scale. HRs and ORs and their variance were calculated and pooled using Review Manager Version 5.2.

RESULTS: A total of 24 studies were identified and comprised 3404 cases. β-catenin expression was significantly correlated with poor overall survival (OS) in GC patients (HR = 1.85, 95%CI: 1.39-2.46), but showed a significant degree of heterogeneity (I² = 71%, P < 0.0001). Subgroup analysis indicated that an abnormal pattern of β-catenin expression had an unfavorable effect on OS (HR = 1.79, 95%CI: 1.39-2.32). However, accumulation in the nucleus or loss of membrane did not influence the survival of GC patients independently. Moreover, the combined OR of β-catenin indicated that β-catenin expression was associated with Lauren classification (OR = 1.98, 95%CI: 1.19-3.29), lymph node metastasis (OR = 2.00, 95%CI: 1.44-2.77), distant metastasis (OR = 2.69, 95%CI: 1.35-5.38) and grade of differentiation (OR = 2.68, 95%CI: 1.66-4.34). β-catenin expression did not correlate with TNM stage (OR = 1.34 95%CI: 0.96-1.86), the depth of invasion (OR = 1.48, 95%CI: 0.94-2.33) or vascular invasion (OR = 1.11, 95%CI: 0.70-1.76).

CONCLUSION: Abnormal β-catenin immunohistochemical expression may be associated with tumor progression and could be a predictive factor of poor prognosis in patients with GC.

Mechanisms inactivating the gene for E-cadherin in sporadic gastric carcinomas

AIM: To study the role of CDH1/E-cadherin (E-cad) gene alteration profiles including mutation, loss of heterozygosity (LOH), promoter polymorphism and hypermethylation in mechanisms of CDH1 inactivation in gastric carcinoma (GC).

METHODS: Specimens were collected surgically from 70 patients with GC. Allelotyping PCR and detection of LOH, denaturing high pressure liquid chromatography and DNA sequencing, restriction fragment length polymorphism analysis, methylation specific PCR, and immunohistochemical staining were used.

RESULTS: Promoter polymorphism was not a major mechanism of E-cad inactivation. Only one truncating mutation was found in a diffuse type tumor (3%). Both LOH and promoter hypermethylation were major mechanisms of E-cad inactivation, but interestingly, there was a negative association between the fraction of allelic loss (LOH) in tumors and hypermethylation of CDH1. Therefore LOH and hypermethylation were two different tumorigenic pathways involved in GC.

CONCLUSION: Given the findings that somatic mutation was extremely low and the relationship between LOH and hypermethylation was inverse, any two combinations of these three factors cannot fulfill the classical two-hit hypothesis of CDH1 inactivation. Thus, other mechanisms operating at the transcriptional level or at the post-translational level might be required to induce E-cadherin inactivation.

α-catenin expression is decreased in patients with gastric carcinoma

AIM: To assess the expression of α-catenin in gastric carcinoma and to determine the role of α-catenin expression in gastric carcinogenesis.

METHODS: α-catenin expression was assessed by semi-quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical staining in 49 gastric carcinomas, 26 adjacent non-cancerous mucosae, and gastric biopsy specimens from 11 healthy controls.

RESULTS: mRNA levels of α-catenin were reduced or absent in 34 of 49 (69%) gastric carcinoma tissues and in 5 of 26 (19%) tumor-free gastric mucosae of carcinoma patients, respectively. Of the carcinoma samples with altered α-catenin mRNA levels, α-catenin expression was negative in 20 and decreased in 14 cases. Up to 69% of tumors were stained abnormally for α-catenin. Of the 34 cases whose mRNA expression of α-catenin was reduced, 32 (94%) showed abnormal immunostaining patterns, while only 2 showed a normal α-catenin expression. The frequency of reduced expression of α-catenin mRNA was 14% in well-differentiated carcinomas, higher than that in poorly differentiated carcinomas (86%). A significant correlation was not shown between α-catenin expression and both depth of invasion and lymph node metastasis. Moreover, there was no statistical difference between loss or down-regulation of α-catenin mRNA and Helicobacter pylori (H pylori) infection.

CONCLUSION: Downregulation of α-catenin expression is common in gastric carcinoma, and α-catenin expression may be used as a differentiation marker. Downregulation of α-catenin expression may be an early event in tumorigenesis. Reduced α-catenin expression is not correlated with H pylori infection.

Relationship between abnormal expression of α-catenin and biological behaviors of gastric carcinoma

AIM

To assess the expression of α-catenin in gastric carcinoma and to determine its relation with tumor clinicopathological features and patient survival.

METHODS

Immunohistochemical staining of α-catenin was performed for 163 cases of gastric carcinomas,44 cases of gastric dysplasia and 25 cases of intestinal metaplasia,and 28 cases of atrophic gastritis.

RESULTS

Normal membranous staining was observed in intestinal metaplasia and control biopsy specimens for α-catenin. 76% of tumors and 43% of gastric dysplasia were stained abnormally for α-catenin. Only one of atrophic gastritis showed abnormal staining. Abnormal α-catenin expression occurred more significantly in Borrmann III/IV type than in Borrmann I/II type (P <0.01) A significantly higher proportion of signet-ring (91%), mucinous(79%) and tubular adenocarcinomas (78%) showed abnormal α-catenin expression compared with papillary adenocarcinomas (47%) (P <0.01) Morever, abnormal α-catenin staining occurred more frequently in diffuse type(95%, 38/40) than in intestinal type tumors (68%, 73/108) (P <0.01). No association was found between abnormal α-catenin and tumour invasive depth, lymph node metastasis and distance metastasis (P >0.05, respectively). A survival advantage was not noted in the tumors retaining normal staining of α-catenin.

CONCLUSION

Abnormal expression of α-catenin occurs frequently in gastric carcinoma, and is closely related to its poor differentiation. Abnormal expression of α-catenin in gastric dysplasia may be an early event in tumorigenesis.

Expression of E-cadherin and β-catenin in gastric carcinoma and its correlation with the clinicopathological features and patient survival

AIM: The E-cadherin-catenin complex is important for cell-cell adhesion of epithelial cells. Impairment of one or more components of this complex is associated with poor differentiation and increased invasiveness of carcinomas. We evaluated the expression pattern of E-cadherin and β-catenin in gastric carcinoma and dysplasia and analyzed their relationship with tumor clinicopathological features and patient survival.

METHODS: Immunohistochemical staining of E-cadherin and β-catenin was performed from paraffin specimens of 163 gastric carcinomas, 44 gastric mucosal dysplasia, and 25 intestinal metaplasia, 28 atrophic gastritis and 12 healthy controls.

RESULTS: Normal membrane staining was observed in intestinal metaplasia, atrophic gastritis and control biopsy specimens for E-cadherin and β-catenin. 36% and 16% of gastric dysplasia were stained abnormally for E-cadherin and β-catenin respectively. Abnormal expression of E-cadherin and β-catenin was demonstrated in 46% and 44% of gastric carcinoma respectively. Abnormal expression of E-cadherin and β- catenin occurred more significantly in Borrmann III/IV than in Borrmann I/II type (P < 0.005, respectively). A significantly higher proportion of signet-ring, mucinous and tubular adenocarcinomas were abnormally expressed for E-cadherin and β-catenin as compared with papillary adenocarcinomas (χ² = 8.47, P < 0.005, and χ² = 7.05, P < 0.01, respectively). Morever, abnormal E-cadherin and β-catenin staining occurred more frequently in diffuse than in intestinal type of tumor (χ² = 18.18 and 17.79, P < 0.005, respectively). There was a significant correlation between abnormal β-catenin expression and positive lymph node metastasis. A survival advantage was noted in tumors retaining normal membranous expression of β-catenin, independent of type, grade, or stage of the disease (P < 0.0005).

CONCLUSION: Abnormal expression of the E-cadherin-catenin complex occurs frequently in gatric carcinoma, closely related to its histogenesis. Abnormal expression of the E-cadherin- catenin complex in gastric dysplasia may be an early event in the tumorigenesis. The close correlation with poor survival suggests that abnormal β-catenin may be a useful prognostic marker.