An immunohistological method for estimating cell growth fractions in rapid histopathological diagnosis during surgery

In the past, it has been impossible to carry out immunohistological staining as part of a rapid histopathological diagnosis during surgery because the available methods were too time‐consuming. The present report introduces a rapid indirect immunoperoxidase method that requires only 10–12 min. Thus, the immunological characterization of tumour cells may now be applied as an additional parameter for histopathological diagnosis during surgery. In this first attempt, the monoclonal antibody Ki‐67, which reacts with a human nuclear antigen present in proliferating cells and absent in quiescent cells, was applied with a new immunostaining method and the results were compared with those obtained by the more time‐consuming routine immunohistological method. There was no significant difference between the percentages of Ki‐67‐positive cells determined with the two methods in normal or neoplastic human tissues. Since knowledge of the growth rate of a malignant tumour may be of prognostic and/or therapeutic value in individual cases, it might be useful to routinely apply this new approach for histopathological diagnosis during surgery.