Prognostic values of proliferative markers ki-67 and repp86 in breast cancer

Breast cancer is the leading cause of carcinoma death in women. Proper treatment depends on the consideration of molecular biology status of tumor cells, which may determine the patient's treatment and prognosis. To determine the prognostic models for this disease, we evaluated the role of cell proliferation-related antigens including ki-67 (a nuclear antigen, expressed in G1, G2, and M phases of cell cycle) and repp86 (an 86-kDa nuclear protein expressed in S, G2, and M phases of cell cycle) for detection of biologic behavior of breast cancer.

We studied 60 women with grade I and II lymph node-negative and 27 with grade III lymph node-positive breast cancers. The mean follow-up periods for these two groups were 60 and 72 months, respectively. Tumor cell proliferation was measured by immunohistochemical methods with monoclonal antibodies directed against the nuclear antigens ki-67 and repp86.

The ki-67, repp86 labeling indices (percentage of antibody-stained tumor cell nuclei) were not statistically different between the cases and controls of lymph node-negative patients (ki-67 with P = 0.33; repp86 with P = 0.40). The odds ratio (the mean chance of ki-67 labeling index > 10%, repp86 labeling index >10%) in patients with recurrence was 4 (CI = 0.2 - 76.5) for ki-67 and 3.6 (CI = 0.4 - 32.5) for repp86. Both indices were statistically different in lymph node-positive cases and controls (P < 0.0001). The odds ratio in patients with recurrence was 87 (CI = 4 - 18.71) for ki-67 and 71.5 (CI = 5.7 - 899.2) for repp86.

The present study confirms the importance of cell proliferation as a determinant of biologic behavior of breast cancer. Measurement of ki-67 and repp86 labeling indices may be very helpful for physicians to detect high-risk patients and to adopt appropriate procedure such as adjuvant therapy.