DNA topoisomerase IIalpha expression correlates with cell proliferation but not with recurrence in intracranial meningiomas.

Aims: To assess the value of topoisomerase IIalpha (TopoIIalpha) as a novel proliferation-associated molecule, by correlating its immunohistochemical expression with Ki67 (MIB-1), cell proliferating cell nuclear antigen (PCNA) and mitotic index in meningiomas. Furthermore, to investigate its relation to standard clinicopathological parameters and patients' outcome.

Methods And Results: This retrospective study comprised a consecutive series of 57 patients with primary intracranial benign and atypical meningiomas. Six tumours recurred (10.5%) following complete surgical resection, within a follow-up period ranging from 21 to 108 months (median 60 months). Archival formalin-fixed paraffin-embedded sections were stained with standard immunohistochemical methods. The lower proliferation indices were obtained with TopoIIalpha and the higher ones with PCNA. TopoIIalpha labelling index (LI) ranged from 0.1% to 10% (median 0.5%) and, along with Ki67 and PCNA LI, increased with malignancy grade (P=0.049, P=0.045 and P < 0.001, respectively), displaying though a significant overlapping between grades. A significant positive correlation was shown between TopoIIalpha and Ki67 (P < 0.001) or PCNA (P=0.032). In univariate and multivariate survival analysis, TopoIIalpha failed to predict meningioma recurrence and did not affect disease-free survival. Only tumour size and Ki67 LI provided significant prognostic information in this regard.

Conclusions: TopoIIalpha expression may be useful as a novel proliferation marker in meningiomas, presenting several advantages over the markers currently in use, notably providing a better estimate of the number of cycling cells and a more uniform nuclear staining pattern. However, it fails to discriminate between benign and atypical neoplasms and does not provide prognostic information beyond that obtained by Ki67.