Proliferation in human bladder carcinoma measured by Ki-67 antibody labelling: its potential clinical importance.

Ki-67 is a monoclonal antibody which recognises a human nuclear antigen expressed in proliferating cells. The antibody was used to assess proliferation in primary human bladder tumours from 64 patients. Ki-67 index (the number of Ki-67 positive tumour cells divided by the total number of tumour cells %) was derived from 59 tumours. A wide range of Ki-67 indices were recorded, range 3.0-65.8%, mean 20.2%. The Ki-67 index correlated with known prognostic factors: T stage (P = 0.002) and histological grade (P less than 0.001), early stage disease and more differentiated tumours having lower Ki-67 indices. Patients with invasive disease (21 patients) had significantly higher Ki-67 indices than those with non-invasive disease (P = 0.01). Patients with metastatic disease at presentation (four cases) all had a Ki-67 index of greater than or equal to 29%. Ki-67 antibody staining is a simple technique for assessing the proliferation fraction than can be performed on a small amount of tissue taken at routine biopsy without prior injection of thymidine analogues.