ABSTRACT
Objective To investigate the expressions of guanylyl cyclase-c(GC-C) and caudal-type homeobox transcription factor 2 (CDX2) in human gastric tissues and precursor lesions and its significance. Methods The cancerous and paracancerous (5 cm from cancer lesion )samples from 30 cases of gastric cancer and 32 samples including 23 intestinal metaplasia and 9 dysplasia were collected. The mRNA expressions of GC-C and CDX-2 were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and proteins of GC-C and CDX-2 were measured by using Western blot and immunofluorescence methods. Results The mRNA expressions of GC-C and CDX-2 were absent in paracancerous tissues, but were 66.7% and 63.3% in cancerous tissues, respectively(P=0. 000). The Western blot indicated that expressions of GC-C and CDX-2 were 19/30 and 17/30 in cancerous tissues, but absent in paracancerous tissues(P=0. 000). The immunofluorescence examination revealed that GC-C and CDX-2 expressions were 39.1% and 39.1% in intestinal metaplasia, 55.6% and 55.6% in dysplasia, and 56.7% and 60.0% in cancerous tissues, respectively, but absent in paracancerous tissues. Moreover, expressions of GC-C and CDX-2 showed a statistical difference between intestinal-type and diffuse-type of gastric cancer (P＜ 0.05) ,but had no correlation with age, sex, size of the lesion, clinical stage and lymphnode metastasis. The positive correlation was found in expressions of GC-C and CDX2 between intestinal metaplasia and cancerous tissues(r=0. 4524 and 0. 3845, P= 0. 037 and 0. 0408, respectively). Conclusions The over expressions of GC-C and CDX2 in human gastric cancer is associated with precursor lesions and may play an important role in the carcinogenesis of gastric cancer. The examination of GC-C and CDX2 expressions will be helpful in diagnosing gastric cancer and precursor lesions.
ABSTRACT
Distinguishing primary ovarian carcinoma from metastatic carcinoma to the ovary is often difficult by histologic examination alone. Recently an immunohistochemical marker CDX-2 was found to be of considerable diagnostic value in establishing the gastrointestinal origin of metastatic tumors. The aim of this study was to determine whether CDX-2 can distinguish between these malignancies. Paraffin-embedded tissue sections from 57 primary ovarian tumors and 40 metastatic tumors to the ovary were immunostained for CDX-2, and results were compared to the ancillary immunohistochemical results for CK7/CK20, CEA, CA125, and her-2/neu. CDX-2 immunoreactivity was observed in most of metastatic carcinomas with colorectal (91%) and appendiceal (100%) origin, however CDX-2 was negative in all primary ovarian carcinomas, except for the mucinous subtype. Almost all primary ovarian carcinomas including the mucinous subtype showed diffuse and strong immunoexpression for CK7. CEA and CA125 were mainly found in metastatic and primary ovarian carcinoma, respectively. Her-2/neu overexpression was only noted in a small proportion of primary and metastatic ovarian carcinomas. These results suggest that CDX-2 is very useful immunohistochemical marker for distinguishing metastatic colorectal carcinoma to the ovary from primary ovarian carcinoma, including the mucinous subtype. Furthermore, combination with CDX-2 and CK7 strengthen the differential diagnosis between these tumors.