Although various
DNA flow-cytometric studies have been performed on
meningiomas, the role of
DNA ploidy and the S-phase fraction (SPF) in predicting
biological tumor behavior remains unresolved. Discrepant results in earlier studies might be due to different preparing, staining and measuring techniques; different quality standards; and lack of sophisticated computer software. In this study, high-resolution
DNA flow cytometry using the
DNA-specific
dye DAPI (4', 6'-diamidino-2-phenylindol) was performed on stored frozen tissue from 128 microsurgically resected
meningiomas and 7
hemangiopericytomas, including 17 recurrent
meningiomas and 4 recurrent
hemangiopericytomas. The computer software Multicycle 2.5 was used to determine the ploidy level and to perform cell-cycle analysis.
DNA aneuploidy and SPF were significantly higher in atypical, anaplastic and recurrent
meningiomas and correlated well with histopathological features such as focal
necrosis, infiltration of dura mater and mitotic activity. Among 128
meningiomas, 42 had additional
DNA aneuploid stem lines. No association between hypo- and hyperploidy and either histological subtype or clinical outcome was found. In 7
hemangiopericytomas, SPF was significantly higher compared to the benign
meningioma group, while only 1
tumor was
aneuploid. In all 42
DNA aneuploid tumors, cell-cycle analysis was performed separately for the euploid and
aneuploid stem lines. The proliferation parameters (SPF, G2/M phase) were significantly higher in the
DNA aneuploid stem lines.
DNA ploidy and SPF are thus useful indicators of different
biological behavior within identical histological subgroups in
meningiomas.