PROGNOSTICATION OF ASTROCYTOMA PATIENT SURVIVAL BY KI-67 (MIB-1), PCNA, AND S-PHASE FRACTION USING ARCHIVAL PARAFFIN-EMBEDDED SAMPLES

The prognostic power of three proliferation estimation methods, Ki-67 (MIB-1) and PCNA immunohistochemistry, and flow cytometry (S-phase and S+G2/M fractions, respectively), were evaluated in 50 cases of astroc ytoma. Each proliferation index showed a strong association with the g rade of malignancy (grades I-IV). The MIB-1 labelling index (LI) provi ded additional information, as it could be used for the discrimination of grade II and grade III astrocytomas (P=0.0357). All three prolifer ation estimation methods also had strong prognostic potential (MIB-1 L I: P<0.0001; PCNA Li: P<0.0001; S-phase: P=0.0004; S+G2/M: P=0.0124). According to the receiver operating characteristics (ROC) curve, the M IB-1 LI showed generally the best sensitivity and specificity in placi ng the patients correctly into groups of survivors and non-survivors, which was further confirmed in the multivariate analysis. Only 4 per c ent of the patients having high MIB-1 scores (>15.3 per cent) were ali ve after 2-years' follow-up. In contrast, 72 per cent of patients with tumours of low proliferation activity survived. It appears that Ki-67 (MIB-1) immunolabelling using archival paraffin-embedded samples is o f value in predicting prognosis in astrocytic tumours.