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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A104
In general, progression of pre-invasive to invasive lesions goes hand in hand
with a net increase in the number of cells, which may be caused by increased
proliferation or decreased cell death. In this study, we determined the
mitotic and apoptotic index through a spectrum of pre-invasive ductal breast
lesions to invasive carcinoma in search of disturbances in the proliferation
/cell death balance in breast carcinogenesis. Seventy two pre-invasive ductal
breast lesions and 155 invasive breast carcinomas were used. The number of
mitotic (MI) and apoptotic (AI) cells were microscopically counted in
hematoxylin and eosin stained sections, and the ratio of the values of MI and
AI was calculated (M/A index). A distinction was made between well differentiated
and poorly differentiated breast lesions, to arrive at two plausible
progression models for breast carcinogenesis. For the well differentiated
breast lesions, the MI was rather equal for hyperplasias and well differentiated
DCIS, but increased 5-fold from DCIS to well differentiated invasive
carcinoma. The AI remained in the same range, resulting in a 3.5-fold increase
of the M/A index. For the poorly differentiated breast lesions, a significant
increase in MI and AI was found from hyperplasia to poorly differentiated
DCIS. From DCIS to poorly differentiated invasive carcinoma, the MI increased
and the AI decreased, resulting in a 2.5-fold increase of the M/A index.
In conclusion, transition from well differentiated pre-invasive to well
differentiated invasive carcinoma is accompanied by an increase of cell
proliferation rather than decrease in apoptosis. In contrast, in poorly
differentiated breast lesions, decreased apoptosis seems to be equally
important as increased proliferation in carcinogenesis and progression.
BALANCE OF CELL PROLIFERATION AND APOPTOSIS IN BREAST CARCINOGENESIS
Mommers ECM, Van Diest PJ, Leonhart AM, Meijer CJLM, Baak JPA,br>
Department of Pathology, Free University Hospital, Amsterdam, Netherlands