Abstract

OBJECTIVE

Analyzing the expression of cytokeratin 7 and 20 plays an important role in discriminating primary and metastatic liver tumors. The cytokeratin 7/20 phenotype of tumors is one of the most helpful for differential diagnosis.

METHODS

Seventy-two liver specimens (59 resection material and 13 core needle biopsy) consisting of 25 intrahepatic cholangiocarcinoma, 28 colorectal adenocarcinoma metastases, 13 pancreaticobiliary adenocarcinoma, 4 gastric adenocarcinoma metastases, 1 lung adenocarcinoma metastasis, 1 breast carcinoma metastasis were examined. Primary tumor localization could be established in all. Immunohistochemical algorithm with two monoclonal cytokeratin antibodies, cytokeratin 20 and cytokeratin 7 was tested on 72 tumor sections.

RESULTS

The positivity rate and intensity of immunostaining were evaluated. Cytokeratin 7(+)/20(-) phenotype was seen in 76% (19 of 25) of intrahepatic cholangiocarcinoma with 89% specifity, 76% sensitivity and 79% positive predictive value. The cytokeratin 7(+)/20(+) phenotype was detected in 69% (9 of 13) of pancreaticobiliary adenocarcinomas with 76.3% specifity, 69.2% sensitivity, 39.1% positive predictive value. The cytokeratin 7(-)/20(+) phenotype was observed in 82% (23 of 28) of colorectal adenocarcinoma metastases (97.7% specifity, 82.1% sensitivity, 95.8% positive predictive value).

CONCLUSION

In conclusion, our study shows that cytokeratin 7/20 phenotype has diagnostic value in differential diagnosis of primary and metastatic liver tumors.