Cell turnover in apocrine metaplasia of the human mammary gland epithelium: apoptosis, proliferation, and immunohistochemical detection of Bcl-2, Bax, EGFR, and c-erbB2 gene products.
Apocrine metaplasia is considered to be a benign lesion of human mammary epithelium. However, it is not known how apocrine differentiation develops, and whether there is a relationship with particular subtypes of mammary carcinoma. In order to investigate cell turnover in apocrine metaplasia, apoptosis was detected by terminal transferase nick-end-labelling, and Ki-67 was used as proliferation marker. Bcl-2, Bax, epidermal growth factor receptor (EGFR), and c-erbB2-encoded protein were detected by immunohistochemistry. The proliferative activity was low (<1%). Frequency and intraepithelial localization of apoptotic cells resembled those of normal mammary epithelium. Bax immunostaining was inconstant and weak, and Bcl-2 was not detectable in apocrine metaplasia. Immunoreactivity of the c-erbB2 gene product was membrane-bound and showed a moderate to strong intensity, whereas staining for EGFR was weak and inconsistent. When compared with normal breast epithelium, apocrine metaplasia shows a regular cell turnover at a low rate, although the expression patterns of regulatory proteins are clearly altered. Our data suggest that changes in the expression of Bcl-2 or c-erbB2 protein do not result in a significant imbalance of apoptosis and proliferation, and thus should not be interpreted as indicator for increased risk of neoplastic transformation.
Feuerhake
F
F
Department of Neuropathology, University of Freiburg, Germany. feuerhak@nz11.ukl.uni-freiburg.de
Unterberger
P
P
Höfter
E A
EA
D017209:Apoptosis / Q000502:physiology*; D001940:Breast / Q000473:pathology* / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D004848:Epithelium / Q000473:pathology*; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000032:analysis; D008679:Metaplasia; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis
D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2