Prognostic value of Ki67 index in anaplastic oligodendroglial tumours--a translational study of the European Organization for Research and Treatment of Cancer Brain Tumor Group

Matthias Preusser, Romana Hoeftberger, Adelheid Woehrer, Ellen Gelpi, Mathilde Kouwenhoven, Johan M Kros, Marc Sanson, Ahmed Idbaih, Alba A Brandes, Harald Heinzl, Thierry Gorlia, Johannes A Hainfellner, Martin van den Bent

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

AIMS: To evaluate the prognostic value and clinical utility of Ki67 tumour cell proliferation index in anaplastic oligodendroglial tumours (AOT).

METHODS AND RESULTS: We performed anti-Ki67 immunostaining (MIB-1 antibody) of formalin-fixed and paraffin-embedded tumour tissue specimens of 128 patients with newly diagnosed AOT that were treated in a randomized Phase III trial. Ki67 index was assessed by three independent observers and was correlated to clinical, histopathological and molecular features (including 1p/19q co-deletion, epithelial growth factor receptor gene (EGFR) amplification, isocitrate dehydrogenase (IDH1) mutations, O6-methylguanine-DNA methyltransferase gene (MGMT) promoter methylation, and patient survival times. Intra- and inter-observer agreement of Ki67 index assessment was excellent. Univariable analysis (n = 79) showed that patients with a low Ki67 index had significantly more favourable progression-free survival (PFS) (P-value = 0.004, log-rank test) and overall survival (OS) (P-value = 0.003, log-rank test) than patients with a high Ki67 index, respectively. On multivariable analysis (n = 43), Ki67 index showed no independent association with PFS or OS.

CONCLUSIONS: In AOT the Ki67 index has a strong prognostic impact on univariable analysis, but no independent influence on multivariable analysis. However, further prospective studies including larger numbers of cases and standardized evaluation of Ki67 index in conjunction with other relevant prognostic parameters are needed to draw definitive conclusions.

Original languageEnglish
Pages (from-to)885-94
Number of pages10
JournalHistopathology
Volume60
Issue number6
DOIs
Publication statusPublished - May 2012

Cite this