PROGNOSTIC-SIGNIFICANCE OF DNA-PLOIDY AND PROLIFERATIVE INDEX (MIB-1 INDEX) IN GASTROINTESTINAL STROMAL TUMORS

The DNA content and proliferative index of 61 gastrointestinal stromal tumors (GIST) were measured by image analysis and correlated with the lesion's clinicopathological features and patient's survival, DNA ana lysis was performed on cytospin single-cell preparations obtained from the paraffin-embedded tissue blocks. MIB-1 tvas the proliferation mar ker used on paraffin sections. DNA aneuploidy was detected in 12 tumor s (18%), and high MIB-1 index (>22%) in 12 lesions (18%), DNA aneuploi dy and high MIB-1 index statistically correlated with high mitotic rat e (greater than or equal to 5 x 10 high-power field [HPF]) (P < .001) and with the presence of necrosis (P < .05). The patient's survival wa s significantly correlated with DNA ploidy (P < .01), MIB-1 index (P < .00001), mitotic rate (P < .00001), presence of necrosis (P < .0001), and size of the tumor (P < .01), Multivariate regression analysis sho wed that only MIB-1 index tvas an independent parameter in predicting the clinical outcome for patients with GIST, The mitotic rate was the only other independent prognostic factor when MIB-1 index was not allo wed to enter the model. Copyright (C) 1997 by W.B. Saunders Company.