Abstract

PURPOSE
This study was performed to determine the expressions of cytokeratin 7 and cytokeratin 20 in epithelial neoplasms, and to investigate their potential role in the differential diagnosis of carcinomas of various organs.
MATERIALS AND METHODS
We investigated 91 various cases of primary and metastatic cancers, using a panel of commercially available monoclonal antibodies against cytokeratins 7 and 20 (CK7 and CK20), by immunohistochemistryand an avidin-biotin immunoperoxidase technique. The specimens were formalin-fixed and paraffin- embedded, and examined using 4micrometer thick serial sections.
RESULTS
The expression of CK7 was seen in the majority of carcinoma cases, including transitional cell carcinomas (100%), pulmonary adenocarcinomas (100%), ovarian serous adenocarcinomas (100%), cholangiocarcinomas (70%), colonic adenocarcinomas (64.29%) and invasive ductal carcinomas (60%). The expression of CK20 was seen in the majority of colorectal carcinomas cases (85.72%), but was virtually absent in pulmonary adenocarcinomas (0%), uterine cervical carcinomas (0%), ovarian carcinomas (0%), prostatic adenocarcinomas (0%), adenocarcinomas of the gall bladder (0%) and cholangiocarcinomas (12.5%).
CONCLUSION
In the all cases investigated, either CK7 or CK20 immunophenotypes were conserved in the tumor cells of primary tumors and in those of the corresponding metastatic lesions. It is suggested that CK7/CK20 immunophenotyping, in metastatic carcinomas of an unknown origin, maybe useful in the determination of the primary site of the metastasis.

• Keywords: Carcinoma;Cytokeratin 7;Cytokeratin 20;Immunohistochemistry