Ki-67 immunoreactivity in meningiomas--determination of the proliferative potential of meningiomas using the monoclonal antibody Ki-67.

The proliferative potential of 66 human intracranial meningiomas (15 benign, 15 atypical, 15 recurrent, 13 bone-invasive, and 8 brain-invasive) was investigated by means of immunohisto-chemistry using the monoclonal antibody Ki-67. This antibody recognizes a nuclear antigen present in human cells during all active phases of the cell cycle, but absent in the resting phase. The purpose of this retrospective study was to estimate the Ki-67-labelling index (L.I.) and see if this index could help discriminate between the different groups of meningiomas. Our results demonstrated that L.I. could discriminate between benign, bone-invasive/atypical, brain-invasive meningiomas. In the recurrent group of meningiomas the L.I. decreased from the first to the last operation. We conclude that estimation of L.I. at the time of the operation might help identify meningiomas with a high growth potential and thereby give valuable information concerning the prognosis.