LI-cadherin and CDX2: Useful Markers in Metastatic Gastrointestinal Adenocarcinoma Cells in Serous Cavity Effusion.

OBJECTIVE: The aim of this study was to investigate the expression and significance of liver-intestine cadherin (LI-cadherin) and CDX2 (caudal-type homeobox transcription factor 2) in cytology specimens of metastatic gastrointestinal adenocarcinoma in serous cavity effusion.

MATERIALS AND METHODS: The serous cavity effusion samples that were suspected of tumor metastasis in the last 5 years were made into paraffin-imbedded cell blocks, a total of 180 cases, including 97 cases of pleural effusion, 78 cases of ascites, and 5 cases of pericardial effusion. The expressions of LI-cadherin and CDX2 were detected by immunohistochemical staining in cell blocks and primary tumor tissues; thereafter, the specificity and sensitivity were analyzed.

RESULTS: The positive expressions of LI-cadherin and CDX2 in 63 cases of gastrointestinal adenocarcinoma cells were 65.1% (41/63), 61.9% (39/63), respectively. Of 11 cases of pancreaticobiliary duct cancers, only one case (9.09%) was weakly positive for LI-cadherin and CDX2 expressions, and 107 cases of non-digestive tract cancers were all negative. In 57 matched-pair samples of cell blocks and primary gastrointestinal adenocarcinoma tissues, the positive expressions of LI-cadherin and CDX2 were 64.9% (37/57), 61.4% (35/57), respectively, in cells, and 82.5% (47/57), and 77.2% (44/57), respectively, in tissues. Positive correlation was observed between the expressions of LI-cadherin and CDX2 in metastatic gastrointestinal adenocarcinoma cells (P<0.05). Both LI-cadherin and CDX2 expressions demonstrated positive correlation in cells with paired cancer tissues (P<0.05). The positive expression reached 80.7% with at least one positive marker in the total cell samples through combined detection of LI-cadherin and CDX2, increased by 15.8% and 19.3% compared with using either of the markers alone.

CONCLUSIONS: Combined use of LI-cadherin and CDX2 can improve the accuracy in the diagnosis of metastatic adenocarcinoma cells in serous cavity effusion and provide some bases of histologic origin because of their high sensitivity and specificity.