The Expression And Significance Of Caudal Type Homeobox Transcription Factor 2 In Gastric Carcinomas, Colorectal Carcinomas And Its Hepatic Metastases

Objective CDX2 was expressed specifically in the epithelium of intestine, recent studies have demonstrated that CDX2 play an important role in tumor genesis. The aim of this study was: 1) to assess the role of CDX2 in the pathogenesis of gastric carcinomas(GC) and gastric intestinal metaplasia(IM). 2) to investigate the role of CDX2 in colorectal carcinomas(CRC) and to verify whether CDX-2 can be a reliable marker to identify the colorectal origin of hepatic metastases.Methods 1) By immunohistochemistry, expression of CDX2 were evaluated in surgically dissected GC tissues from 49 patients and gastric IM tissues from 20 patients, cell proliferation rate were evaluated in the GC tissues. 2) Expression of CDX2 was evaluated in formalin-fixed, paraffin-embedded samples(38 surgically resected CRC, 20 PHC, and 15 hepatic metastases from CRC). Meanwhile, serum AFP,CEA levels were determined in the hepatic lesion patients. Results 1) CDX2 nuclear staining was observed in 90%(18/20) of IM and 59.1%(29/49) of GC, a significant association was observed between CDX2 expression and the histological type of GC. Moreover, the CDX2-positive GC samples showed significantly lower index for Ki-67 immunostaining than the CDX2-negative GC samples, indicating reduced cell proliferation rates. The similar result was observed among the intestinal-type GC cases. Moreover, the CDX2-positive group showed tendencies of less invasiveness and fewer lymph node metastases. 2) CDX2 was expressed in 94.7%(36/38) of CRC cases and 100%(15/15) of hepatic metastasis cases, no expression was detected in PHC cases. In the patients with hepatic metastases, the CDX2 positive rates was higher than the positive rates of serum AFP and CEA.Conclusions These results collectively indicate: 1) CDX2 protein play an important role in genesis of IM and GC. CDX2 exppression in GC can not be use for early diagnosis of GC, but it can be a novel prognostic marker for tumor invasion and patients survival. 2) Expression of CDX2 in colorectal carcinomas tissues can be a new prognostic marker for tumor invasion and patients survival. CDX2 can be easily applied to routine histologic material and is a specific and sensitive immunohistochemical marker in the differential diagnosis of primary versus metastatic carcinomas in the liver(CDX2-positive supports intestinal origin).