Prognostic Significance of Ki-67 Proliferation Index in Supratentorial Fibrillary Astrocytic Neoplasms

Hereditary gingival fibromatosis and expression of Ki-67 antigen: a case report

BACKGROUND

Hereditary gingival fibromatosis (HGF) is a fibrotic enlargement of the gingiva. The mechanism that leads to the accumulation of abnormal amounts of gingival tissue in HGF is still unknown. The aim of this report was to present the clinical and histopathologic characteristics of a patient with gingival fibromatosis and to evaluate the proliferation of HGF fibroblasts.

METHODS

We examined the proliferation rate of fibroblasts in this case by using Ki-67 immunohistochemical staining and compared the rate to fibroblasts of non-fibromatosis gingival tissues from 5 healthy patients serving as controls.

RESULTS

There were no Ki-67-positive cells in the lesional tissue, and the control gingiva revealed no immunostaining. The number of Ki-67 antigen-positive epithelial cell nuclei was observed to be low in the basal cell layers of hyperplastic gingival epithelia, similar to the control group.

CONCLUSIONS

In the present case, there was no increase in the proliferation rate of lesional fibroblasts observed by Ki-67 immunohistochemical staining as a proliferation marker; only the epithelium was stained. It seems likely that the underlying mechanism of HGF may be an increase in the biosynthesis of collagen and glycosaminoglycans rather than cell proliferation.

De novo cerebellar medulloblastoma in a 26-year recurrence-free case of temporal glioblastoma multiforme

The authors describe a patient who survived 26 years after resection of a right temporal glioblastoma multiforme (GBM) without signs of tumor recurrence. Preoperative emergency angiography demonstrated a hypovascular mass localized in the right temporal lobe with right-to-left shift of the vascular structures. At surgery, the tumor had cystic and solid components localized in the lateral occipitotemporal gyrus, reaching the posterolateral wall of the inferior horn of the right lateral ventricle and extending to the trigone and posterior horn. The initial pathological diagnosis of a GBM was reviewed and confirmed throughout the follow-up period. Twenty-six years after surgery and subsequent radiosurgery, the patient underwent resection of a medulloblastoma localized in the right cerebellum as well as stereotactic biopsy sampling of tissue at the original GBM site. Neither radiological nor histological evidence of recurrence of the GBM could be documented. The intraoperative, histological, and radiological findings are described.

MIB-1 (Ki-67) index and transforming growth factor-alpha (TGF alpha) immunoreactivity are significant prognostic predictors for meningiomas

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.