Prognostic indicators in a range of astrocytic tumours: an immunohistochemical study with Ki-67 and p53 antibodies

Mindbomb Homolog-1 Index in the Prognosis of High-Grade Glioma and Its Clinicopathological Correlation

Introduction:

Gliomas are the most common brain tumors in adults originating from the glial cells. Glioblastoma multiforme is the most malignant and frequent among all gliomas. In recent years, the antibody Mindbomb Homolog-1 (MIB-1) has evolved as a measure of the proliferative nature of the glial tumors. This study aims to investigate the MIB-1 index value as an independent prognostic factor in high-grade gliomas and its correlation with outcome and survival.

Materials and Methods:

Mean MIB-1 index was determined in 51 high-grade glioma tissue samples in formalin. Its correlation with outcome by assessing the clinicoradiological parameters and median survival of patients in months were assessed. Survival analysis was studied by using the Kaplan–Meier bivariate analysis and Cox proportional ratio.

Results:

Preoperative Karnofsky Performance Score, WHO-PS, Neurological Performance Scale, and Mini–Mental Status Examination (MMSE) were statistically significant with respect to outcome and survival, whereas tumor factors such as size and perilesional edema were not. In particular, midline-crossing tumors and deep-seated tumors were significantly associated with high MIB-1 index and by correlation with outcome. There were significantly higher number (P < 0.0001) of patients with Grade IV tumors, with an MIB-1 index value above an arbitrary cutoff of 10% compared to Grade III tumors. In addition, median survival period of patients with low MIB-1 index was longer irrespective of tumor grade.

Conclusion:

Significant correlation between high-grade glioma and MIB-1 index suggests MIB-1 index to be a good prognostic tool, with MIB-1 index and midline-crossing variables being independent prognostic parameters.

Prognostic Significance of Histologic and Cytometric Factors in Supratentorial Astrocytomas

There is no agreement in the literature on selecting the principal parameters that contribute to explain the different outcomes in supratentorial astrocytomas. Hence, we designed a global study using morphologic parameters and DNA quantification measured by flow cytometry (FCM) and image analysis (IA) on 116 tumors contrasting the results with patients' survival in a univariate and multivariate study. In the Kaplan-Meier study besides the necrosis (p<0.0001) there were other parameters with significant prognostic value such as nuclear atypia (p=0.0001), presence of anaplastic large cells (p=0.0003) and the morphology of the tumor vessels (p=0.009). Proliferative parameters like mitotic index, cell density, the cell fraction in S phase or G2/M phase, and the proliferative phase measured by image analysis (IA) or ploidy patterns did not influence the prognosis. In the Cox's proportional hazards model the presence of necrosis remained as the only prognostic predictor (p=0.001) and increased 5.9 times the risk of mortality in gliomas.

Ki-67 is a valuable prognostic factor in gliomas: evidence from a systematic review and meta-analysis

Ki-67 has been widely used as an indicator of cell proliferation in gliomas. However, the role of Ki-67 as a prognostic marker is still undefined. Thus, we conducted a meta-analysis of the published literatures in order to clarify the impact of Ki-67 on survival in glioma cases. Eligible studies were identified in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, Science Direct and Wiley Online Library with the last search updated on August 31, 2014. The clinical characteristics, overall survival (OS) and progression- free survival (PFS) together with Ki-67 expression at different time points were extracted. A total of 51 studies, covering 4,307 patients, were included in the current meta-analysis. The results showed that overexpression of Ki-67 can predict poor OS (HR=1.66, 95%CI: 1.53-1.80; Z=11.87; p=0.000) and poor PFS (HR=1.67, 95%CI: 1.47-1.91; Z=7.67; p=0.000) in gliomas. Moreover, subgroup analyses also indicated that high level of Ki-67 expression was related to poor OS and PFS in glioma patients regardless of region, pathology type, cut-off value and statistical method. In conclusion, the current meta-analysis revealed that Ki-67 expression might be a predicative factor for poor prognosis of glioma patients, emphasizing its importance as a predictor.

Insights into the prognostic value of DJ-1 and MIB-1 in astrocytic tumors

BACKGROUND

The histological grade is the gold standard for the evaluation of prognosis of astrocytic tumors. Nevertheless, morphologic criteria are not always accurate prognostic indicators.

AIM

The research investigates the expression of MIB-1 and DJ-1 in different grades of astrocytomas and evaluates the possible prognostic role of DJ-1 in these tumors in relation to other prognostic parameters including the MIB-1 labeling index.

MATERIALS AND METHODS

Immunohistochemical expression of MIB-1 and DJ-1 was evaluated in 111 samples of astrocytic tumors comprising 28 diffuse astrocytomas, 38 anaplastic astrocytomas and 45 glioblastomas. The univariate survival analysis was done using the Kaplan-Meier method and the multivariate survival analysis was done using Cox proportional hazard model.

RESULTS

The statistical analysis revealed a significant correlation between each of DJ-1 and MIB-1 and the histological grade of astrocytomas. The univariate analysis showed that high grade, high DJ-1 score and MIB-1 labeling index ≥ 10.1 were associated with poor survival. Multivariate analysis for all the studied astrocytomas proved the independent prognostic significance of the histological grade and DJ-1 score. Meanwhile, the multivariate analysis for each grade emphasized that DJ-1 was the only independent prognostic indicator in high-grade astrocytomas.

CONCLUSION

This study emphasized the effectiveness of high DJ-1 expression in predicting poor survival of astrocytoma patients, when compared to MIB-1. DJ-1 could be particularly important in cases with discrepancies between the morphologic criteria and clinical parameters.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1070116023943146.

Predictors of long-term survival in patients with glioblastoma multiforme: advancements from the last quarter century

Over the last quarter century there has been significant progress toward identifying certain characteristics and patterns in GBM patients to predict survival times and outcomes. We sought to identify clinical predictors of survival in GBM patients from the past 24 years. We examined patient survival related to tumor locations, surgical treatment, postoperative course, radiotherapy, chemotherapy, patient age, GBM recurrence, imaging characteristics, serum, and molecular markers. We present predictors that may increase, decrease, or play no significant role in determining a GBM patient's long-term survival or affect the quality of life.

Image-guided resection of high-grade glioma: patient selection factors and outcome

OBJECT

In patients with glioma, image-guided surgery helps to define the radiographic limits of the tumor to maximize safety and the extent of resection while minimizing damage to eloquent brain tissue. The authors hypothesize that image-guided resection (IGR) techniques are associated with improved outcomes in patients with malignant glioma.

METHODS

Data recorded in 486 patients enrolled in the Glioma Outcomes Project were analyzed in this study. Demographic data and outcomes in patients who underwent IGR were compared with those in patients who underwent resection without IGR. Univariate analysis performed with chi-square testing was used to compare patient presentation, tumor characteristics, and death rates. Multivariate logistic regression was used to predict various outcome parameters. Patients who underwent IGR were younger and had smaller, lower-grade tumors than those in whom IGR was not performed. They were more likely to present with seizure and normal consciousness. Unexpectedly, gross-total resection was performed in significantly fewer patients with IGR than in individuals without IGR. Patients with IGR were more likely to be discharged home with the ability to live independently, and they had a shorter duration of hospital stay than patients without IGR. Survival was significantly longer in patients who underwent IGR, but multivariate analysis showed that glioblastoma multiforme (GBM) and age accounted for these observations.

CONCLUSIONS

Selection bias occurs regarding patients who receive IGR; these biases include younger age, presentation with seizure and normal level of consciousness, tumor diameter less than 4 cm, and non-GBM on histopathological studies. Outcome appears to be improved in patients who undergo IGRs of high-grade gliomas. It is unclear if these improved outcomes are due to the selection of a more favorable patient population or to the IGR techniques themselves. It is likely that the full potential of image guidance in glioma surgery will not be realized until it is applied to a wider range of patients.

Surgery for malignant gliomas: mechanistic reasoning and slippery statistics

Current surgical treatment of malignant gliomas largely depends on mechanistic reasoning and data collected in non-randomised studies. Technological advance has enabled more accurate resection of tumours and preservation of eloquent brain areas but ethical considerations have restricted randomised trials on the efficacy of surgery to one small trial that found a 3 month survival advantage for patients over age 65 years who received surgery and interim analysis of a larger trial. There is an argument for surgery as a palliative measure in patients with symptoms caused by mechanisms that are surgically remediable. Whether there is any survival advantage from surgery in patients other than those with immediately life-threatening, surgically remediable complications, such as raised intracranial pressure, is unclear. The available data show that if such an advantage does exist, it is modest at best. Adjuvant treatments given surgically are being studied. Chemotherapy wafers are the most prominent of the adjuvant treatments but the evidence available is insufficient to recommend their use in routine practice. In this review we examine the prevailing mechanistic model and observational data; we assess how these are applied and the priorities they indicate for future research.

Subependymal giant cell astrocytoma: a clinicopathological study of 23 cases with special emphasis on proliferative markers and expression of p53 and retinoblastoma gene proteins

AIMS

To gain a better insight into the biological behaviour of subependymal giant cell astrocytoma (SEGA), tumour suppressor gene protein expression and various proliferative indices were studied in these tumours and correlated with histological features and clinical outcome.

METHODS

We studied 23 cases of SEGA, 19 from our own Institute and four from the National Institute of Mental Health and Neurological Sciences (NIMHANS), Bangalore, India. Immunohistochemical staining for various glial and neuronal markers, proliferative markers (MIB-1, Topoisomerase II alpha PCNA) and tumour suppressor gene protein expression of p53 and retinoblastoma (Rb) were performed.

RESULTS

Nineteen cases of SEGA were collected over a period of 23 years (January 1978-December 2001), which accounted for 0.16% of all intracranial tumours and 0.51% of all gliomas reported at this centre. Ages ranged from 4 to 37 years (mean 13.2 years) with a male preponderance. Nine of the 23 cases were associated with tuberous sclerosis (TS), six at the time of diagnosis, while three developed TS during the follow-up period. Treatment consisted of surgical resection (total in nine cases and subtotal in 14 cases) followed by radiotherapy in seven cases. Except for two patients who died in the immediate post-operative period of surgical complications, the remaining patients were all alive in the follow-up period (mean 37.1 months). One patient experienced recurrence 22 years after the first surgery and a second patient after 2 years. Necrosis and/or mitoses were observed in five cases. Immunohistochemically, tumours were positive for both glial and neuronal markers. Interspersed inflammatory cells were a mixture of mast cells and lymphocytes of T immunophenotype. The MIB-1 labelling index (LI) ranged from 0 to 8% (mean 3.0%), topoisomerase II alpha (topo II alpha) LI from 0 to 9.5% (mean 2.9%) and PCNA LI from 10 to 59% (mean 32.5%). The difference in the labelling indices of tumours with and without mitoses and/or necrosis was not statistically significant. None of the tumours revealed loss of Rb gene protein expression. p53 immunopositivity was seen in 14 cases (labelling indices ranged from 1 to 7.3% with a mean of 2.4%). The correlation between the MIB-1 LI and topo II alpha LI, and topo II alpha LI and PCNA LI was significant (P<0.05) but not so with other parameters like p53 protein expression, duration of survival and morphological features such as mitoses and necrosis.

CONCLUSIONS

SEGAs are rare intraventricular tumours associated with TS and express both neuronal and glial markers. They have a low proliferative potential. Mitoses and necrosis are not associated with a worse prognosis. In view of the low proliferative indices and long survival of these patients without recurrence, the role of post-operative radiotherapy is questionable. These patients should be followed up closely as many of them develop stigmata of tuberous sclerosis at a later stage.

Loss of heterozygosity of a locus in the chromosomal region 17p13.3 is associated with increased cell proliferation in astrocytic tumors

We had previously reported that loss of heterozygosity (LOH) of the D17S379 locus on 17p13.3 was significantly more frequent in high-grade gliomas (anaplastic astrocytoma, AA; glioblastoma multiforme, GBM) than in those of a low-grade diffuse astrocytoma (DA); however, this was independent of alterations at the TP53 locus, We also showed that LOH of D17S379 was associated with positive staining for p53 protein on immunohistochemistry, but LOH of the TP53 gene had no such association. In this work we show that cell proliferation as determined by MIB-1 labeling index (LI) was significantly higher in tumors with LOH of D17S379 than those with no LOH (NLOH). In accord with our previous results, p53 protein immunopositivity was also associated with increased MIB-1 LI; however, we observed no such association of LI with TP53 LOH. The results further confirm that alteration of one or more putative tumor suppressor loci at 17p13.3 is associated with increased proliferation in astrocytic tumors.

Morphophenotypic variation predicts clinical behavior in childhood non-desmoplastic medulloblastomas

Histopathologic assessment of 273 non-desmoplastic medulloblastomas (MBs) from children aged 3 to 16 years and entered into the SIOP/UKCCSG (International Society of Pediatric Oncology/United Kingdom Children's Cancer Study Group) PNET3 trial revealed that 47 (17%) fulfilled criteria for the recently proposed anaplastic variant. In addition, an anaplastic phenotype was focally present in all 5 (2%) large cell MBs from this series. Children with large cell MBs had the worst outcome, but there was also a significant difference between the event-free and overall survivals of children with classic MBs and those with anaplastic MBs. While objective morphometric analysis confirmed that subjective evaluation of nuclear size and variability contributed to the separation of MBs into classic, anaplastic, and large cell variants, these cytologic measures were not themselves prognostic indicators. However, anaplastic and classic MBs also possessed significantly different mitotic counts/indices, and these measures of proliferation were related to survival. Significant prognostic indicators in a multivariate survival analysis were histologic variant, metastases at presentation, and subtotal surgical excision of tumor. Our study supports the concept of an anaplastic variant among MBs, demonstrating that it has clinical utility.

Clinical and pathologic relevance of p53 index in canine osseous tumors

The clinicopathologic value of the immunohistochemical (IHC) expression of p53 protein was evaluated in 167 canine osseous tumors. p53 staining frequency and intensity in tumor cells was expressed as a p53 index. p53 index was significantly higher in osteosarcomas than in other sarcomas, chondrosarcoma, multilobular tumor of bone, and tumors initially misdiagnosed as osteosarcomas as well as in appendicular versus axial and in distal versus proximal osteosarcomas. A strong correlation is demonstrated between the p53 index and a range of clinicopathologic parameters in osteosarcoma, including the tumor site, histologic grade and score, mitotic index, degree of tumor necrosis, and pleomorphism. Chondroblastic osteosarcomas had significantly higher and telangiectatic osteosarcomas significantly lower p53 index than did osteosarcomas belonging to other histopathologic subtypes, a fact that tends to reinforce the perception of these osteosarcomas as distinct clinicopathologic entities. Entire males had higher p53 index than did neutered males. p53 index was higher in Rottweilers than in Great Danes and Terriers, confirming breed susceptibilities to osteosarcoma. p53 index showed no association with age, primary or secondary site status, or the presence of metastases or other tumor types. Biopsy samples had a higher p53 index than did postmortem samples, either because of differences in sample processing or the possibility that p53 overexpression is more evident at the earlier stages of osteosarcoma pathogenesis, presumably represented by the biopsy material. IHC examination for p53 and the derived index has the potential to be used as an additional diagnostic tool and prognostic indicator for osseous tumors.

Prediction of clinical course of diffusely infiltrating astrocytomas from telomerase expression and quantitated activity level

Telomerase, one of the reverse transcriptases that extend telomere length, has been suggested to facilitate tumorigenesis and tumor immortality. Little is yet known, however, concerning the clinical significance of telomerase expression in brain tumors. We found in the present study that telomerase expression may contribute to malignant progression and can be an important indicator of high grade diffusely infiltrating astrocytomas, and its quantitated activity level reflects their growth potential. Telomerase expression and its quantitated activity level are also a good predictor of clinical course as compared with other biological markers and clinical factors.

Ki-67 immunoreactivity, basic fibroblastic growth factor (bFGF) expression, and microvessel density as supplementary prognostic tools in low-grade astrocytomas. An immunohistochemical study with special reference to the reliability of different Ki-67 antibodies

Low-grade diffuse astrocytomas are generally slow-growing tumors; however, they may progress to anaplastic astrocytomas or glioblastomas. As existing grading systems fail to distinguish these tumors, ongoing research strives to identify new prognostic markers. In this study, 22 adult patients with supratentorial diffuse astrocytomas, WHO grade II, were investigated to clarify whether proliferative activity, assessed by different Ki67 antibodies (MIB-1, NC-MM1, NC-Ki67p, rahKi67), expression of basic fibroblast growth factor (bFGF) or microvessel density have prognostic power. The Ki67 antibodies revealed low proliferation indices (PI); however, there was a wide spread of values, ranging from 0.1% to about 10%. In general, a positive correlation between the different Ki67 PIs was found. In 12 of 22 cases, bFGF immunoreactivity was recorded. Microvessel density was generally low. MIB-1 PI was the only prognostic factor of statistical significance. Ki67 PI, obtained by using the monoclonal antibody MIB-1, can thus serve as a prognostic factor capable of identifying subsets of low-grade diffuse astrocytomas with a potentially more aggressive clinical behavior.

Classifying the medulloblastoma: insights from morphology and molecular genetics

Significant advances in the treatment of the medulloblastoma (MB) have been made in the last 30 years, reducing mortality by 2-fold. Further improvements in the cure rate require an increased understanding of the biology of MBs, and this will translate into refinements in their classification. Scrutiny of the cytological variation found among MBs has recently led to the concept of the anaplastic MB, which overlaps the large-cell variant and appears to share its poor prognosis. In contrast, the MB with extensive nodularity, a distinctive nodular/desmoplastic variant occurring in infants, has a better outcome than most MBs in these young patients. Building on cytogenetic studies that have drawn attention to abnormalities on chromosome 17 in over a third of MBs, research shows non-random losses on chromosomes 8, 9, 10, 11 and 16, and gains on chromosomes 1, 7 and 9. Overexpression of ErbB2 receptors and losses on chromosome 17p have been proposed as independent indicators of aggressive behaviour, while high TrkC receptor expression indicates a favourable outcome. There is a strong association between anaplastic/large-cell tumours and MYC amplification, which has previously been linked with aggressive disease, but associations between abnormalities on chromosome 17 and anaplastic/large-cell MBs and between abnormalities in the shh/PTCH pathway and the desmoplastic variant are more controversial. Classification of the MB histopathologically and according to profiles of molecular abnormalities will help both to rationalize approaches to therapy, increasing the cure rate and reducing long-term side-effects, and to suggest novel treatments.

Immunohistochemical markers for prognosis of cerebral glioblastomas

Glioblastoma is the commonest neuroectodermal tumor and the most malignant in the range of cerebral astrocytic gliomas. The prognostic utility of various biological markers for glioblastomas has been broadly tested but the results obtained are regarded as controversial. In the present study, 302 glioblastoma specimens were studied to evaluate a possible association between clinical outcome and expression of some immunohistochemical variables. Furthermore, tumors examined were subdivided on the three cytological subsets--small-cell (SGB), pleomorphic-cell (PGB) and gemistocytic (GGB). Immunohistochemical variables differed between various subsets: the number of p53-positive tumors was found to be prevailed among the PGB, whereas the number of tumors with EGFR and mdm2 positivity was significantly greater in SGB. GGB contained significantly lowest mean proliferating cell nuclear antigen (PCNA) labeling index (LI), greater number of p21ras positive cases, and higher mean apoptotic index (AI). Survival time in patients with SGB, EGFR and mdm2-positivity and PCNA LI >40% was found to be significantly shorter, whereas presence of p21ras and AI >0.5% were associated with prolonged survival. Multivariate analysis revealed that survival time is associated with SGB, EGFR-positivity, and AI (p = 0.0023, p = 0.0035 and p = 0.0029 respectively). We conclude that although some immunohistochemical variables were found to be significant for glioblastoma outcome, they appear to be closely related to biology of single cytological subsets. Furthermore, these variables exhibited no prognostic value when they were analyzed within each cytological subset separately. Therefore, the glioblastoma subdivision on three cytological subsets proposed by us is carrying some element of rationality but, undoubtedly, requires further prospective studies.

High expression of DNA topoisomerase IIalpha and Ki-67 antigen is associated with prolonged survival in glioblastoma patients

Assessment of tumour cell proliferation in glioblastoma (GB) has been a topic of considerable research interest over the past decade. However, the correlation of tumour proliferation and patient outcome has yielded controversial results. In this study, we examined immunohistochemically, using paraffin-embedded tissue, the expression of the proliferation-related markers DNA topoisomerase IIalpha (TIIalpha) and Ki-67 antigen in a cohort of 114 GB patients treated consecutively with surgery and radiochemotherapy, and correlated the expression with patient outcome. The TIIalpha labelling index (LI) ranged between 5.2 and 87.2% (median: 25.6%). Survival analysis disclosed an association between high TIIalpha expression levels and prolonged survival (P=0.040, log-rank test). TIIalpha expression correlates closely with Ki-67 labelling index (R=0.927, P<0.001), which itself is predictive of patient survival (P=0.044). However, in multivariate analysis, only the Karnofsky performance status remained predictive of patient survival. We conclude that high expression of TIIalpha and Ki-67 appears to be associated with a prolonged survival in our cohort of GB patients.

Immunohistochemical markers for prognosis of anaplastic astrocytomas

Among the entire spectrum of astrocytic neoplasms, just anaplastic astrocytoma (or grade III astrocytoma) appears to be a more enigmatic tumor entity with vague criteria for pathological diagnosis, unclear biological behavior and diverse clinical outcome. Attempts have been made to identify biological markers that would be useful in prediction of prognosis of anaplastic astrocytomas but the results obtained are controversial. In the present study, survival data on 63 patients with anaplastic astrocytoma were studied to evaluate a possible association between clinical outcome and expression of some immunohistochemical variables. Both the progression-free (PFS) and overall (OS) survival times were significantly reduced for patients older than 45 years, for anaplastic astrocytomas containing multiple mitoses, for Ki-67 LI > 5%, for cyclin A LI > 4% and for PTEN-negative tumors. We found no differences in survival times in patients with or without p53 immunoreactivity and also in cases with different values of p16 and p27 immunostaining. Multivariate analysis revealed that risk of tumor progression and death is independently associated with tumors containing multiple mitoses and for PTEN-negative tumors. According to the data from the CART modeling, tumors were subdivided based on the three following subsets: (1) Anaplastic astrocytomas with solitary mitosis. (2) Anaplastic astrocytomas with multiple mitoses and PTEN positivity. (3) Anaplastic astrocytomas with multiple mitoses and PTEN negativity. Thus, the results obtained reveal the advantage of combined approach including evaluation of routine histological parameters and immunohistochemical variables for further clinical subdivision of anaplastic astrocytomas.

Evaluation of molecular markers in low-grade diffuse astrocytomas: loss of p16 and retinoblastoma protein expression is associated with short survival

Diffuse astrocytomas have a median survival of 6-8 years. However, in a minority of cases that are histologically low grade, progression is rapid, leading to death within 2 years. Loss of p16, retinoblastoma protein, and deleted-in-colon-carcinoma protein expression, and monosomy of chromosome 10 have been shown to occur in malignant astrocytic tumors. We have investigated the prognostic value of expression of these markers, using techniques applicable in many histopathology laboratories, in diffuse astrocytomas that are histologically low grade. Paraffin sections from 71 diffuse, supratentorial, low-grade astrocytomas, from patients with at least 8-year survival data, were immunostained with antibodies to p16, deleted-in-colon-carcinoma protein, p53, Ki67, and retinoblastoma protein. In situ hybridization with a digoxigenin-labeled probe to chromosome 10 was used to assess chromosomal loss. In most cases there was immunostaining of virtually all tumor cell nuclei with antibodies to p16 and retinoblastoma protein. Three of the 68 tumors in which assessment of p16 was possible included discrete foci with lack of detectable immunoreactivity in tumor cells. The three patients concerned had a significantly shortened median survival (1.1 years vs 4.4 years in those without loss of p16; p <0.01). In six of the 61 cases where assessment of retinoblastoma protein was possible, <70% of tumor cell nuclei showed immunoreactivity. These six patients had a shorter survival (4.0 years) than had the remaining patients (5.4 years), although this difference was not statistically significant. The tumor from one of these patients included areas where only 36% of tumor cells showed retinoblastoma protein immunoreactivity, and this patient survived only 1.5 years. Tumors showing loss of both p16 and retinoblastoma were not seen. p53 and deleted-in-colon-carcinoma protein expression was highly variable and did not correlate with survival. Tumors with monosomy for chromosome 10 were not identified. Both polyploidy and the Ki67 labeling index were significantly associated with the p53 labeling index but not with survival. Focal loss of p16 or retinoblastoma protein is demonstrable in approximately 5% and 10% of diffuse low-grade diffuse astrocytomas, respectively. Tumors with focal loss of immunoreactivity for these proteins are associated with shorter survival than those without, suggesting that immunohistochemistry for p16 and retinoblastoma protein may be a useful adjunct to other methods for assessing the prognosis of astrocytomas.

The significance of immunohistochemistry in the diagnosis and therapy of neoplasms

This review article details the diagnostical significance of immunohistochemistry, which has developed during the last quarter of the century. Certainly, the advancement of monoclonal antibody technology has been of great significance in assuring the place of immunohistochemistry in the modern accurate microscopic diagnosis of human neoplasms, as a method of choice in histopathology. The fact still remains that in order to properly assess any immunohistochemical reactivity used for differential diagnostic purposes, the target cells have to be identified as neoplastically transformed cells by routine histopathological techniques. Selected groups of target molecules of great significance in cancer biology are discussed. The discovery of neoplasm-associated antigens has not only made the more accurate diagnosis of human cancer feasible but has also shed light on the extensive immunophenotypical heterogeneity of even the most closely linked human malignancies. The identification of disseminated neoplastically transformed cells by immunohistochemistry has allowed for a clearer picture of cancer invasion and metastasis, as well as the evolution of the tumour cell associated immunophenotype towards increased malignancy. Some possibilities of neoplasm-associated antigen targeted, receptor-directed immunotherapy are discussed and reviewed in this manuscript. Future antineoplastic therapeutical approaches should see the inclusion of a variety of immunotherapies, in the form of an individualised 'cocktail' specific for the particular immunophenotypical pattern associated with each individual patient's neoplastic disease.

Ki-67 labeling is correlated with the time to recurrence in primary glioblastomas

The Ki-67 labeling index (LI) was shown in many cut-off studies to be significantly correlated to the postoperative survival probability in gliomas in univariate and multivariate analyses. However, a direct relationship of the Ki-67 LI and the growth fraction, respectively, to clinical growth parameters was not demonstrated in a single tumor type of this group until now. We compared the Ki-67 LI of 20 primary glioblastomas and their recurrent tumors with the time to reoperation for recurrence. Regression analyses showed (1) a high reproducibility of the LIs at the second versus the first operation corresponding to an inherent growth potential of a given individual tumor and (2) a strong inverse correlation of LI to time to recurrence (TR) (r = -0.92). Additionally to a lower LI (corresponding to a smaller growth fraction), a longer cycle time could be derived in slowly growing as compared to rapidly growing tumors. A direct relationship of the Ki-67 LI to a clinical time parameter (the TR) was obtained, and a predictive significance of individual LIs in glioblastomas could be defined.

Ki67 protein: the immaculate deception?

This article updates our previous review of Ki67 published in Histopathology 10 years ago. In this period the numbers of papers published featuring this antibody has increased 10-fold from 338 to 3489 indicating the considerable enthusiasm with which this antibody has been studied. This review attempts to provide an update on the characterization of the Ki67 protein, its function and its use as a prognostic or diagnostic tool.

Invasiveness in vitro and biological markers in human primary glioblastomas

Invasion of spheroids from 20 human primary glioblastomas into precultured fetal rat brain tissue in culture has been studied and quantified. Between 30 and 98 percent of the normal brain tissue was destroyed by invading glioma cells within 4 days. The degree of invasion did not correlate with patient survival. A slightly higher invasiveness and shorter survival was seen in tumors with EGF receptor overexpression, and the opposite pattern was found for tumors with a TP53 mutation. The degree of invasiveness in vitro was far higher than would be expected from the dynamics of clinically observed tumor spread. This suggests that mechanisms suppressing invasion may be operative in the normal brain; alternatively the differences may be due to a higher permissiveness of the fetal brain tissue for invasion in vitro.

Aberrant localization of the neuronal class III beta-tubulin in astrocytomas

BACKGROUND

The class III beta-tubulin isotype (betaIII) is widely regarded as a neuronal marker in development and neoplasia. In previous work, we have shown that the expression of betaIII in neuronal/neuroblastic tumors is differentiation dependent. In contrast, the aberrant localization of this isotype in certain nonneuronal neoplasms, such as epithelial neuroendocrine lung tumors, is associated with anaplastic potential.

OBJECTIVE

To test the generality of this observation, we investigated the immunoreactivity profile of betaIII in astrocytomas.

DESIGN

Sixty archival, surgically excised astrocytomas (8 pilocytic astrocytomas, WHO grade 1; 18 diffuse fibrillary astrocytomas, WHO grade 2; 4 anaplastic astrocytomas, WHO grade 3; and 30 glioblastomas, WHO grade 4), were studied by immunohistochemistry using anti-betaIII monoclonal (TuJ1) and polyclonal antibodies. A monoclonal antibody to Ki-67 nuclear antigen (NC-MM1) was used as a marker for cell proliferation. Antibodies to glial fibrillary acidic protein (GFAP) and BM89 synaptic vesicle antigen/synaptophysin were used as glial and neuronal markers, respectively.

RESULTS

The betaIII immunoreactivity was significantly greater in high-grade astrocytomas (anaplastic astrocytomas and glioblastomas; median labeling index [MLI], 35%; interquartile range [IQR], 20%-47%) as compared with diffuse fibrillary astrocytomas (MLI, 4%; IQR, 0.2%-21%) (P <.0001) and was rarely detectable in pilocytic astrocytomas (MLI, 0%; IQR, 0%-0.5%) (P <.0001 vs high-grade astrocytomas; P <.01 vs diffuse fibrillary astrocytomas). A highly significant, grade-dependent relationship was observed between betaIII and Ki-67 labeling and malignancy, but this association was stronger for Ki-67 than for betaIII (betaIII, P <.006; Ki-67, P <.0001). There was co-localization of betaIII and GFAP in neoplastic astrocytes, but no BM89 synaptic vesicle antigen/synaptophysin staining was detected.

CONCLUSIONS

In the context of astrocytic gliomas, betaIII immunoreactivity is associated with an ascending gradient of malignancy and thus may be a useful ancillary diagnostic marker. However, the significance of betaIII-positive phenotypes in diffuse fibrillary astrocytomas with respect to prognostic and predictive value requires further evaluation. Under certain neoplastic conditions, betaIII expression is not neuron specific, calling for a cautious interpretation of betaIII-positive phenotypes in brain tumors.

Prognostic value of the expression of tumor suppressor genes p53, p21, p16 and prb, and Ki-67 labelling in high grade astrocytomas treated with radiotherapy

Cumulative inactivation of tumor suppressor genes and/or amplification of oncogenes lead to progressively more malignant astrocytic tumors. We have analyzed the significance of tumor suppressor genes p53, p21, p16 and retinoblastoma protein (pRb) and proliferative activity for survival in 77 high grade astrocytic tumors. After operation, the patients--25 anaplastic astrocytomas (AA) and 52 glioblastomas (GBs)--were treated with similar radiotherapy. The expression of the suppressor genes and the proliferative activity were analyzed immunohistochemically. p53 immunopositivity was found in 44% of AAs and 46% of GBs. Tumors with aberrant p53 expression had lower proliferation indices than p53 immunonegative tumors. Neither p53 expression nor p21 immunonegativity (52% of AAs and 48% of GBs) correlated with survival. p16 immunostaining was negative in 16% of AAs and in 44% of GBs, and it correlated inversely with survival in both uni- and multivariate analyses. pRb immunostaining was negative only in 8% of both AAs and GBs and the absence of p16 and pRb were mutually exclusive. Ki-67 labelling index (LI) was significantly higher in GBs (26.8%) than in AAs (20.3%), and in multivariate analysis it was an independent prognostic factor for survival. In 48% of AAs Ki-67 LI exceeded 20% and this subset of AAs had similar prognosis as GB. In high grade astrocytic tumors p16 immunonegativity was an independent indicator of poor prognosis in addition to the previously established patient's age, histopathology and Ki-67 LI. Furthermore, there was a subset of AAs with a high proliferation rate (> 20%) in which the histopathological hallmarks of GB were lacking, but which had similarly dismal prognosis as GB.

Clinicopathological features, MIB-1 labeling index and apoptotic index in recurrent astrocytic tumors

This is a study of 64 cases of recurrent astrocytic tumors of all four WHO grades wherein a comparative evaluation of initial vs. recurrent tumor was done with respect to histological grading, MIB-1 labeling index (LI) and apoptotic index (AI). The aim was to identify factor/s that could influence interval to recurrence and/or malignant progression. Recurrence was noted in all grades and upon recurrence, 93.3% of grade II (low grade diffuse) astrocytomas and 63.6% of grade III anaplastic astrocytomas underwent malignant progression. However, none of the Grade I tumors showed evidence of malignant progression. Though interval to recurrence varied considerably, there was a correlation with histological grade of the initial tumor in that grade I and II tumors had a significantly longer mean interval to recurrence (43 months and 54.8 months respectively) as compared to grade III and IV (glioblastoma multiforme) tumors (17.6 and 12.8 months respectively). The interval to recurrence was also longer for grade II and III tumors which showed progression on recurrence (55.3 months for Grade II->Grade III; 54 months for Grade II->Grade IV and 20.6 months for Grade III->IV) as compared to tumors which recurred to the same grade (12.5 months for Grade III->Grade III and 12.8 months for Grade IV->Grade IV). A statistically significant inverse correlation of MIB-1 LI with interval to recurrence was noted. Higher the MIB-1 LI, shorter was the interval to recurrence. Further a cut off MIB-1 LI value of 2.8% could be proposed in predicting recurrence free survival. Interestingly, MIB-1 LI of grade II tumors, which had progressed to grade IV was significantly higher than MIB-1 LI of grade II tumors which had progressed to grade III. Thus, this study establishes the potential role of MIB-1 LI of the initial tumor in determining interval to recurrence. However, apoptotic index has no role in predicting either interval to recurrence or malignant progression.

The challenge of p53 as prognostic and predictive factor in gliomas

In recent years, increasing interest in genetic abnormalities and biologic factors such as the tumour suppressor gene p53 as possible predictive and prognostic factor in gliomas has emerged. Inactivation of p53 can result in resistance to apoptosis, one of the mechanisms thought to explain the failure to respond to DNA-damaging agents. Thus, inactivation of p53 might be associated with a worse prognosis. Considering the inconsistent results of several recent studies, it has remained controversial whether p53 actually can be related to response to treatment and patients' prognosis. Therefore, a systematic review of the literature was performed, which included 28 publications. Techniques for assessing the inactivation of p53 varied widely. Overall, approximately 50% or more of astrocytoma specimens evaluated by immunohistochemistry stained positively for p53, regardless of histologic grade. Eight studies were restricted to comparably treated patients within a single histologic group. In most instances, non-restrictive inclusion criteria and use of statistical methods, which were not sufficient to correct the possible bias, make it difficult to reach unequivocal conclusions. However, it appears that the prognostic information of p53 is at best marginal, especially when compared to established parameters such as grading, age, etc. Its predictive value, which most likely is rather limited too, can hardly be judged without prospective studies also evaluating other biological factors as well as end-points other than time to radiological progression.

Practical value of Ki-67 and p53 labeling indexes in stereotactic biopsies of diffuse and pilocytic astrocytomas

OBJECTIVE

Stereotactic biopsies are increasingly being used for the diagnosis and grading of astrocytomas, and there is a growing need to obtain maximum information from these tissue samples. In everyday practice, p53 protein and Ki-67 immunohistochemical analyses are the most frequently used ancillary studies to aid in diagnosis and grading, but their exact role is not clearly established. This study was undertaken to evaluate the practical value of these markers in stereotactic biopsy samples from diffuse astrocytomas as well as pilocytic astrocytomas. Methods/Results.-We analyzed the Ki-67 (MIB-1) and p53 labeling indexes in the stereotactic biopsy specimens from 11 pilocytic astrocytomas; 8 grade 2, 15 grade 3, and 16 grade 4 diffuse astrocytomas. Pilocytic astrocytomas and diffuse astrocytomas were evaluated as 2 separate groups. There was a strong correlation with poor outcome when both labeling indexes were higher than 15% in the same tumor for diffuse astrocytomas (P < 0.01). The indexes did not correlate with outcome in pilocytic astrocytomas.

CONCLUSION

Combined Ki-67 and p53 labeling indexes higher than 15% indicated a worse outcome than suggested by the histologic grading. The analysis aided or improved histologic evaluation of stereotactic biopsies in our patients. We believe that a realistic prognostic upgrading of diffuse astrocytomas should be made only when labeling indexes for both markers are greater than 15%.

Accumulation of mutant p53(V143A) modulates the growth, clonogenicity, and radiochemosensitivity of malignant glioma cells independent of endogenous p53 status

Alterations of the p53 gene have been attributed a major role in the development and resistance to therapy of several human cancers. Accumulation of p53 in tumor cells may result from mutations associated with prolonged half-life or from stabilization of wild-type p53 by different mechanisms. To address the role of p53 accumulation in the response of malignant glioma cells to radiochemotherapy, we expressed the p53 mutant p53(V143A) in five human malignant glioma cell lines with different genetic and functional p53 status. Accumulation of p53(V143A) modulated proliferation in three and clonogenicity in four of five cell lines without a clear pattern with regard to their endogenous p53 status. p53(V143A) inhibited the camptothecin-induced accumulation of p21(WAF1/CIP1) in cell lines with p53 functional wild-type activity, but not in cell lines lacking p53 activity, consistent with a transdominant-negative effect of p53(V143A). Irradiation induced a moderate G2/M arrest in all cell lines, irrespective of the p53 status, that was unaffected by p53(V143A). Radiosensitivity as well as sensitivity to BCNU, teniposide (VM26), topotecan, vincristine, Taxol, and cisplatin both in cytotoxic cell death and in clonogenic cell death was unchanged in p53(V143A)-transfected cells with few exceptions. These data do not support the hypothesis that accumulation of mutant p53 is a major determinant of the response to adjuvant radiochemotherapy in human malignant glioma cells.

Clinicopathologic study of 85 similarly treated patients with anaplastic astrocytic tumors. An analysis of DNA content (ploidy), cellular proliferation, and p53 expression

BACKGROUND

The biologic behavior of anaplastic (World Health Organization Grade III) astrocytomas and oligoastrocytomas is highly variable, ranging from rapid progression to prolonged survival. It is difficult to predict the outcome of an individual patient based on morphology alone.

METHODS

To determine the prognostic value of commonly used clinicopathologic markers, we reviewed our experience with 85 similarly treated patients enrolled in 3 North Central Cancer Treatment Group high grade glioma protocols. The pathology was comprised exclusively of primary anaplastic astrocytic tumors (66 astrocytomas and 19 oligoastrocytomas). Variables examined included patient age, morphologic type, preoperative performance score, extent of surgery, solitary versus multiple mitoses, DNA flow cytometric and image morphometric parameters, and expression of proliferating cell nuclear antigen, MIB-1, and p53 expression.

RESULTS

The study was comprised of 48 men and 37 women ranging in age from 14-79 years (median age, 47 years). Overall survival ranged from <1 month to >12 years (median, 21.6 months). Statistical analyses revealed that age accounted for the majority of this extensive variability in survival. The median survival times were 65. 5 months, 22.1 months, and 4.4 months, respectively, for the groups <40 years, 40-59 years, and >/=60 years, respectively (P < 0.0001). On univariate analyses, aneuploidy by flow cytometry and a low performance score also predicted a better survival (P values of 0.04 and 0.009, respectively). Statistical trends predicting a better survival were observed for patients with a solitary mitosis and p53 immunopositivity. However, only patient age remained significant in multivariate models.

CONCLUSIONS

In a small but relatively uniformly treated cohort of patients with anaplastic astrocytomas and oligoastrocytomas, patient age was associated strongly and inversely with overall survival. Once patient age was taken into account, the clinical and pathologic markers tested appeared to be of limited prognostic value.

Cell death and oxidative stress in gliomas

In gliomas, apoptosis and necrosis are determined by a number of promoting and inhibiting factors including oxidative cell stress mediated by nitric oxide synthases (NOS) and reduced by superoxide dismutases. Therefore, in 46 gliomas (including astrocytomas, oligodendrogliomas, oligo-astrocytomas, and glioblastomas), the relationship of apoptosis and necrosis and the expression of apoptosis-promoting (p53, bax, Fas, Fas-L) and inhibiting (bcl-2) factors as well as of different isoforms of NOS (NOSb, NOSe, NOSi) and manganese superoxide dismutase (MnSOD) were studied. Apoptosis was measured in situ by the TUNEL method while expression profiles of apoptosis-related and oxidative stress-associated factors were determined by immunohistochemistry. As a defining criterion, necrosis was restricted to glioblastomas while apoptosis increased with tumour malignancy (P=0.017) in all types of gliomas. Glial tumour cells displayed upregulation of bax, Fas, Fas-L, p53, and bcl-2 but with no significant correlation with malignancy. There was also a strong expression of NOS isoforms with upregulation of NOSe in all and of NOSb and NOSi in nearly 50% of the tumour specimens but only NOSb expression correlated significantly with tumour malignancy (P=0.004). Likewise, MnSOD was strongly expressed in all gliomas but was not correlated with tumour grade. There was a wide variability of expression in each tumour type without significant correlation between apoptosis and expression of apoptosis-associated or oxidative stress-related factors indicating that the network of regulating factors may be too complex for clear associations.

p53 protein expression in grade II astrocytomas: immunohistochemical study of 100 cases with long-term follow-up

p53 protein expression was evaluated by immunohistochemistry in a homogeneous series of 100 supratentorial grade II astrocytomas with long-term follow-up. The staining was positive in 72 cases. The proportion of p53 positive tumors was slightly higher in younger patients. The tumor regrowths which derived from p53 positive tumors were themselves p53 positive, and this p53 immunopositivity was often stronger than in the initial tumors. All of the 10 gemistocytic astrocytomas included in our series were p53 positive, and age more than histological type appeared decisive in prognosis. p53 protein expression did not quite reach statistical significance as an independent predictive variable in multivariate analysis, whereas survival was related with age, mass effect, surgery and tumor location. Only a tendency to a longer survival was observed on the curves in younger patients with mildly positive tumors.

Predicting chemoresistance in human malignant glioma cells: the role of molecular genetic analyses

Less than 30% of malignant gliomas respond to adjuvant chemotherapy. Here, we asked whether alterations in the p53 and RB pathways and the expression of six BCL-2 family proteins predicted acute cytotoxicity and clonogenic cell death induced by BCNU, vincristine, cytarabine, teniposide, doxorubicin, camptothecin or beta-lapachone in 12 human malignant glioma cell lines. Neither wild-type p53 status, nor p53 protein accumulation, nor p21 or MDM-2 levels, nor differential expression of BCL-2 family proteins predicted drug sensitivity, except for an association of BAX with higher beta-lapachone sensitivity in acute cytotoxicity assays. p16 protein expression was associated with high doubling time and chemoresistance. We conclude that some important molecular changes, which are involved in the development of gliomas and attributed a role in regulating vulnerability to apoptosis, may not determine the response to chemotherapy in these tumors.

Ki-67 immunolabelling index is a prognostic indicator in childhood posterior fossa ependymomas

Conventional histological evaluation and subclassification of childhood ependymomas poorly predict their biological behaviour. The Ki-67 labelling index (Ki-67 LI), a measure of growth fraction, correlates with the biological behaviour of several neoplasms, and this retrospective study tested the hypothesis that Ki-67 LI is a prognostic indicator in childhood posterior fossa ependymomas. Immunocytochemistry using an antibody to Ki-67 was undertaken on 5 microns sections of formalin-fixed, paraffin-embedded tissue from 74 cases of childhood (age < 16 years.) posterior fossa ependymoma. A Ki-67 LI was established by counting the proportion of labelled nuclei in more than 1000 cells from several histological fields. Several clinical and histological variables (including Ki-67 LI) potentially associated with survival were entered into univariate and multivariate analyses using a Cox proportional hazards model. Variables that showed a significant and independent association with survival were Ki-67 LI (P < 0.002), whether total surgical resection had been achieved according to operation records (P < 0.03), and whether no adjuvant therapy had been given (P < 0.01). Age, sex, and the presence of necrosis or microvascular proliferation did not correlate with survival. In our defined population of patients with ependymomas, Ki-67 LI is a strong prognostic indicator. We recommend that Ki-67 LI is used in the histological evaluation of childhood posterior fossa ependymomas during trials of novel adjunctive therapies.

Accumulation of p53 and Ki-67 expression do not predict survival in patients with fibrillary astrocytomas or the response of these tumors to radiotherapy

OBJECTIVE

Although radiotherapy is often used in the treatment of patients with low-grade astrocytomas, its value is still uncertain. Radiotherapy carries a risk of morbidity for patients and has time and cost implications for health services. We have assessed the value of two histological variables, p53 accumulation and Ki-67 expression, in predicting the response of astrocytomas to radiotherapy. The former antigen was assessed because many astrocytic tumors show mutations in the p53 gene, the function of which is crucial for mediating cell death after radiotherapy, and the latter was assessed because it is expressed only in proliferating tumor cells, which may show greater radiosensitivity than nonproliferating cells.

METHODS

Immunohistochemistry was used to detect the accumulation of p53 and expression of Ki-67 in a retrospective series of 96 patients with supratentorial fibrillary astrocytomas, 58 of whom had received postoperative radiotherapy. The immunohistochemical data were correlated with survival after radiotherapy.

RESULTS

There was no significant difference in survival between the patients who did and those who did not receive radiotherapy. The p53 and Ki-67 labeling indices did not correlate with survival in either the irradiated or the nonirradiated cohort, nor with overall survival in the series as a whole.

CONCLUSION

Immunohistochemical assessment of p53 accumulation and Ki-67 expression does not help in predicting the survival of patients with supratentorial fibrillary astrocytomas or in predicting whether particular patients are likely to benefit from radiotherapy.

BCL-2 family protein expression in human malignant glioma: a clinical-pathological correlative study

Malignant gliomas are rather refractory to current therapeutic approaches including surgery, radiotherapy, chemotherapy and immunotherapy. Acquired alterations in the pathways required for apoptotic cell death are thought to be responsible to the failure of glioma to respond to therapy. Here we have examined the expression of several proteins involved in the susceptibility to apoptosis in 20 human gliomas, including the BCL-2 family proteins BCL-2, BCL-X, BAX and MCL-1, as well as p53 and RB. Most gliomas expressed several BCL-2 family proteins. There was good correlation between expression of the functional antagonists, BCL-2/BCL-X and BAX, suggesting that changes in the BCL-2+BCL-X/BAX ratio are not responsible for the differential response of glioma patients to chemotherapy. The immunochemistry data were also analysed in regard to response to therapy and clinical outcome. All patients had cytoreductive surgery and received radiotherapy and nitrosourea-based adjuvant chemotherapy. There was no prominent association of outcome with the expression patterns of p53, RB, BCL-2, BCL-X or BAX. We find, however, that expression of the MCL-1 protein is associated with early tumour recurrence and shorter survival in this group of glioma patients. This preliminary observation will have to be confirmed in a larger independent sample of glioma patients.

The prognostic significance of Ki-67 labeling indices for oligodendrogliomas

OBJECTIVE

The prognostic significance of quantitative measurement of tumor proliferative activity was evaluated for oligodendroglial tumors.

METHODS

Ki-67/MIB-1 immunochemistry was used to measure proliferative activity in 81 oligodendrogliomas and oligoastrocytomas. The relationship among survival, proliferation, histological features, and clinical variables were evaluated using a Cox proportional hazards analysis.

RESULTS

After stratifying by histological grade and adjusting for age at diagnosis, there was a significant association between the Ki-67/MIB-1 labeling index (LI) (percentage of positive cells) and survival (P = 0.04). This association was illustrated further by the significantly different survival of two groups based on LI ranges of less than or equal to 5 and greater than 5 (P < 0.0001).

CONCLUSION

The poor correlation between mitotic figures and survival in oligodendrogliomas that has been reported previously emphasizes the need for an accurate method to measure proliferative activity. Our study demonstrated the usefulness of the Ki-67/MIB-1 LI and demonstrated that LI ranges can be defined for clinical application.

Demonstration of p53 protein and TP53 gene mutations in oligodendrogliomas

Paraffin embedded tissue of 84 oligodendrogliomas (63 primary tumours, 21 recurrences), 21 glioblastomas with oligodendroglial growth pattern (15 primaries, 6 recurrences) and 17 mixed gliomas was investigated for the presence of mutations in exons 5-9 by means of single stranded conformation polymorphism (SCCP), temperature gradient gel electrophoresis (TGGE) and direct DNA sequencing. In parallel, p53 protein accumulation was determined by means of immunohistochemistry. The percentage of mutations was found to be higher than previously reported (6 of 44 grade II oligodendrogliomas, 4 of 19 grade III oligodendrogliomas, 4 of 15 glioblastomas). In 4 cases, the mutations lead to distinct changes in the primary or secondary structure of the protein (cysteine-->tyrosine, proline-->leucine) and were associated with marked accumulation of p53 protein. A significant correlation between p53 protein accumulation and TP53 gene aberrations was found (P < 0.001), although p53 protein accumulation was detected more often than TP53 gene anomalies, indicating that factors other than TP53 gene mutation may also lead to a p53 protein accumulation in the tumour cells. A significant correlation was found for p53 protein accumulation and tumour grade but not TP53 gene mutations. In conclusion, evaluation of p53 protein accumulation reflected the clinical course of oligodendrogliomas better than the mere presence of TP53 gene mutations.

Cell kinetic analysis in recurrent neuro-epithelial tumours

The biological behaviour of brain tumours is variable. In the majority of cases, recurrence of the tumour is the decisive factor determining the prognosis and individual survival of patients suffering from a neuro-epithelial neoplasm. The time course of recurrences varies significantly according to differences in tumour cell proliferation. In this study, predictive factors concerning the expected prognosis following the resection of neuro-epithelial tumours were investigated with the aim of improving the histological diagnosis. A retrospective analysis of 22 recurrent neuro-epithelial tumours (recurrent tumour group) and 12 neuro-epithelial tumours with a minimum survival rate of 5 years following radical excision (cured tumour group) was performed by means of flow cytometry and immunohistochemistry using the MIB 1 antibody. Histological samples of the subgroups of the recurrent tumour group, i. e., the primary tumours and their recurrences were compared with each other, and the subgroups were compared with the cured tumour group. A multivariate analysis of the data was performed with the BMPD Hotteling T square test. A statistically significant difference was found between the recurrent tumour group (primary tumours + recurrences) and the cured group from every investigated aspect. On the other hand, no difference could be found between the sub-groups primary tumours and their recurrences. All tumours in the recurrent group had an accelerated, active cell cycle, which was expressed in a high proliferation activity. The following conclusion was drawn: an increased risk of recurrence is to be expected in neuro-epithelial tumours characterized by: an S-phase fraction higher than 6-9%, an MIB 1-labelled cell number higher than 2-3/high-power fields, and a number of mitoses higher than 1/10 high-power fields.