Two epithelial cell types, the inner glandular and the outer myoepithelial cells, form the current paradigm of breast pathology. A third cell type characterized by K5/14 positvity has been demonstrated in benign, but not in most malignant cases. Methods: We used computer-assisted double labelling techniques for visualization of specific differentiation markers for glandular (K8/18/19) and myoepithelial cells (sm-actin, calponin)and basal keratins 5/6. In total, 10 samples of normal breast tissue, 12 cases of ductal hyperplasia, usual type, and 17 cases of atypical ductal hyperplasia/ductal carcinoma in situ were examined. Findings: In normal breast tissue the existence of K5/6+ progenitor cells, differentiated glandular (K8/18/19+) and myoepithelial cells (sm-actin+)could be established. Furthermore we found intermediate cells expressing either K5/6 and K8/18/19 or K5/6 and sm-actin. The same range of cells was found in all the cases of ductal hyperplasia, usual type. In contrast, sixteen of the ADH and DCIS cases displayed a purely glandular phenotype. Conclusion: We conclude that in normal breast tissue K5/14-positive common progenitor (adult stem) cells give rise to both glandular (K8/18/19+) and myoepithelial cells (sm-actin+, calponin+) via intermediate cells (either K5/6+ , K8/18/19+ or K5/6+, sma-actin+). Ductal hyperplasia consequently is a progenitor (stem) cell-derived lesion, in which the two cell lineages are preserved, whereas ADH/DCIS apparantly evolves from glandularly differentiated cells. Our data point the way towards a new cell biological model that applies to the normal breast and proliferative lesions alike.
|Original language||English (US)|
|Number of pages||1|
|Journal||Breast Cancer Research and Treatment|
|State||Published - Jan 1 2001|
ASJC Scopus subject areas
- Cancer Research