MIB-1 proliferation index correlates with survival in pleural malignant mesothelioma

Aims: The purpose of this study was to establish whether the cell prolifera tion index assessed by the monoclonal antibody MIB-1 would correlate with s urvival in pleural malignant mesothelioma. Methods and results: We studied a series of seven long-term survivors with pleural malignant mesothelioma and a group of control cases with short-term survival. All cases showed MIB-1 positive cells, and labelling indices wer e expressed as percentage of cells with positive nuclear immunostaining by randomly counting 1000 tumour cells. A statistically significant difference was found between MIB-1 values in the long-term survival group and the con trol cases with short-term survival. Conclusions: Our results indicate that the differences in biological behavi our of malignant mesothelioma in long-term and short-term survivors may be explained in part by differences in tumour growth fraction and that prolife ration index could represent an important prognostic parameter for this tum our.