Evaluation of Ki-67 monoclonal antibody as prognostic indicator for prostatic carcinoma.

Prostate tissue containing either primary adenocarcinoma (45 patients) or benign hyperplasia (15 patients) was immunostained with the monoclonal antibody Ki-67, which recognises a human nuclear antigen expressed by human cycling cells. The percentage of cells staining positive was considered a measure of proliferation. This derived Ki-67 index was higher for carcinomas than for hyperplastic glands. Within the group of carcinomas, Ki-67 indices in patients with metastatic disease were significantly higher than in those without and there was a trend towards increasing Ki-67 indices with increasing Gleason grade. When patients with prostate cancer were prospectively followed up, the Ki-67 index did not predict either disease progression or hormone responsiveness. Ki-67 immunostaining may define a group of patients with prostate cancer of poor prognosis.