Expression of hGC-1 is correlated with differentiation of gastric carcinoma

Aims: The human G-CSF-stimulated clone-1 (hGC-1) gene encodes a 510-amino acid olfactomedin-related glycoprotein whose exact in vivo localization and function still remain elusive. The aim of this study was to demonstrate hGC-1 protein localization in the normal human gastrointestinal tract and to explore further a potential relationship between hGC-1 expression and gastric carcinoma. Methods and results: A specific hGC-1 polyclonal antibody raised against purified hGC-1 protein was developed and characterized. Using immunohistochemistry, it was demonstrated that hGC-1 is expressed in the oesophagus, stomach, small intestine and colon. The expression pattern of hGC-1 protein in 173 cases of gastric carcinoma was investigated and a striking correlation was demonstrated between hGC-1 expression and histological type and differentiation of gastric carcinoma. Enhanced hGC-1 expression was more frequently seen in intestinal-type adenocarcinoma, whereas loss of expression tended to occur in the diffuse type. hGC-1 was highly expressed in well or moderately differentiated cancers and was remarkably reduced or lost in poorly differentiated or undifferentiated tumours. Conclusions: These investigations have defined for the first time the expression pattern of hGC-1 in the normal human gastrointestinal tract and provide a novel and sensitive marker for the differentiation of gastric carcinoma.