Correlation of E- and N-cadherin expressions as a prognostic factor in metastatic and nonmetastatic gastric tumors.

Abstract

e16028 Background: Over the past 10 years, gastric cancer has been in the top five most common malignant tumors with a high mortality rate. Its poor prognosis is determined by the aggressive disease course with the development of distant metastases. Additional markers of tumor progression are required, and a special role in tumor progression is assigned to the epithelial-mesenchymal transition (EMT). E- and N-cadherins are among the key EMT regulators. Our purpose was to reveal possible prognostic value of EMT markers in different forms of gastric cancer. Methods: The study included patients (aged 30-80 years) with gastric cancer: control group (n = 20, 58.9±9.7 years) – non-metastatic gastric cancer T3-4аN0-3M0 (G2); main group (n = 20, 53.4±11.9 years) – gastric cancer T3-4аN0-3M1 (G2) with peritoneal metastases. IHC analysis was performed on sections from paraffin tumor blocks using mouse monoclonal antibodies to E-cadherin (SMP471, Diagnostic BioSystems) and N-cadherin (SP90, Spring Bioscience) diluted 1:30, and the Reveal Polyvalent HRP-DAB Detection System. Expression of E- and N-cadherins was analyzed semi-quantitatively according to the percentage of cells showing membrane positivity and the intensity of staining: 0 (from 0 to 10%); 1+ (from 11 to 30%); 2+ (from 31 to 70%); 3+ ( > 70%). Expression was considered positive in ≥2. Statistical analysis of results was performed in the Statistica 13.0 program (StatSoftInc., USA) using the Pearson's chi-square test and the Spearman's correlation. Results: Maximal staining for E-cadherin was observed in the control group (in 90%), staining for N-cadherin – in the main group (in 70%). Average expressions of E- and N-cadherins were: in controls – 34.5±4.5 and 24.1±5.7; in the main group – 24.6±5.8 and 28.3±4.3. The Pearson's test showed the statistically significant prevalence of patients with E-cadherin+ tumors in the control group (7.619, p = 0.006), and the prevalence of patients with N-cadherin+ tumors in the main group (4.912, p = 0.027). However, when considering the correlation between E-cadherin and N-cadherin in the groups, the Spearman's correlation was not statistically significant (rs = -0.342 in the control group and rs = -0.430 in the main group at p > 0.05). Conclusions: The study revealed only a tendency towards the loss of E-cadherin and increased expression of N-cadherin, which is often associated with a poor prognosis. However, a more extensive study is required to assess the possible prognostic value of these EMT markers in metastatic and non-metastatic gastric cancer.