Published in Cancer Detection and Prevention 2000; 24(Supplement 1).

Cytokeratin 20 and 7 expression in breast, lung, colorectal and pancreatico-biliary adenocarcinomas: stability and diagnostic utility

T Tot MD PhD

Central Hospital, Dept Pathology and Clinical Cytology, Falun, Sweden,

AIMS: Stability of antigen expression during tumour progression is an essential prerequisite for diagnostic use. We compared expression of Cytokeratins (CKs) 20 and 7 in primary and metastatic adenocarcinomas of the breast, colon, rectum, pancreas and biliary tract to assess the stability of these antigens and compared the phenotype of these tumours to the phenotype of primary lung adenocarcinomas. METHODS: The study material consisted of 125 cases (84 autopsy verified). Representative sections of primary tumours and their metastases were stained in a Ventana system (Tucson, Arizona) using primary antibodies Ks20.8 and OV-TL12/30 (DAKO, Glostrup, Denmark). The immunostaining was evaluated as negative (no staining), focally (less than 10% of the tumour cells) or diffusely positive. RESULTS: Three of 52 breast carcinomas, 24/31 colorectal and 15/42 pancreaticobiliary carcinomas stained positively for CK20. All the cases retained this positivity in the metastases. 31 breast, 1 colorectal and 39 pancreaticobiliary adenocarcinomas expressed CK7. One of the breast carcinomas lost the expression of CK7 while two colorectal cancers gained focal CK7 positivity in their metastases. The typical phenotype of lung and breast carcinomas was the same (CK20-/7+) and differed significantly from the typical phenotype of colorectal carcinomas (CK20+/7-). CONCLUSIONS: CK20 is a stabile antigen which was consequently expressed in the metastases of CK20 positive primary adenocarcinomas. Rarely, adenocarcinomas can gain or lose the expression of CK7 during their metastatic spread. Cytokeratin phenotyping has a role in search for unknown primary tumours discriminating most of the colorectal cancers from breast and lung adenocarcinomas.

KEY WORDS: metastasis.

For more information, contact

Paper presented at the International Symposium on Impact of Biotechnology on Cancer Diagnostic & Prognostic Indicators; Geneva, Switzerland; October 28 - 31, 2000; in the section on metastasis & prevention.