RT Journal Article SR Electronic T1 Ultrarapid Ki-67 immunostaining in frozen section interpretation of gliomas JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 263 OP 268 DO 10.1136/jcp.2004.018606 VO 58 IS 3 A1 Haapasalo, J A1 Mennander, A A1 Helen, P A1 Haapasalo, H A1 Isola, J YR 2005 UL http://jcp.bmj.com/content/58/3/263.abstract AB Background: Astrocytic tumours, the most common gliomas, are often classified intraoperatively using standard morphological staining. The final diagnosis and grading of gliomas on paraffin wax sections is often assisted by Ki-67 immunohistochemistry, but standard immunostaining protocols take too long to be used intraoperatively. Aims: To investigate a new rapid Ki-67 immunohistochemical test for its use in an intraoperative setting. Methods: The new Ki-67 immunostaining (Ultrarapid-Ki67®) method on frozen sections can be carried out in 10 minutes. Thirty four pilocytic and diffuse astrocytomas were immunostained by rapid Ki-67 and results were compared with corresponding MIB-1 staining, histological grading, and prognosis. Results: The staining protocol was practical to perform and the results were morphologically and quantitatively indistinguishable from those after immunostaining with MIB-1, an antibody recognising Ki-67 in paraffin wax embedded tissue. A comparison of Ultrarapid-Ki67 and MIB-1 immunostaining of paraffin wax sections showed almost identical quantitative correlation in astrocytic gliomas (r = 0.916; p<0.001). The Ultrarapid-Ki67 indices (percentage of positive cells) of low grade (I/II) astrocytomas ranged from 0% to 6.1%, whereas those of representative high grade (III/IV) tumours were significantly higher (range, 5.6–45%; p<0.001). The best prognostic cutoff point for Ultrarapid-Ki67 was 7.5%, which divided diffuse grade II–IV astrocytomas into significantly differing subsets (p = 0.0008). Conclusion: Ultrarapid-Ki67 immunostaining is a useful adjunct to morphological diagnosis and grading of astrocytic tumours, and as a fast test (∼10 minutes for staining plus three to four minutes for scoring), it could be used in routine intraoperative diagnosis of gliomas and other neoplastic diseases.