Flow-cytometric DNA analysis and immunohistochemical measurement of Ki-67 and BUdR labeling indices in human brain tumors

The Past, Present and Future of Flow Cytometry in Central Nervous System Malignancies

Central nervous system malignancies (CNSMs) are categorized among the most aggressive and deadly types of cancer. The low median survival in patients with CNSMs is partly explained by the objective difficulties of brain surgeries as well as by the acquired chemoresistance of CNSM cells. Flow Cytometry is an analytical technique with the ability to quantify cell phenotype and to categorize cell populations on the basis of their characteristics. In the current review, we summarize the Flow Cytometry methodologies that have been used to study different phenotypic aspects of CNSMs. These include DNA content analysis for the determination of malignancy status and phenotypic characterization, as well as the methodologies used during the development of novel therapeutic agents. We conclude with the historical and current utility of Flow Cytometry in the field, and we propose how we can exploit current and possible future methodologies in the battle against this dreadful type of malignancy.

Proliferating Cell Nuclear Antigen Immunoreaction in Adrenal Tumors

Aims and background

We studied, retrospectively, 33 cases of adrenal tumors of children at the Pediatric Endocrinology Unit, Children's Institute, São Paulo State University Medical School, from 1975 to 1993. All patients had at least 2 years of follow-up with a few exceptions.

Methods

Clinical follow-up data were correlated with histopathologic review, laboratory data and cell kinetic evaluation (based on detection of proliferating cell nuclear antigens).

Results

With one exception, all the patients had presented signs of androgen production and had high levels of dehydro-epiandrosterone-sulfate. Tumor weight evaluation represented a good parameter of neoplasm evolution: of 19 cases weighing less than 250 g, 17 had no evidence of disease after surgery, and 2 had an unfavorable prognosis. Of 14 cases weighing more than 250 g, only 1 had no evidence of disease and 13 had an unfavorable evolution.

Conclusions

Proliferating cell nuclear antigen (PCNA) was not helpful to evaluate adrenal neoplasm evolution: our study did not show any correlation between PCNA score and prognosis.

1q/19p co-polysomy predicts longer survival in patients with astrocytic gliomas

Recently, we reported that 1q/19p co-polysomy predicted poor prognosis in oligodendroglial tumors. In this study, we aimed to retrospectively analyze the prognostic significance of 1q/19p polysomy in two large cohorts of astrocytic gliomas classified by the 2007 and 2016 WHO classification of tumors of the central nervous system. 1q/19p polysomy was detected using the FISH method, and factors that correlated with polysomy were analyzed by logistic regression. Survival analysis was used to identify independent prognostic factors correlated with survival. In the WHO₂₀₀₇ astrocytic glioma cohort (N=421), co-polysomy was associated with a younger age, whereas single polysomy was associated with higher tumor grades and a higher Ki-67 index (P<0.05). Co-polysomy predicted longer survival, and single polysomy predicted shorter survival (P<0.05). In multivariate analysis, co-polysomy maintained an independent prognostic impact on survival (P=0.001) after adjustment for age, KPS, grade, removal degree, tumor size, Ki-67 index, and IDH1/2. In the WHO₂₀₁₆ cohort (N=572), we validated the prognostic merit of co-polysomy after adjusting for related factors. In conclusion, 1q/19p co-polysomy added prognostic information in cases of astrocytic glioma and could be used for molecular stratification of this disease.

Pituitary carcinoma

The presence of distant metastases may be asymptomatic in patients who present with symptoms and signs due to the local mass effects of an invasive pituitary adenoma. A case of pituitary carcinoma in a 54-year-old man who presented with widespread asymptomatic distant metastases 12 years after initial diagnosis is reviewed. The long course and asymptomatic metastases suggested a relatively slow-growing malignancy. The factors that played a role in the pathogenesis of the metastasis are unknown. A review of the literature on pituitary carcinoma suggests that accurate diagnosis and a multidisciplinary approach to management of such lesions emphasizing surgery, radiotherapy, and hormonal manipulation may provide these patients with the longest and best quality of survival.

Cellular DNA content parameters as prognostic indicators in human astrocytomas

OBJECTIVE

Clinical parameters such as grade, size and/or location of the tumor are good predictors of outcome in patients with astrocytoma. The objective of this study was to determine whether DNA content parameters have a prognostic significance for this group of tumors.

METHODS

Following optimization and validation of methodology for evaluating cellular DNA content parameters (CDCP), tumor DNA ploidy and percent S phase fraction (SPF) were determined from 64 patients using formalin fixed, paraffin embedded specimens (mean coefficient of variation=4.94) obtained over a 10-year period. Median survival times correlated with grade (I/II=1154 vs. III/IV=483days, P=0.0317). Fifty-five percent of the specimens contained DNA aneuploid (DNA-A) components (average SPF=18.3%) and 45% were DNA diploid (DNA-D) (average SPF=9.6%). Survival did not correlate with overall differences in DNA ploidy (DNA-D=181 vs. DNA-A=206days, P=0.6314) when treated and untreated tumors were analyzed. However, a trend for prolonged median survival was observed in patients whose tumors were untreated with respect to cytotoxic therapy based on DNA ploidy status (DNA-D=275 vs. DNA-A=15days, P=0.3408). Survival for all patients did not correlate with median SPF (<13.5% av.=121 vs. >13.5% av.=154days, P=0.6534).

CONCLUSION

DNA content parameters may correlate with the natural history and treatment outcome of newly diagnosed untreated patients with astrocytomas.

PCNA and Ki-67 in central nervous system tumors: correlation with the histological type and grade

Determination of proteins in the control of proliferation in normal cells helps a better understanding of cellular transformation and proliferation mechanisms. Measurement of proliferative activity is important in determining the tumor grade, recurrence span and malignancy. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two of the nuclear markers used to demonstrate the proliferative phase of the cell cycle. In the present study, 63 central nervous system (CNS) tumors of various histologic types, diagnosed in Cukurova University Medical Faculty. Department of Pathology and graded according to WHO grading system were examined for PCNA and Ki-67 monoclonal antibodies using immunohistochemistry. Results were analyzed with statistical methods. Distribution of PCNA and Ki-67 LI (labeling index) values were determined for different tumor types. The highest PCNA and Ki-67 LI values were detected in medulloblastoma, malignant meningioma, primitive neuroectodermal tumor (PNET) and glioblastoma (GBM) groups, while pilocytic astrocytoma, meningioma, craniopharyngioma and oligodendroglioma showed the lowest values. In such tumors, the correlation between the increasing grade and PCNA and Ki-67 LI values were statistically significant. A correlation between the clinical outcome and Ki-67 and PCNA LI values was also detected. Conclusively, both markers can be used to evaluate the tumor grade and to asses the possibility of recurrence and malignancy in CNS tumors.

Detection of proliferating S-phase brain tumor cells by in situ DNA replication

OBJECT

Current methods used to describe the proliferative status of brain tumors rely on labor-intensive, potentially costly procedures. This article provides a description of a rapid, inexpensive, uncomplicated technique used to identify proliferating cells in tissue obtained at the time of resection.

METHODS

Touch preparations of 16 fresh astrocytic tumors and four fresh healthy temporal neocortical tissue samples were obtained at the time of surgery. Slides were placed in hypotonic potassium chloride to permeabilize their membranes, incubated in nucleotide precursors, and labeled with bromodeoxyuridine; they were later examined with the aid of a fluorescence microscope. The percentage of tumor cells in the S phase increased in conjunction with the grade of tumor and corresponded with the findings of immunohistochemical staining for the cell-cycle marker MIB-1. These results were confirmed in cell culture by using normal human astrocytes and two glioma cell lines. Slides can be analyzed in as little as 30 minutes after removal of tissue during surgery.

CONCLUSIONS

In this study the authors describe a simple method by which cells in the S phase of the cell cycle. which are contained in fresh tumor obtained at the time of surgery, can be labeled. This method may prove a useful adjunct to frozen-section analysis and may permit discrimination of neoplastic tissues from other tissues observed in small specimen samples.

Intracranial meningeal tumours in childhood: a clinicopathologic study including MIB-1 immunohistochemistry

Primary tumours of the meninges with a relatively high tendency for malignant behaviour are uncommon in childhood. This study concerns 18 cases of meningeal tumours in children under the age of 16, of which 13 were meningiomas and five were other tumours arising in the meninges. Meningiomas showed a preponderance in females as in adult series, and the majority were supratentorial in localisation. The percentage of meningeal tumours and meningiomas among all brain tumours in our centre were 3.72% and 2.69%, respectively. Four out of 13 meningiomas were fibroblastic, four were transitional, one was meningothelial, two were psammomatous and two were papillary meningiomas. Seven (38.8%) out of 18 tumours showed anaplastic features, including two papillary meningiomas, two hemangiopericytomas, one mesenchymal chondrosarcoma, one pleomorphic sarcoma and one anaplastic meningeal tumour. Papillary meningiomas with hemangiopericytoma-like solid areas were seen frequently in our cases (15.3%). Meningoangiomatosis was associated with two meningeal tumours. MIB1 (Ki-67) labelling indices (LIs) ranged between 0% and 13.6% (mean 1.83%) in benign, and between 1% and 20% (mean 7.2%) in malignant tumour, including papillary meningiomas. Mean MIB-1 LIs were 5.61% and 1.14% in non-recurrent and recurrent cases, respectively. MIB-1 LIs showed significant differences between benign and malignant meningeal tumours but no significant correlation either with prognosis or recurrence. Despite the fact that brain tumours are among the most common neoplasms of childhood, meningeal tumours are rare lesions, accounting for less than 2% of published series of intracranial neoplasms in childhood [5, 8, 18, 24, 30, 32]. It has been suggested that the clinical and pathological characteristics of meningiomas in this age group differ from those of adults [14, 18, 24, 45]. Besides meningiomas, there are a few reports of other meningeal tumours in childhood and difficulties in differential diagnosis may arise within this group, especially in anaplastic tumours [11, 13, 32, 44, 46]. One of the major problems in meningiomas and some tumours arising in the meninges is the discordance that arises between the histologic appearance of the tumour and behaviour [4]. Several studies have attempted to determine the proliferation potential of meningiomas, including immunohistochemical labelling with monoclonal antibodies to Ki-67, proliferating cell nuclear antigen (PCNA), and bromodeoxyuridine (BUdR); flow cytometric DNA analysis; or argyrophilic nucleolar organizer regions (AgNORs) counting [9, 10, 15, 19, 22, 26, 31, 35, 53]. The studies concerning proliferation markers have contradictory results [9, 10, 15, 26, 31, 42, 53]. MIB-1 detects the same or a similar epitope as the original antibody Ki-67 and reacts with a proliferation associated antigen expressed in all active parts of the cell cycle, G1, S, G2 and M (mitosis), but not in the G0 or quiescent phases [7]. In this study we examined the clinicopathological characteristics and MIB1 values of 18 meningeal tumours in children under the age of 16 years within the last 25 years (from 1970 to 1995).

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.

Are markers of proliferation valuable in the histological assessment of pituitary tumours?

The prediction of tumour behaviour and response to treatment has led to interest in the assessment of the proliferative potential of tumours. Pituitary tumours are usually histologically benign but are capable of aggressive growth and local invasion, although distant metastasis is limited to the very rare pituitary carcinoma. These differences in tumour behaviour may determine both the prognosis and also the effectiveness of treatment whether it be surgery, drugs or radiotherapy. Immunohistochemistry using antibodies to Ki-67 and proliferating cell nuclear antigen (PCNA) which are expressed in cells that have entered the cell cycle, can be used to assess the proportion of the cells from a tumour that are proliferating. The percentage of positively stained nuclei (labelling index (LI)) may be helpful in predicting appropriate management, as there is a relationship in many tumours between labelling index, invasiveness and tumour recurrence. This has been shown to be true for pituitary tumours, although there may be significant overlap such that low LI may be seen in the rare, aggressive, metastatic pituitary carcinomas, and high LI in indolent tumours. Thus although assessment of proliferation may be helpful in arousing suspicion as to subsequent tumour recurrence or invasiveness, this technique also demonstrates that there are other important and as yet unidentified processes that determine pituitary tumour behaviour.

Supratentorial ependymomas in adult patients

OBJECTIVE

Ependymomas arise from different areas in the neuraxis and have variable outcomes that depend on tumor location and patient age at the time of presentation. The predictive value of histology for these tumors is unresolved. We report a series of adult patients with supratentorial ependymomas to characterize the roles of surgery, histology, ploidy, and proliferation index in tumor control.

METHODS

Fourteen of the 23 supratentorial ependymomas were in the region of the third ventricle and the remainder were located in the hemispheres. Resections were gross total in 12 patients, subtotal in 8, and biopsy in 3. A single pathologist reviewed all slides and quantitated the deoxyribonucleic acid. The mean follow-up duration was 95 months (+/-75 mo).

RESULTS

All of the malignant ependymomas were hemispheric (n = 4). Mortality occurred only in patients with third ventricular tumors; two patients died as a result of surgical complications and three as a result of tumor progression. Kaplan-Meier estimates of 5- and 10-year survival rates were 100% for hemispheric and 72.5% for third ventricular tumors (62.5% including the two perioperative deaths). The median time to recurrence was 53 months, with a 10-year progression-free survival rate of 27%. Univariate analysis revealed that recurrence was associated with malignant histology, including mitoses, cellularity, and aneuploidy. For nonmalignant ependymomas, recurrence was associated with subtotal resection and metastases. S-phase fraction did not correlate with recurrence. Only malignant histology correlated with recurrence on multivariate analysis.

CONCLUSION

Although the numbers are too small to draw any definite conclusions, treatment of ependymomas that arise in the supratentorial compartment in adult patients results in excellent outcomes despite frequent recurrences. Association with the third ventricle and metastases seem to have a negative impact on survival, whereas malignant histology, subtotal resection, and metastases may be predictors of recurrence.

MIB-1 labeling index in nonpilocytic astrocytoma of childhood: a study of 101 cases

BACKGROUND

The prognosis of pediatric patients with nonpilocytic astrocytoma, and in particular those with anaplastic astrocytoma, is somewhat unpredictable. This study used MIB-1 monoclonal antibody, a proliferative marker that can be used in formalin fixed paraffin embedded tissues, to study nonpilocytic pediatric astrocytoma.

METHODS

Astrocytoma, anaplastic astrocytoma, and glioblastoma specimens excised from a total of 101 pediatric patients during the period from January 1975 to September 1996 were retrieved from the authors' surgical pathology file. Histologic grading of the specimens was performed based on a modified Ringertz system. The proliferative potential of the tumors was estimated by using the MIB-1 labeling index (LI), which was evaluated with morphologic grades of tumors and survival of the patients.

RESULTS

Of the 101 patients, 34 had astrocytoma, 33 had anaplastic astrocytoma, and 34 had glioblastoma. Their mean survival times were 165.2+/-14.9 months (mean+/-standard error; SE), 46.1+/-9.9 months, and 21.8+/-5.6 months, respectively. The mean MIB-1 LI of different tumor grades were as follows: astrocytoma, 3.9+/-4.3 (mean+/-standard deviation; range, 0.0-21.6); anaplastic astrocytoma, 24.3+/-15.6 (range, 1.7-62.8); and glioblastoma, 35.9+/-16.4 (range, 7.36-63.3). The mean survival of the entire group of patients with LIs < or = 11 was 173.2+/-12.2 months (mean+/-SE), and the mean survival of those with LIs > 11 was 20.3+/-4.1 months. The survival of anaplastic astrocytoma patients with LIs < or = 11 was similar to that of astrocytoma patients, whereas the survival of anaplastic astrocytoma patients with LI > 11 was similar to that of patients with glioblastoma.

CONCLUSIONS

The results of the current study show that histopathologic grading can predict the outcome for patients with astrocytomas and glioblastomas, whereas MIB-1 LI can separate better and worse prognostic groups in patients with anaplastic astrocytoma.

Current concepts in neuro-oncology: the cell cycle--a review

Uncontrolled cellular proliferation is the hallmark of human malignant brain tumors. Their growth proceeds inexorably, in part because their cellular constituents have an altered genetic code that enables them to evade the checks and balances of the normal cell cycle. Recently, a number of major advances in molecular biology have led to the identification of several critical genetic and enzymatic pathways that are disturbed in cancer cells resulting in uncontrolled cell cycling. We now know that the progression of a cell through the cell cycle is controlled in part by a series of protein kinases, the activity of which is regulated by a group of proteins called cyclins. Cyclins act in concert with the cyclin-dependent kinases (CDKs) to phosphorylate key substrates that facilitate the passage of the cell through each phase of the cell cycle. A critical target of cyclin-CDK enzymes is the retinoblastoma tumor suppressor protein, and phosphorylation of this protein inhibits its ability to restrain activity of a family of transcription factors (E2F family), which induce expression of genes important for cell proliferation. In addition to the cyclins and CDKS, there is an emerging family of CDK inhibitors, which modulate the activity of cyclins and CDKs. CDK inhibitors inhibit cyclin-CDK complexes and transduce internal or external growth-suppressive signals, which act on the cell cycle machinery. Accordingly, all CDK inhibitors are candidate tumor suppressor genes. It is becoming clear that a common feature of cancer cells is the abrogation of cell cycle checkpoints, either by aberrant expression of positive regulators (for example, cyclins and CDKs) or the loss of negative regulators, including p21Cip1 through loss of function of its transcriptional activator p53, or deletion or mutation of p16ink4A (multiple tumor suppressor 1/CDKN2) and the retinoblastoma tumor suppressor protein. In this review, we describe in detail our current knowledge of the normal cell cycle and how it is disturbed in cancer cells. Because there have now been a number of recent studies showing alterations in cell cycle gene expression in human brain tumors, we will review the derangements in both the positive and negative cell cycle regulators that have been reported for these neoplasms. A thorough understanding of the molecular events of the cell cycle may lead to new opportunities by which astrocytoma cell proliferation can be controlled either pharmacologically or by gene transfer techniques.

Analysis of proliferation markers and p53 expression in gliomas of astrocytic origin: relationships and prognostic value

Consecutive paraffin sections of 105 astrocytomas and 15 oligoastrocytomas were examined for expression of p53, MIB-1 (Ki-67), and proliferating cell nuclear antigen (PCNA). The tumors had been examined previously for genetic abnormalities and by flow cytometry. Regardless of the tumor's stage and grade and the patient's age and gender, p53 expression was found in 40% of tumors. Although p53 expression was associated with a loss on chromosome 17p and was more frequent in aneuploid tumors, it had no association with survival time. The MIB-1 and PCNA labeling indices increased with increasing tumor grade but showed no association with other clinicopathological parameters. In individual tumors, there was poor concordance between any of the variables (MIB-1, PCNA, and p53). Results for p53 and MIB-1 were similar for both astrocytomas and oligoastrocytomas. The MIB-1 and PCNA values appeared to have prognostic utility in univariate analysis but not after adjusting for patient age and tumor grade. The poor concordance between MIB-1 and PCNA in individual tumors indicates that any one means of assessing proliferative potential in gliomas may not be reliable.

DNA ploidy and S-phase in recurrent astrocytomas: a retrospective study by flow cytometry of deparaffinized specimens

Twenty-two patients with recurrent astrocytic tumors were treated surgically two or even three times. At the time of the first surgery 6 tumors were fibrillary astrocytomas (grade II), 9 anaplastic astrocytomas (grade III) and 7 glioblastomas (grade IV). Histopathological specimens from second surgery demonstrated in 12 cases signs of higher grades of malignancy. Flow cytometry (FCM) did not reveal any significant changes of S-phase fraction (p = 0.55). This study supports the theory that, given enough time, the histopathology of brain tumors change significantly from more benign forms to more malignant ones. The flow cytometry (FCM) could trace a weak tendency to higher S-phase fractions at the time of the second surgery. No apparent change of ploidy pattern was observed. In spite of the unequivocal histopathological changes of the recurrent astrocytomas the flow cytometry failed to indicate similar changes in terms of ploidy and S-phase fraction parameters.

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.

MIB-1 staining index and peritumoral brain edema of meningiomas

BACKGROUND

Growth rates and tumor aggressiveness of meningiomas are thought to be closely related to brain edema development. However, histopathologic data alone are not consistently accurate predictors of the behavior and clinical course of a meningioma.

METHODS

The authors examined 57 histologically proven intracranial meningiomas to identify factors, including growth fractions determined by MIB-1 immunostaining, that may influence the development of meningioma-associated peritumoral brain edema. There were 54 benign, 2 atypical, and 1 anaplastic meningiomas. The MIB-1 staining index (SI) percentage was defined as the number of MIB-1 positive cells divided by the total number of tumor cells in a 1.037-square millimeter area on the slide. The extent of peritumoral brain edema was determined using preoperative magnetic resonance imaging. The extent of edema was classified as Grade 0,1, or 2 (GR0, GR1, or GR2), in order of increasing severity.

RESULTS

The MIB-1 SIs of the 57 cases ranged from 0.06-6.8% (median, 0.80%). There were 26 GR0, 20 GR1, and 11 GR2 edema cases. The MIB-1 SI rose in order of increasing edema severity. There was a statistically significant correlation between the MIB-1 SI and the extent of brain edema (P<0.0001), and also between the tumor size and the extent of brain edema (P=0.001). Meningothelial and atypical/anaplastic meningiomas were associated with peritumoral brain edema more often than any other subtype (P<0.005).

CONCLUSIONS

Growth fractions, as determined by MIB-1 immunostaining, rise with increasing severity of peritumoral brain edema, indicating a close relationship between tumor aggressiveness and edema development.

Comparison of MIB-1 (Ki-67) antigen and bromodeoxyuridine proliferation indices in meningiomas

Meningiomas from 40 adult patients were labeled immunohistochemically with monoclonal antibodies to bromodeoxyuridine (BUdR) and the Ki-67 antigen, MIB-1. The meningiomas were classified as classical, or benign (n = 31); atypical (n = 4); or malignant (n = 5). Meningeal sarcomas and hemangiopericytomas were excluded. The patient population consisted of 26 women and 14 men, ranging in age from 26 to 75 years. BUdR proliferation indices ranged from 0% to 5.8%, measurements that were expectedly lower than those for MIB-1, which ranged from 1.5% to 19.3%. MIB-1 proliferation indices were not significantly affected regarding steroid pretreatment or age. These results show a good correlation between the BUdR and MIB-1 proliferation markers (rs = 0.72; P < .0001), which supports the use of anti-MIB-1 as an alternative labeling tool to BUdR for the determination of the proliferation index in meningiomas, thus avoiding the administration of a potentially mutagenic drug.

The correlation of Ki-67 staining indices with tumour doubling times in regrowing non-functioning pituitary adenomas

In order to improve our ability to predict the regrowth of nonfunctioning pituitary adenomas, we tried to assess the correlation between growth fractions with Ki-67 and PCNA (proliferating cell nuclear antigen) and tumour doubling times in regrowing tumours, and also to find out any difference of growth fractions between the regrowing and the cured cases. In 33 patients with non-functioning pituitary adenomas, 14 cases including 11 with cavernous sinus invasion showed residual tumour on MRI after the operation (regrowing group) and 19 cases had no tumour regrowth on MRI within 5 years after the operation (cured group). Immunocytochemical studies were done with monoclonal antibodies (anti-PCNA, anti-Ki-67: MIB-1). The growth fraction of each tumour was estimated by calculating the ratio of the positive nuclei to the total number of tumour cells with the aid of an image analyser (Mac SCOPE). The tumour doubling times were estimated from serial CT or MRI with the aid of the image analyser (NIH image). Ki-67 staining indices ranged from 0.2% to 1.5% (n = 14, 0.86 +/- 0.10%; mean +/- SEM) in the regrowing group, and from 0.1% to 0.5% (n = 19, 0.23 +/- 0.03%) in the cured group. PCNA staining indices of the regrowing group ranged from 0.6% to 24% (n = 14, 3.7 +/- 1.6%). In the regrowing group, the tumour doubling times ranged from 200 to 2550 days (930 +/- 180 days), and showed a significant inverse correlation with Ki-67 staining indices, but no correlation with PCNA staining indices. The regrowing group showed a significantly higher Ki-67 staining index (n = 14, 0.86 +/- 0.10%) than the cured group (n = 19, 0.23 +/- 0.03%) (p < 0.01). These results indicate that immunocytochemical studies using MIB-1 may be better than those with PCNA for the prediction of regrowth in non-functioning pituitary adenomas. Immunocytochemical study with MIB-1 could lead to the accurate prediction of the rapid regrowing lesions in non-functioning adenomas.

Nuclear morphometry and DNA densitometry of human gliomas by image analysis

In 48 patients with gliomas in whom complete clinical follow-up was obtained, DNA ploidy was evaluated by using formalin-fixed paraffin-embedded tissues and by means of image analysis. The mean DNA indices, determined by averaging DNA indices of all tumor cells in a tumor, were mainly affected by mean DNA indices of the nuclei of SG2M phase tumor cell (including S phase and G2M phase cells) (SG2M DNA indices) and that mean DNA indices correlated with the SG2M phase fraction. The SG2M DNA indices and the percentage of tumor cells with S phase and G2M phase were higher in high grade gliomas including anaplastic glioma and glioblastoma multiforme than in low grade gliomas. Patients with G2M-hypertetraploid tumors demonstrated a shorter time to tumor progression than those with G2M-tetraploid in high grade glioma. Morphometrically, the nuclei of SG2M phase glioma cells were larger and more deformity than those of G0G1 phase (including G0 phase and G1 phase cells) cells. The G2M-hypertetraploid tumors were highly malignant and demonstrated large nuclei, greater nuclear deformity, and a higher proliferative potential. The G2M-tetraploid gliomas demonstrated a shorter time to tumor progression in cases whose the SG2M fraction was large. In contrast, G2M-hypotetraploid gliomas revealed an insignificant trend towards a longer time to tumor progression than those associated with tetraploid and hypertetraploid gliomas. We emphasize herein the prognostic importance of the SG2M phase cell, as well as other proliferation indices.

Aberrant p53 expression does not correlate with the prognosis in anaplastic astrocytoma

Mutations of the p53 tumor-suppressor gene, as determined by the immunohistochemistry of archival formalin-fixed specimens, have been correlated with the prognosis for patients with many different types of malignancy. Similar correlations have been shown in series including patients with all grades of astrocytoma. We hypothesized that this might be a clinically useful prognostic indicator for patients with a defined grade of astrocytoma, anaplastic astrocytoma. This series comprised 54 consecutive patients with biopsy-proven anaplastic astrocytoma treated at one institution. When the CM-1 antiserum was used for testing, 33 (61%) of the 54 biopsies exhibited positive nuclear staining for p53, indicating an abnormal accumulation of the protein. This staining was graded according to the number of positive cells per high-power field. Positive immunohistochemical staining for p53 in the tumor cell nuclei did not correlate with the patient's outcome. Significant correlates of improved patient survival were the presentation with epilepsy in the absence of a neurological deficit (P = 0.005) and the surgeon's performance of a macroscopically complete surgical resection of the tumor (P = 0.01).

The comparison between the growth fraction of bilateral vestibular schwannomas in neurofibromatosis 2 (NF2) and unilateral vestibular schwannomas using the monoclonal antibody MIB 1

Formalin-fixed paraffin sections of 55 consecutive bilateral vestibular schwannomas in 46 patients with neurofibromatosis 2 (NF2), and 50 patients with unilateral vestibular schwannomas were investigated immunohistochemically with the monoclonal antibody MIB 1 directed against recombinant parts of Ki-67 antigen. The immunohistochemical staining was carried out on dewaxed microwave oven-processed paraffin sections of formalin-fixed tumour tissues. The labelling index (LI) obtained was compared to clinical and histological findings in both groups. There was no correlation between the LI and age of the patients, tumour size, or histological type of tumour (Antoni A or B). Vestibular schwannomas in NF2 showed higher LI than unilateral vestibular schwannomas: the maximal LI found per section (LI max) ranged from 0.4 to 17.6% (mean, 2.7%) in NF2 schwannomas, and from 0 to 9% (mean, 2.2%) in unilateral schwannomas. These differences may express immunohistochemically some clinical and morphological differences between bilateral and unilateral vestibular schwannomas.

Proliferative activity of acoustic neurilemomas without neurofibromatosis determined by monoclonal antibody MIB 1

Microscopic sections obtained from paraffin blocks of 30 consecutive neurilemomas stored in 1989 were investigated immunohistochemically with the new monoclonal antibody MIB 1 directed against recombinant parts of Ki-67 antigen. The immunohistochemical staining was carried out on dewaxed microwave-oven-processed paraffin sections of formalin-fixed tumour tissues. The labelling index (LI) obtained was below 1% in 21 cases, 1-3% in 7 cases and more than 3% in 2 cases. There was no correlation between the LI and the age of the patients or the tumour size. The major advantage of MIB 1 over previous immunohistochemical methods is its usefulness in long preserved sections which are ideal for retrospective studies.

A correlative study of in vivo and in vitro labeling index using bromodeoxyuridine in human brain tumors

The labeling index (LI) of 216 cases of human brain tumors was determined by the immunohistochemical technique with monoclonal antibody to bromodeoxyuridine (BrdU). The proliferative potential of 110 cases was estimated using the intra-operative intravenous infusion of BrdU at a dose of 200 mg/sq m. In another 106 cases, the in vitro technique of incubating freshly resected tumor tissue fragments with 100 microM bromodeoxyuridine was used. The BrdU LI in these tumors was then correlated with the histological types and the data as determined by both the in vivo and in vitro BrdU incorporation were compared. The results indicate that although in vivo and in vitro techniques could possibly provide equivalent data in some histologic types, a clear statistically valid proof however is not apparent from this study.

Correlation between the bromodeoxyuridine labeling index and the MIB-1 and Ki-67 proliferating cell indices in cerebral gliomas

BACKGROUND

Recently, it has been shown that heating paraffin embedded tumor sections in a microwave oven can reactivate an epitope of Ki-67 protein that is recognized by the monoclonal antibody MIB-1. With this technique, a close correlation was shown between the bromodeoxyuridine labeling index (BUdR LI) and the MIB-1 proliferating cell index (PCI) in corresponding regions of glioblastomas.

METHODS

The reliability of the MIB-1 PCI as a marker of proliferation was evaluated in 90 cerebral gliomas. The MIB-1 immunostaining of ethanol-fixed, paraffin embedded sections of 23 moderately anaplastic astrocytomas, 22 highly anaplastic astrocytomas, 30 glioblastomas, and 15 mixed malignant gliomas was compared with the BUdR LI and, in some cases, the Ki-67 PCI.

RESULTS

MIB-1 positive cells were detected easily in the majority of the cases, and the MIB-1 immunostaining was often superior to that of Ki-67 in individual tumors. The MIB-1 PCI was significantly higher than the Ki-67 PCI and the BUdR LI. Linear-regression analysis showed significant correlations among the three indices. The MIB-1 PCI was correlated with the BUdR LI in each group of the astrocytic tumors and mixed malignant gliomas; the MIB-1 PCI was approximately 2.4-2.8 times higher than the BUdR LI.

CONCLUSIONS

The close correlation between the MIB-1 PCI and the in vivo BUdR LI in serial sections of glioma subtypes suggests that MIB-1 immunostaining is a useful technique for analyzing the proliferative potential of individual gliomas.

Prognostic factors in gliomas. A multivariate analysis of clinical, pathologic, flow cytometric, cytogenetic, and molecular markers

BACKGROUND

The ability to divide subsets of patients with glial neoplasms into prognostic groups currently is limited because only a few clinical and pathologic variables are available. The goal of this investigation was to identify biologic factors of potential prognostic value in patients with cerebral gliomas.

METHODS

This prospective investigation used clinical, pathologic, flow cytometric, cytogenetic, and molecular genetic variables as potential prognostic factors in 207 patients with newly diagnosed gliomas (153 astrocytic tumors of the fibrillary type, 31 oligodendrogliomas, and 23 pilocytic astrocytomas). Classification and regression tree (CART) analysis was performed as part of the multivariate statistical analysis.

RESULTS

The age of the patient and the grade of the tumor were confirmed as strong prognostic factors. Cytogenetic or molecular genetic abnormalities of chromosomes 7 and 10 were associated with poor survival in univariate analysis (P < 0.0001). CART multivariate analysis identified several subsets of patients with different prognoses. In the subset of patients younger than 66.5 years with Grade 4 tumors, the survival time was longer for those with aneuploid tumors than for those with nonaneuploid tumors. In the subset of patients with Grades 1-3 tumors, the survival time was longer for those whose tumors had a %G2M of less than 6.9 than for those whose tumors had a %G2M of 6.9 or greater.

CONCLUSION

This investigation provides further evidence that flow cytometry, cytogenetic, and molecular genetic factors that may have prognostic value in patients with gliomas can be identified.

Prognostic significance of bromodeoxyuridine labeling in primary and recurrent glioblastoma multiforme

To evaluate the prognostic significance of bromodeoxyuridine (BUdR) labeling index (LI) and to estimate tumor proliferative potential, BUdR LI was examined in 98 patients having a primary diagnosis of glioblastoma multiforme (GBM); 55 underwent infusion of 200 mg/m2 of BUdR at the time of the primary resection and 49 underwent infusion at the time of the second resection. The tumors of six patients were labeled at both operations. The tumor specimens were stained with hematoxylin and eosin for histopathology and by immunohistochemical methods to determine the ratio of labeled to unlabeled cells, i.e., BUdR LI. The median BUdR LIs for the primary and recurrent GBM were significantly different at 6.8 and 2.6%, respectively (P < 0.0001). However, there was no significant association between BUdR LI at the first or second operation and survival (log rank, P = 0.12; Cox regression analysis, P = 0.91; log rank, P = 0.55; Cox regression analysis, P = 0.17, respectively). Patients who underwent a second operation within 10 months of the first operation had a lower BUdR LI than did patients with a longer interval between procedures (P = 0.078; Spearman rank correlation, 0.26). The aggressive biological behavior of GBM is dependent on complex cellular kinetics, not simply on the number of cells within the S phase of the cell cycle. Caution should be used when determining prognosis with BUdR LI in GBM.

DNA amplifications and elevated expression of proto-oncogene in addition to altered DNA ploidy in metastatic brain tumors

The histopathological characteristics, proto-oncogene amplification, immunohistopathology of the c-erbB-2 product distribution, and the DNA content of nuclei were examined in metastatic brain tumors, which consisted of seven adenocarcinomas, a large cell carcinoma, a squamous cell carcinoma, a renal cell carcinoma and a mucoepidermoid carcinoma. A very high incidence of DNA changes was seen in these tumors. Proto-oncogene amplification and abnormal DNA content in the nuclear portion were found in 64% (7/11) and 67% (6/9) of cases, respectively. We also found double oncogene alteration in three cases metastasizing from lung, esophagus and kidney, and triple oncogene alteration in one case metastasizing from breast. We could not identify the common alterations in the group of metastatic brain tumor cells. These data suggest that the proto-oncogene amplifications and the alteration of DNA ploidy pattern may contribute to the metastatic process.

Regional differences in bromodeoxyuridine uptake, expression of Ki-67 protein, and nucleolar organizer region counts in glioblastoma multiforme

To investigate intratumoral differences in indices of tumor cell proliferation, we measured the bromodeoxyuridine labeling index (BrdUrd LI), the Ki-67 protein proliferating cell indices (PCIs) determined by monoclonal antibody MIB 1 in microwave-processed paraffin sections (MIB 1 PCI) and in some cases by monoclonal antibody in frozen sections (Ki-67 PCI), and counts of argyrophilic nucleolar organizer regions (AgNORs) in 20 glioblastomas. In the most actively proliferating areas, MIB 1 and Ki-67 PCIs correlated well with the BrdUrd LI and with each other, while AgNOR counts correlated less strongly with these indices. In less active areas, the MIB 1 PCI and BrdUrd LI changed concomitantly from one area to another within a tumor except in areas of pseudopalisading with necrosis; in these areas the BrdUrd LI decreased significantly compared with neighboring tumor tissue, while the MIB 1 PCI did not. There was very little staining of gemistocytic nuclei with either anti-BrdUrd or MIB 1 monoclonal antibodies; this supports the concept that gemistocytes are mainly quiescent cells. AgNORs in all of the above-mentioned areas varied from tumor to tumor, which suggests that they may indicate some cellular activity other than proliferation. The close correlation between the BrdUrd LI and Ki-67 protein PCIs in corresponding regions of glioblastomas suggests that MIB 1 staining of microwave-processed paraffin sections can be used to evaluate the growth potential of individual glioblastomas and possibly of other gliomas as well.

Cell kinetic analysis in pediatric brain and spinal tumors: a study of 117 cases with Ki-67 quantitation and flow cytometry

We present cell kinetic data including Ki-67 quantitation and flow cytometry on 117 pediatric brain/spinal cord tumors and review the literature. Although, in general, these proliferation indices are in agreement with the histologic grade, they are useful in prognostication in some instances when the histological features of malignancy are equivocal. Specific examples in which flow cytometry may prove particularly useful in this context are childhood ependymomas, which do not show frank anaplasia but have cellular foci with focal increase in mitoses, and choroid plexus neoplasms, where elevated S phase fractions have been associated with an adverse outcome. Thus Ki-67 quantitation and flow cytometry not only serve as useful adjuncts to conventional histologic grading but also in specific instances may provide new information on tumor prognosis.

p53 protein in low-grade astrocytomas: a study with long-term follow-up

The immunohistochemical expression of p53 protein (p53) was examined in 52 patients out of a series of 66 patients with low-grade astrocytomas with long-term follow-up. All patients were also evaluated for several clinical and histological features, among which only preoperative Karnofsky score and the extent of surgery were statistically significant parameters to predict outcome on multivariate analysis. p53 accumulation was seen in 46.1% of patients, with a wide range of percentage of positive cells. Median survival for p53-positive and p53-negative patients was 41 and 37 months respectively. The survival curves of p53-positive and -negative patients were not statistically different. However, the curves showed a trend towards a more aggressive course in p53-positive patients beginning 3-4 years after surgery. Five years after diagnosis the survival estimate with the Kaplan-Meier method was 21.2% for patients with p53-positive tumours and 45.9% for patients with p53-negative tumours. This trend is not due to different distribution of major clinical prognostic factors (age, incomplete resection or Karnofsky status). The trend could be related to the time needed by the p53-positive clone to outgrow the rest of the p53-negative neoplastic cell population. This hypothesis is further supported by the fact that the five recurrences which were surgically removed (one anaplastic astrocytoma and four glioblastomas) derived from p53-positive tumours and were themselves intensely p53 positive.

The application of 5-bromodeoxyuridine in the management of CNS tumors

A variety of clinical reports have described the application of the bromodeoxyuridine labeling index as an adjunct to conventional pathological examination of CNS tumors. This index has proven useful in predicting the clinical outcome associated with many such tumors. Furthermore, because of its efficacy as a radiosensitizing agent, bromodeoxyuridine (and the closely related iododeoxyuridine) has been used in combination with radiation therapy for malignant glial neoplasms, with some encouraging results. Although most studies suggest that bromodeoxyuridine is safe, there is evidence that this compound does have potential side-effects, including the observation that it is a mutagen and carcinogen in some experimental systems. A number of new alternative approaches for predicting the clinical outcome of CNS tumors has been developed based on an increased understanding of their molecular biology. However, until such approaches are better characterized, the clinical application of bromodeoxyuridine will continue to play an important role in predicting the clinical behavior of many CNS tumors.

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

We describe a technique for estimating the number of proliferating cells in gliomas and adjacent resection cavities after tumor removal. Proliferating cell nuclear antigen (PCNA) is a nuclear protein associated with the cell cycle. Anti-PCNA antibody staining provides a semiquantitative estimate of the number of proliferating cells found in fixed tissue embedded in paraffin. The extent of the staining of tumor cells of glioblastoma multiforme, anaplastic astrocytomas, low-grade gliomas, and other lesions of the brain with anti-PCNA antibody is correlated with the histological diagnosis. In addition, the labeling of the margins after resection of gliomas and other lesions with anti-PCNA antibody is also associated with the histological diagnosis of the lesion. This technique may be useful in estimating the "biological" extent of resection and in predicting the recurrence patterns of gliomas.

Hemangiopericytoma of the temporal bone presenting as a retroauricular mass

An unusual case of a hemangiopericytoma arising from the temporal bone is presented. The patient was noted to have a postauricular mass and was neurologically asymptomatic. A preoperative magnetic resonance image and an angiogram revealed the tumor to be highly vascular. Preoperative embolization facilitated the surgical removal of the tumor by rendering it avascular. Current therapy consists of radical resection of the tumor with postoperative radiation therapy. Patients must be monitored carefully for local recurrence and systemic metastasis.