Expression of gastrin and its receptor in human gastric cancer tissues

Gastrin is a growth factor of cancerous and normal cells of the gastrointestinal tract, and its effect is known to be mediated by gastrin/cholecystokinin B (CCKB) receptor. This study was performed to investigate the prognostic significance and the expression profiles of gastrin and gastrin receptor in human gastric carcinoma tissues.

We analyzed the expressions of gastrin and gastrin receptor by immunohistochemical staining using anti-gastrin Ab (Sigma, St. Louis, MO, USA) and anti-gastrin receptor Ab (Aphton Corp., Woodland, CA, USA) in 279 gastric adenocarcinoma patients. Patients' clinicopathologic features and prognoses were analyzed.

The gastrin expression rate in these patients was 47.7% (133/279) and the gastrin receptor expression rate was 56.5% (158/279). Gastrin expression was significantly higher in men than in women (54.3% vs. 34.1%), and higher in differentiated gastric adenocarcinoma than in the undifferentiated type (55.1% vs. 43.0%). The gastrin receptor expression rate was also significantly higher in men than in women (61.2% vs. 47.3%), and was higher in the differentiated type than in the undifferentiated type (72.9% vs. 46.5%), and significantly higher in the intestinal type than in the diffuse type (75.2% vs. 42.9%). Gastrin and gastrin/CCKB receptor expressions were not found to be significant prognostic factors in themselves. When focused on correlation between the co-expression of gastrin and gastrin/CCKB receptor and the survival, the prognosis of patients positive for both gastrin and gastrin receptor was significantly poorer than for those negative for gastrin and gastrin receptor in diffuse-type gastric cancer patients. However, multivariate analysis showed that only TNM stage was an independent prognostic factor of survival in diffuse-type gastric cancer patients.

This study shows that the expression rates of gastrin and gastrin receptor are high (about a half) in gastric carcinoma tissues, and that there is an association between gastrin and gastrin receptor expression. We also found that patients with diffuse-type gastric carcinoma tissues expressing both gastrin and gastrin receptor have a poorer prognosis than those negative for both, which suggests that gastrin acts as an autocrine growth factor in a subgroup of gastric carcinomas.