Breast Center Pathology Laboratory
SERVICES/RESOURCES - CLINICAL
Prognostic Biomarkers - Ki-67 Proliferation Index
Indications for use
Proliferation index is an important prognostic factor in breast cancer.
The Ki-67 protein is expressed in all phases of the cell cycle except
G0 and serves as a good marker for proliferation. Studies that have
evaluated proliferation index by Ki-67 IHC in breast cancer have
shown a significant correlation between high proliferation rates
and shorter disease free and overall survival(1-4).
Scoring/Interpretation
The Ki-67 proliferation index is assessed by point counting 500 to
1000 cells, and is reported as percent positive cells. The cut-off
to define a high Ki-67 proliferation index is not well-established
or universally agreed upon. In our laboratory, we use 20% positive
cells to define “positive” (i.e. high risk) based on
the results of studies we feel are currently the best available in
the medical literature (1, 2).
Selected Bibliography
1. Veronese SM, Maisano C, Scibilia J. Comparative prognostic
value of Ki-67 and MIB-1 proliferation indices in breast cancer. Anticancer
Res 1995;15(6B):2717-22.
2. Seshadri R, Leong AS, McCaul K, Firgaira FA, Setlur V, Horsfall DJ. Relationship between p53 gene abnormalities and other tumour characteristics in breast-cancer prognosis. Int J Cancer 1996;69(2):135-41.
3. Biesterfeld S, Kluppel D, Koch R, Schneider S, Steinhagen G, Mihalcea AM, et al. Rapid and prognostically valid quantification of immunohistochemical reactions by immunohistometry of the most positive tumour focus. A prospective follow-up study on breast cancer using antibodies against MIB-1, PCNA, ER, and PR. J Pathol 1998;185(1):25-31.
4. Liu S, Edgerton SM, Moore DH, 2nd, Thor AD. Measures of cell turnover (proliferation and apoptosis) and their association with survival in breast cancer. Clin Cancer Res 2001;7(6):1716-23.