Meningiomas often contain steroid hormone receptors, but the correlation of receptor presence with patient outcome or mitotic index is unclear. Intracranial meningiomas from 70 patients (27 males and 43 females, mean age 52.9 + 1.7 years [mean +/- standard error of the mean], range 15-78 years) were evaluated immunocytochemically for female sex hormone receptors using specific monoclonal antibodies. Prognostic correlations were determined using statistical analyses that included clinical and histological variables. Twenty-eight tumors were benign, 27 had atypical features, and 15 were malignant. Thirty tumors were meningotheliomatous, 11 were fibroblastic, 28 were transitional, and one was secretory. Twenty-nine of the 70 primary tumors recurred (mean interval to recurrence 50.1 +/- 10 months). The mean progression-free follow-up period for patients without recurrence was 82.1 +/- 7.7 months. Nuclear staining for the progesterone receptor (PR) was found in 58 cases (83%) and PR status was scored as 0 (0% nuclei positive), 1 (< 1%), 2 (1-9%), 3 (10-49%), or 4 (> 50%). Only six tumors (8.6%) contained nuclear estrogen receptor (ER) staining, which was limited to a small number of nuclei (< 1%). Fisher's exact test (two-tailed) showed an inverse correlation between tumor grade and PR staining score (p < or = 0.001), with 96% of benign and 40% of malignant meningiomas containing PR-positive nuclei. No correlation between age or histological subtype and PR score was detected. Meningiomas from female patients had more PRs (p < or = 0.05). Analysis of variance revealed that the mitotic index (total counts of mitoses per 10 high-power fields) for tumors with 0 PR staining (18 +/- 4.4) was higher (p < or = 0.0001) than for those with PR scores of 1 to 4 (4.3 +/- 1.9, 5.1 +/- 2, 2.2 +/- 0.8, and 1.7 +/- 0.9, respectively). Univariate analysis indicated that the absence of PR, high mitotic index, and higher tumor grade were significant factors for shorter disease-free intervals. Multivariate analysis showed that a three-factor interaction model, with a PR score of 0, mitotic index greater than 6, and malignant tumor grade, was a highly significant predictor (p < or = 0.0001) for worse outcome in patients harboring meningiomas. These data indicate that the presence of PRs, even in a small number of tumor cells, is a favorable prognostic factor for meningiomas.

Glial fibrillary acidic protein was localized at the electron microscope level in the cerebellum of adult mice by indirect immunoperoxidase histology. In confirmation of previous studies at the light microscope level, the antigen was detectable in astrocytes and their processes, but not in neurons or their processes, or in oligodendroglia. Astrocytic processes were stained in white matter, in the granular layer surrounding synaptic glomerular complexes, and in the molecular layer in the form of radially oriented fibers and of sheaths surrounding Purkinje cell dendrites. Astrocytic endfeet impinging on meninges and perivascular membranes were also antigen positive. In astrocytic perikarya and processes, the immunohistochemical reaction product appears both as a diffuse cytoplasmic label and as elongated strands, which by their distribution and frequency could be considered glial filaments.

Mitotic index > 6, proliferating cell nuclear antigen (PCNA) index > 5%, high tumour grade and absence of progesterone receptors (PR) are significant predictors for poor outcome in meningiomas. Since MIB-1 (Ki-67) is a more specific cell proliferation marker, and overexpression of TGF-alpha is also associated with tumour progression, we compared the prognostic significance of these factors with the other indices. Intracranial meningiomas from 21 men and 36 women (age 54.5 +/- 1.7, mean +/- SEM) were classified as 24 benign, 24 atypical and nine malignant. Twenty-one of the 57 tumours recurred (mean interval to recurrence was 57.3 +/- 13.1 months). The mean follow-up period for patients without tumour recurrence was 81.9 +/- 8.7 months. MIB-1 labelling index (LI) was expressed as percentage of labelled nuclei to total tumour nuclei counted in the most densely labelled areas. Analysis of variance revealed significant differences between tumour grades for MIB-1 labelling indices (0.75 +/- 0.21 for benign, 3.2 +/- 0.57 for atypical 6.04 +/- 1.48 for malignant; P < or = 0.0066), and between malignant and non-malignant meningiomas for TGF alpha staining scores (P < or = 0.029). MIB-1 LI also correlated with mitotic and PCNA indices (P < or = 0.0001), but not with age of the patients. Male patients had higher tumour MIB-1 LI than females (P < or = 0.0128). Univariate analysis indicated that MIB-1 LI > 3%, TGF alpha score > 4 (scoring scale 0-5), mitotic index > 6, and negative PR status were significant factors for worse outcome. Higher MIB-1 LI, TGF alpha score and mitotic index as continuous variables were also significant negative predictors. With multivariate analysis, both MIB-1 LI and TGF alpha score remained significant factors when paired with all other variables: TGF alpha or MIB-1 LI, respectively, mitosis, PCNA, tumour grade, PR status, age, sex, postoperative radiation therapy. We conclude that MIB-1 LI and TGF alpha score are important independent prognostic indicators for patients with meningiomas.