Clinicopathologic evaluation of immunohistochemical E-cadherin expression in human gastric carcinomas

Expression of metastasis-associated gene 1, PTEN and E-cadherin in gastric carcinoma and their correlations

AIM: To investigate the expression of metastasis-associated gene 1 (MTA1), PTEN and E-cadherin in gastric carcinoma and normal gastric mucosa and their relationships with the invasion, metastasis and biological behavior of gastric carcinoma.

METHODS: Immunohistochemistry was used to examine the expression of MTA1, PTEN and E-cadherin proteins in gastric carcinoma (n = 54) and normal gastric mucosa (n = 15). The data were processed by chi-square test and the correlation was analyzed by Spearman test.

RESULTS: In comparison with those in normal gastric mucosa, the expression of MTA1 in gastric carcinoma was significantly higher (46.3% vs 6.7%, P < 0.01), and the expression of PTEN and E-cadherin in gastric carcinoma were down-regulated or even disappeared (51.9% vs 100%, 42.6% vs 100%; both P < 0.01). The expression of MTA1 and PTEN were correlated with the invasion depth (P = 0.003, P = 0.001), pathological grades (P = 0.004, P = 0.008), lymph node metastasis (P = 0.000, P = 0.001), distant metastasis (P = 0.004, P = 0.006) and clinical classification (P = 0.001, P = 0.000), and the normal expression of E-cadherin had relationship with the invasion depth (P = 0.027), pathological grades (P = 0.006), lymph node metastasis (P = 0.044), and clinical classification (P = 0.000). There was a negative correlation between the expression of MTA1 and PTEN as well as between the expression of MTA1 and E-cadherin (r = -0.518, r = -0.424; both P < 0.05), but there was a positive correlation between the expression of PTEN and E-cadherin (r = 0.53, P < 0.05).

CONCLUSION: High expression of MTA1 and low expression of PTEN and E-cadherin may be associated with the invasion and metastasis of gastric carcinoma. Combined examination of three indexes may be used to evaluate the biological behavior of gastric carcinoma.

Syndecan-1 and E-cadherin expression in differentiated type of early gastric cancer

AIM: To elucidate the role and alterations of syndecan-1 and E-cadherin expression in different cellular phenotypes of differentiated-type gastric cancers (DGCs).

METHODS: A total of 120 DGCs at an early stage, and their adjacent mucosa, were studied both by immunohis-tochemistry. Syndecan-1 and E-cadherin were assessed by immunohistochemical staining with anti-syndecan-1 and anti-E-cadherin antibodies, respectively. Based on immunohistochemistry, DGCs and their surrounding mucosa were divided into four types: gastric type (G-type), ordinary type (O-type), complete-intestinal type (CI-type), and null type (N-type).

RESULTS: Syndecan-1 expression was significantly lower in G-type cancers (29.4%) than in O-type (79.6%) and CI-type cancers (90%) (P<0.05, respectively), but E-cadherin did not show this result. In addition, syndecan-1 expression was significantly reduced in DGCs comprised partly of poorly differentiated adenocarcinoma or signet-ring cell carcinoma, compared to DGCs demonstrating papillary and/or tubular adenocarcinoma (P<0.05). G-type intestinal metaplasia (IM) surrounding the tumors was observed in 23.8% of G-type, 4.9% of O-type, and 6.7% of CI-type cancers (P<0.05; G-type vs O-type). Reduction of syndecan-1 expression was significant in G-type IM (25%) compared to non-G-type IM (75%; P<0.05).

CONCLUSION: Loss of syndecan-1 plays a role in the growth of G-type cancers of DGCs at an early stage, and the reduction of syndecan-1 expression in IM surrounding the tumors may influence the growth of G-type cancer.