title: Ki-67 immunolabelling index is a prognostic indicator in childhood posterior fossa ependymomas.
abstract: Conventional histological evaluation and subclassification of childhood ependymomas poorly predict their biological behaviour. The Ki-67 labelling index (Ki-67 LI), a measure of growth fraction, correlates with the biological behaviour of several neoplasms, and this retrospective study tested the hypothesis that Ki-67 LI is a prognostic indicator in childhood posterior fossa ependymomas. Immunocytochemistry using an antibody to Ki-67 was undertaken on 5 microns sections of formalin-fixed, paraffin-embedded tissue from 74 cases of childhood (age < 16 years.) posterior fossa ependymoma. A Ki-67 LI was established by counting the proportion of labelled nuclei in more than 1000 cells from several histological fields. Several clinical and histological variables (including Ki-67 LI) potentially associated with survival were entered into univariate and multivariate analyses using a Cox proportional hazards model. Variables that showed a significant and independent association with survival were Ki-67 LI (P < 0.002), whether total surgical resection had been achieved according to operation records (P < 0.03), and whether no adjuvant therapy had been given (P < 0.01). Age, sex, and the presence of necrosis or microvascular proliferation did not correlate with survival. In our defined population of patients with ependymomas, Ki-67 LI is a strong prognostic indicator. We recommend that Ki-67 LI is used in the histological evaluation of childhood posterior fossa ependymomas during trials of novel adjunctive therapies.
authors.affiliation: Department of Pathology, Southampton General Hospital, UK.
authors.forename: L
authors.initials: L
authors.lastname: Bennetto
authors.forename: N
authors.initials: N
authors.lastname: Foreman
authors.forename: B
authors.initials: B
authors.lastname: Harding
authors.forename: R
authors.initials: R
authors.lastname: Hayward
authors.forename: J
authors.initials: J
authors.lastname: Ironside
authors.forename: S
authors.initials: S
authors.lastname: Love
authors.forename: D
authors.initials: D
authors.lastname: Ellison
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003388:Cranial Fossa, Posterior; D004806:Ependymoma / Q000276:immunology* / Q000401:mortality; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D019394:Ki-67 Antigen / Q000032:analysis*; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D019292:Skull Base Neoplasms / Q000276:immunology* / Q000401:mortality; D015996:Survival Rate
chemical_list: D019394:Ki-67 Antigen