Ki 67 Expression and Its Correlation with the Proliferative Index Measured by Flow Cytometry in Breast Carcinoma

ABSTRACT

PURPOSE: The aim of the present study was to evaluate the clinical utility of Ki 67 labelling index and proliferative indices measured by flow cytometry in breast carcinomas. METHODS: We conducted immunohistochemical assay for Ki 67 and analyzed the DNA content and S-phase fraction by flow cytometry in 113 cases of primary breast carcinomas. Relationship between proliferative indices measured by two method and clinical biological parameters was also analyzed. RESULTS: Ki 67 labelling index than average was increased in 53 tumors (46.9%) and demonstrated a significant correlation with S-phase fraction. Higher Ki 67 labelling index was found in 28 (59.6%) of 47 tumors with high S-phase fraction whereas it was found in only 8 tumors (30.8%) with low S-phase fraction. Concordance between Ki 67 labelling index and S-phase fraction was 63.1% (p=0.017). Tumor with high S-phase fraction had a tendency to have an aneuploid. Ki 67 labelling index correlated significantly with histologic grade (p=0.001) and nuclear grade (p=0.001). An inverse correlation was found between Ki 67 and estrogen receptor expression (p=0.004). CONCLUSION: Ki 67 labelling index significantly correlated with S-phase fraction measured by flow cytometry. Ki 67 labelling index seems to be a clinically useful method because it is rapid, practical and easily performed by immunohistchemical assay.