CDX2 expression in the stomach with intestinal metaplasia and intestinal-type cancer: Prognostic implications.

CDX2, a transcriptional factor expressed in the intestine, is implicated in the development and maintenance of the intestinal mucosa. Recent studies have demonstrated that CDX2 is expressed in the intestinal metaplasia of the stomach and intestinal-type gastric cancer, while it is not expressed in the normal gastric mucosa. To investigate the role of CDX2 in gastric cancer, we determined CDX2 expression and cell proliferation rate in various types of gastric cancer tissues by immunostaining. Surgically dissected gastric cancer tissues were collected from 40 patients. Consistent with previous reports, CDX2 was expressed in most gastric mucosa samples with intestinal metaplasia (89%, 16/18), although it was not found in the adjacent normal mucosa. CDX2 expression was also detected in 64% (18/28) of intestinal-type gastric cancer cases, whereas it was not observed in the diffuse-type gastric cancer (0/12). Moreover, the CDX2-positive gastric cancer samples showed significantly lower index for Ki-67 immunostaining, indicating reduced cell proliferation rates than in the CDX2-negative samples. Importantly, multivariate analysis for the overall survival rate revealed that the CDX2-positive gastric cancer patients survived significantly longer than the CDX2-negative patients. Even among the intestinal-type gastric cancer cases, the CDX2-positive group showed a lower Ki-67 index and longer postoperative survival than the CDX2-negative group. These results collectively indicate that CDX2 expression in gastric cancer tissues can be a novel prognostic marker for patient survival.