Clinicopathological implications of EpCAM immunoexpression in canine gastric carcinoma and its association with other immunomarkers

Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein, and its overexpression has been reported in various human epithelial cancers, namely in gastric cancer. This study evaluated the EpCAM immunohistochemical expression pattern in canine tissue samples: non-neoplastic gastric mucosa (n = 14) and gastric carcinoma (n = 31). EpCAM was consistently expressed in all cases of non-neoplastic gastric mucosa and in 96.8 % of gastric carcinomas, 64.5 % of which showed EpCAM overexpression. EpCAM overexpression was statistically more frequent in intestinal type carcinomas (100.0 %; p = 0.036) than in diffuse-type carcinomas (47.4 %), according to Lauren classification. No statistically significant differences in EpCAM expression were observed regarding sex, age, body weight, tumour location, tumour depth and histological type according to the human WHO classification. EpCAM overexpression was associated with previously studied markers of canine gastric cancer, namely E-cadherin, TFF1, vimentin and Ki-67 and a significantly association between EpCAM overexpression and high Ki-67 proliferative index in neoplastic cells of gastric carcinomas was observed (Kappa=0.358; p = 0.042). Our results demonstrate that EpCAM is expressed in canine gastric tissues and overexpressed in gastric carcinomas, being potentially involved in the gastric carcinogenesis in dogs.