Cell proliferation in serial biopsies through human malignant brain tumours: Measurement using Ki67 antibody labelling

Abstract

Cell proliferation was assessed in brain tumours using the monoclonal antibody Ki67 which recognizes a nuclear antigen expressed by proliferating cells. Using a novel stereotactic biopsy procedure, serial 1 cm biopsies were taken along a trajectory through six malignant brain turnours. Specimens were also obtained from 10 other brain tumours during conventional surgery. The percentage of Ki67 positive cells was determined as a fraction of the total number of tumour cells present. The Ki67 index for anaplastic astrocytomas and glioblastomas was significantly higher (Ki67 index range 11–18%) than that for benign or low grade turnours. Significant variation in proliferation was measured along the biopsy track through individual turnours (e.g. 0–12.3%) which correlated well with histological appearance. The Ki67 indices of normal brain were very low. In general the Ki67 indices increased with increasing histological grade and also appear to be a useful indicator of the active tumour volume and margin. This method provides spatial information about tumour proliferation which may be used to decide between different treatments and relate to prognosis.

Key Words:

• Cell proliferation
• Ki67 index
• stereotactic biopsy
• malignant glioma