Immunohistochemical assessment of Ki67 with antibodies SP6 and MIB1 in primary breast cancer: a comparison of prognostic value and reproducibility.

Aims: To compare SP6 and MIB1 antibodies for assessment of Ki67 in primary breast cancer with regard to prognostic value and reproducibility.

Methods And Results: A cohort of 237 premenopausal women with node-negative breast cancer, mainly (87%) not treated with adjuvant systemic therapy, was used. Assessment of Ki67 (SP6 and MIB1) was performed on tissue microarray by three different investigators.

The prognostic value of mitotic activity index (MAI), phosphohistone H3 (PPH3), cyclin B1, cyclin A, and Ki67, alone and in combinations, in node-negative premenopausal breast cancer.

Proliferation, either as the main common denominator in genetic profiles, or in the form of single factors such as Ki67, is recommended for clinical use especially in estrogen receptor-positive (ER) patients. However, due to high costs of genetic profiles and lack of reproducibility for Ki67, studies on other proliferation factors are warranted. The aim of the present study was to evaluate the prognostic value of the proliferation factors mitotic activity index (MAI), phosphohistone H3 (PPH3), cyclin B1, cyclin A and Ki67, alone and in combinations.