Prognostic value of the proliferation-related antigen Ki-67 in oligodendrogliomas.

Abstract

In various neoplasms expression of the proliferation-related Ki-67 antigen has successfully been linked with parameters of progression of disease. While a definite grading scheme for oligodendrogliomas has still not been agreed upon, any parameter of tumor proliferation that might be helpful in predicting clinical outcome should be evaluated. The expression of the proliferation related nuclear antigen Ki-67 (MIB-1 monoclonal antibody) was investigated in a series of 108 verified oligodendrogliomas, and the percentages of immunoreactive cells were compared with the survival times of the patients. Using multivariate analysis the prognostic value of MIB-1 labeling index (LI) was assessed taking into account age, tumor site, grade, and mitotic index (MI). Patient's age, tumor site, grading according to the grading scheme by Smith, MI and MIB-1 LI were all significantly related to survival. Whereas in a multivariate analysis, age, site, grade and MIB-1 LI had independent prognostic significance, MI failed to add significant prognostic value. The MIB-1 LI is an important addition to histopathologic grading for predicting clinical outcome of patients with oligodendrogliomas. The MIB-1 LI adds prognostic information independent of patient's age, tumor site and grade. The MI might be incorporated into a grading scheme for oligodendrogliomas, but is not by itself an additional prognosticator.