Last update:
12-Jun-2001

Arch Hellen Med, 17(6), November-December 2000, 584-592

ORIGINAL PAPER

Immunolocalization of cytokeratin 8 on epoxy resin semithin sections
of infiltrating ductal breast carcinomas

S. HAVAKI,¹ I. BALTAZIS-VOLOUDAKIS,² U. DAFNI,³
N. GOUTAS,¹ D.L. ARVANITIS,⁴ Ch. KITTAS,¹ E. MARINOS^1
1Laboratory of Histology and Embryology, Medical School, University of Athens,
²Department of Electron Microscopy and Cell Biology, Research Center of Oncology “G. Papanikolaou”, “Saint Savas” Anticancer Hospital,
³Department of Public Health, Faculty of Nursing, University of Athens,
⁴Department of Anatomy, Histology and Embryology, Medical School of Larissa, University of Thessaly, Greece

OBJECTIVE Cytokeratins belong to the intermediate filament family of the epithelial cells. The cytokeratin class expressed in an epithelial cell is cell specific. Cytokeratin 8 (CK8) is present in simple epithelia, such as mammary gland duct cells, and in related neoplasms. CK8 may be implicated in the promotion of breast cancer cell invasiveness in vitro. It is immunolocalized at the outer phase of the cellular membrane of breast cancer cells and is also released into the culture medium; the precise distribution and function of CK8 in vivo has not yet been elucidated. The purpose of this study was the immunolocalization of CK8, under the light microscope, on epoxy resin semithin sections of infiltrating ductal breast carcinomas. The role of CK8 as a prognostic factor was also investigated in infiltrating ductal breast carcinomas.
METHOD Nine cases of infiltrating ductal breast carcinoma and 4 cases of fibroadenoma were studied. In each case, small pieces of fresh tissue were fixed, dehydrated, and embedded in a mixture of epoxy resins. After removal of the epoxy resin polymer in semithin sections of selected cancerous areas, the two step indirect immunoperoxidase method was applied for CK8 immunolocalization. The average optical density in the cytoplasm of the cancer cells, which represents the CK8 expression, was measured by image analysis and the results were analysed statistically.
RESULTS In all cases of infiltrating ductal breast carcinoma, grading of CK8 immunoreaction in the cytoplasm of cancer cells was observed, but in the benign neoplasms the reaction was more intense and uniform. No reaction was observed in negative controls. Statistically significant difference was observed in the average cytoplasmic optical density of the cancer cells, between histological grades II, III and the fibroadenomas, while there was no statistically significant difference between histological grades I, II and III.
CONCLUSIONS The tissue preparation procedure assured successful and specific CK8 immunolocalization on semithin sections of infiltrating ductal breast carcinomas. It is possible that using the same experimental material, the detailed distribution of CK8 can be further studied under the electron microscope. The statistical analysis showed that the value of CK8 expression in assessing tumor grade appears to be limited, where as it can be used as a safe indicator to distinguish malignant from benign tumors.

Key words: Breast, Cytokeratin 8, Ductal infiltrating carcinoma, Immunohistochemistry, Morphometry.