Detection of proliferating cell nuclear antigen in gliomas and adjacent resection margins

Techniques to assess the proliferative potential of brain tumors

Assessment of brain tumor proliferative potential provides important prognostic information that supplements standard histopathologic grading. Many laboratories rely on mitotic figures to quantify the proliferative potential of brain tumors, but this conventional cellular proliferative index is subject to inter-observer variability and not consistently predictive for low-and high-grade tumors. Recent advancements in technology have made it possible to use proliferative indices as a standard supplement in pathology laboratories. Non-invasive tumor tissue measurements of cell proliferation can be performed using- bromodeoxyuridine labeling index (BrdU LI), flow cytometry (FCM), MIB-1 antibody to the Ki-67 antigen (MIB-1), proliferating cell nuclear antigen (PCNA), and argyrophilic nucleolar organizing regions (AgNOR). Each of these assays has been described in the literature with respect to its ability to predict tumor grade or outcome. At the present time MIB-1 and AgNOR are the simplest and most reliable of these techniques. In addition, advances in our understanding of the genetic alterations associated with proliferation promise to provide more specific markers of proliferative potential. Beyond the pathology laboratory, radiographic studies such as positron emission tomography (PET), single photon emission computed tomography (SPECT), and most recently magnetic resonance spectroscopy (MRS) have been used as follow-up measures, assessing response to treatment and tumor recurrence, rather than as predictors of response to treatment. These radiographic tools, however, have the potential to provide an assessment of tumor proliferation without the need for invasive measures. In this article, we present a review of the current techniques utilized to understand the proliferative potential of brain tumors.

Possible involvement of Fas system in the induction of apoptosis in human astrocytic brain tumors

1. For a better understanding of the biological features of astrocytic tumors, we investigated apoptosis and its pathway, especially in the interaction between Fas and Fas ligand (FasL). 2. We examined the presence of apoptosis in human astrocytic brain tumors by terminal deoxynucleotidyl transferase (TdT)-mediated d-UTP-biotin nick end labeling (TUNEL) and then apoptotic index (AI) was calculated. We also examined the distribution of Fas and FasL-positive tumor cells immunohistochemically. Labeling index (LI) for Fas and FasL was calculated as Fas-LI and FasL-LI, respectively, and compared to AI. 3. Tumor cells expressing both Fas and FasL were TUNEL positive. Such cells were distributed sparsely in low-grade astrocytomas, but focally in glioblastomas. There was a close correlation among AI, Fas-LI, and FasL-LI, and astrocytic tumors with higher Al were associated with a longer survival time than that with lower Al. 4. It was concluded that the Fas system may be involved in the apoptosis of astrocytic tumors, and Al can be a useful parameter for assessing prognosis of astrocytic tumors.

Expression of the proliferating cell nuclear antigen and clinicopathological features in intracranial meningiomas

PC10, a monoclonal antibody (mAb) to proliferating cell nuclear antigen (PCNA) is known to show immunoreactivity in paraffin-embedded specimens. The authors present the relation between PCNA expression and clinicopathological features in 38 intracranial meningiomas. PCNA scores were obtained by immunohistochemical staining of the paraffin-embedded sections using a streptavidin-biotin immunoperoxidase method with PC10 mAb. Univariate analysis showed that high PC10 scores were associated with old age (> or = 50 years old), male, recurrent tumours, and meningothelial type. However, these high scores did not reach a statistical significance (P> 0.05). PC10 scores of the basal meningioma tended to be higher than that of the hemispheric meningioma (P< 0.05). The staining intensity of PCNA was also markedly increased in basal meningiomas. It is suggested that the proliferative potential is higher in basal meningiomas than in hemispheric meningiomas. Moreover, these results could reflect high recurrence and difficulty in management of the skull base meningiomas.

Immunohistochemical staining of DNA topoisomerase IIalpha in human gliomas

OBJECT

The enzyme DNA topoisomerase IIalpha (Topo IIalpha) was tested as a measure of cell proliferation in gliomas.

METHODS

Immunostaining for the Topo IIalpha and for the Ki-67 antigen (MIB-1 antibody) was performed in paraffin-embedded tissue sections obtained from 25 resected human gliomas. Additionally, cultured human glioma cells were subjected to simultaneous flow cytometry to determine Topo IIalpha and DNA content. Using flow cytometric analysis, the authors found that the Topo IIalpha antibody labeled cells in the S, G2, and M phases of the cell cycle and also those in some parts of the G0 and G1 phases. In histological sections, Topo IIalpha showed more distinct staining than MIB-1, particularly in older archival cases. The proliferative indices (PIs) based on cells staining for MIB-1 and Topo IIalpha correlated highly with one another (r = 0.96). The Topo IIalpha PI immunopositivity was seen in 4.07% of cells in the low-grade astrocytoma group, 11.97% in the anaplastic astrocytoma group, and 13.84% in the glioblastoma multiforme group, representing significant differences between low-grade astrocytoma and both anaplastic astrocytoma and glioblastoma. A Topo IIalpha PI less than 5% predicted longer patient survival (p = 0.003).

CONCLUSIONS

Immunostaining for Topo IIalpha represents a useful alternative to MIB-1 as a proliferative index in human gliomas.

Ki-67 (clone MIB-1) proliferation index in recurrent glial neoplasms: no prognostic significance

BACKGROUND

To determine if the Ki-67 (MIB-1 clone) proliferative index (PI) has prognostic potential in patients with recurrent astroglial neoplasms.

METHODS

We conducted a retrospective review of 27 patients whose initial and recurrent specimens were available. Histopathology was determined according to the World Health Organization classification. Proliferation index was calculated on formalin-fixed tissue using the Ki-67 (MIB-1 clone) antibody. Morphometric data were analyzed in conjunction with clinical data and Cox Proportionate Hazards Analysis, Spearman's correlation coefficient and Mann-Whitney Test.

RESULTS

Initial histopathology included 14 glioblastoma multiforme, 7 anaplastic astrocytoma, 3 oligoastrocytoma, and 3 astrocytoma. Recurrent specimens showed changes consistent with treatment. While univariate analysis shows initial histology correlated with survival (p<0.036), PI did not correlate with survival after either initial (p = 0.86) or recurrent (p = 0.46) surgery for any tumor type. PI difference between specimens also did not correlate with survival (p = 0.91). Initial PI did not correlate with recurrent PI either (p = 0.43).

CONCLUSIONS

Ki-67 PI does not confer additional prognostic information for patients with recurrent astroglial neoplasms. One possible explanation for this observation is that treatment may alter the PI independent of its effect on tumor growth.

Proliferating cell nuclear antigen (PCNA) in cerebral cavernomas: an immunocytochemical study of 42 cases

BACKGROUND

The natural history and growth mechanisms of cerebral cavernous angiomas are unclear, which makes them difficult to manage. We attempted to evaluate the evolutive potential of cavernomas by studying the proliferative capacity of cells.

METHODS

We studied 42 histologically verified cavernomas with monoclonal antibody to proliferating cell nuclear antigen (PCNA), an accessory protein of the cell cycle, the rate of which is increased in proliferative cells. The PCNA Labeling Index (PCNA LI) was calculated in each case, and the results were compared with histologic findings (lacy areas, thick walls, thrombi, hemosiderin) and clinical features (epilepsy, hematomas, pseudotumorous signs).

RESULTS

Thirty-six of 42 cases (85.7%) revealed stained cells. PCNA LI ranged from 1 to 48% (mean: 23.39%). Statistical analyses showed a positive correlation between PCNA LI and the extent of lacy areas (p < 0.05). On the contrary, collagenous-walled and thrombotic areas rarely showed positively stained cells. We found no relationship between PCNA LI and clinical features.

CONCLUSIONS

A proliferative capacity of endothelial cells does exist in some areas of cavernomas and may explain, besides thromboses and hemhorrages, the growth and even de novo appearance of these lesions. Occurrence of fragile blood cavities, thickening of others, and changes in blood flow may influence the evolution of lesions. Our results suggest that in cavernomas, some areas may undergo specific changes, which makes them more dynamic lesions than previously thought.

Nearest-neighbor classification for identification of aggressive versus nonaggressive low-grade astrocytic tumors by means of image cytometry-generated variables

The authors investigated whether cytometry-related variables generated by means of computer-assisted microscopic analysis of Feulgen-stained nuclei can contribute significant information toward the characterization of low-grade astrocytic tumor aggressiveness. This investigation was conducted using the nearest-neighbor rule (a traditional classification method used in pattern recognition) to analyze a series of 250 supratentorial astrocytic tumors from adult patients. This series included 39 low-grade astrocytomas and 211 high-grade astrocytic tumors (including 47 anaplastic astrocytomas and 164 glioblastomas multiforme [GBMs]). The results show that the 3-nearest-neighbors rule enabled a subgroup of "atypical" astrocytomas to be distinguished from the "typical" tumors. The atypical astrocytoma species exhibited a DNA content (DNA ploidy level) and morphonuclear characteristics that were statistically more similar to the characteristics of GBMs than to those exhibited by the typical astrocytomas. An analysis of survival data revealed that patients with atypical astrocytomas survived for a significantly shorter period (p < 0.001) than patients with typical lesions of this kind. In fact, patients with atypical astrocytomas had a survival period similar to that of patients with anaplastic astrocytomas, whereas patients with typical astrocytomas had a survival period significantly longer (p < 0.0001) than those associated with anaplastic astrocytomas and GBMs.

Functional characterization of brain tumors: an overview of the potential clinical value

Early detection and characterization are still challenging issues in the diagnostic approach to brain tumors. Among functional imaging techniques, a clinical role for positron emission tomography studies with [18F]-fluorodeoxyglucose and for single photon emission computed tomography studies with [201Tl]-thallium-chloride has emerged. The clinical role of magnetic resonance spectroscopy is still being defined, whereas functional magnetic resonance imaging seems able to provide useful data for presurgical localization of critical cortical areas. Integration of morphostructural information provided by computed tomography and magnetic resonance imaging, with functional characterization and cyto-histologic evaluation of biologic markers, may assist in answering the open diagnostic questions concerning brain tumors.

Bromodeoxyuridine labeling index in glioblastoma multiforme: relation to radiation response, age, and survival

PURPOSE

Various measures of the rate of tumor cell proliferation have been found to predict survival in patients with intracerebral gliomas. We correlated the bromodeoxyuridine labeling index (BrdUrd LI) with the response to radiation therapy, survival, and known prognostic factors in a series of patients with glioblastoma multiforme (GM) to test its utility as a prognostic factor.

METHODS AND MATERIALS

The BrdUrd LI was determined in 200 newly diagnosed intracranial GMs. Age and sex were known for all patients. The response to radiation therapy was determined in 116 patients by comparing neuroimaging studies obtained before and after external beam radiation therapy. Survival was analyzed in 64 patients who were treated according to two consecutive prospective clinical protocols.

RESULTS

The median BrdUrd LI was 6.5% (mean, 7.2%; range, 1.1-25.4%). The BrdUrd LI did not correlate significantly with age, sex, radiation response, or survival. Age and Karnofsky performance score were independent prognostic factors in our cohort.

CONCLUSION

The proliferative rate as measured by BrdUrd LI was not a prognostic factor in our GM cohort. The BrdUrd LI did not correlate significantly with known prognostic factors in GM. There was no significant relationship between BrdUrd LI and radiation response.

Longer survival in high grade gliomas: intraoperative radiation therapy (IORT) and immunocytochemical assessment of their growth potential

The authors report prolonged survival in patients with high grade (grade 3 and 4) gliomas who were given additional intraoperative radiation therapy (IORT) and discuss survival in relation to the immunocytochemical assessment of their tumours. Of 54 selected patients with high grade gliomas treated with multimodal therapy including IORT during the years from 1985 to 1989, 11 had long-term survival over 5 years after the initial treatment. The clinicopathological features, analysed retrospectively, that were associated with prolonged survival were: (1) epileptic seizures, (2) initial CT scans showing a small mass without contrast enhancement which developed into an enhancing larger mass on follow up, (3) tumour location which was frequently frontal and near the cortical surface, (4) 20-30 Gy irradiation (mean 25.5 Gy) in IORT delivered in one fraction to the post-resection tumour bed, and (5) a low proliferating cell nuclear antigen (PCNA) labelling index (LI). The most favourable prognostic indicator was found to be a low PCNA LI.