PROGNOSTIC-SIGNIFICANCE OF 2 PROLIFERATIO N-ASSOCIATED FACTORS IN NODE-NEGATIVE BREAST-CANCER - S-PHASE AND MIB1 (KI-67)

Objective: In 90 patients with primary node-negative breast carcinomas we compared the prognostic impact of total S-phase fraction (SPF) and MIB1 proliferation rate (MIB1-PR) after a median follow-up of 34 mont hs (9-72 months). Methods: SPF was determined now cytometrically and M IB1 (Ki-67) immunohistochemically in parallel-cut, paraffin-embedded t issue sections. Results: SPF was significantly correlated to tumor siz e and steroid hormone receptor status, MIBI-PR to grading. In univaria te analysis both SPF and MIB1-PR were significant prognostic factors f or disease-free survival. In multivariate analysis however, S-phase fr action was the only significant prognostic factor when compared to MIB 1-PR, tumor size, steroid hormone receptor status, menopausal status, grading, lymph vessel invasion, and tumor necrosis. Conclusions: In ou r study SPF was of higher prognostic strength and may therefore be bet ter suited for clinical application than MIBI-PR in node-negative brea st cancer.