Immunohistochemical markers for prognosis of cerebral glioblastomas

Progress in Glioma Stem Cell Research

Glioblastoma multiforme (GBM) represents a diverse spectrum of primary tumors notorious for their resistance to established therapeutic modalities. Despite aggressive interventions like surgery, radiation, and chemotherapy, these tumors, due to factors such as the blood-brain barrier, tumor heterogeneity, glioma stem cells (GSCs), drug efflux pumps, and DNA damage repair mechanisms, persist beyond complete isolation, resulting in dismal outcomes for glioma patients. Presently, the standard initial approach comprises surgical excision followed by concurrent chemotherapy, where temozolomide (TMZ) serves as the foremost option in managing GBM patients. Subsequent adjuvant chemotherapy follows this regimen. Emerging therapeutic approaches encompass immunotherapy, including checkpoint inhibitors, and targeted treatments, such as bevacizumab, aiming to exploit vulnerabilities within GBM cells. Nevertheless, there exists a pressing imperative to devise innovative strategies for both diagnosing and treating GBM. This review emphasizes the current knowledge of GSC biology, molecular mechanisms, and associations with various signals and/or pathways, such as the epidermal growth factor receptor, PI3K/AKT/mTOR, HGFR/c-MET, NF-κB, Wnt, Notch, and STAT3 pathways. Metabolic reprogramming in GSCs has also been reported with the prominent activation of the glycolytic pathway, comprising aldehyde dehydrogenase family genes. We also discuss potential therapeutic approaches to GSC targets and currently used inhibitors, as well as their mode of action on GSC targets.

Significant Systemic Insulin Resistance is Associated With Unique Glioblastoma Multiforme Phenotype

Background

Some glioblastoma multiforme (GBM) are characterized by the presence of gemistocytes (GCs), a unique phenotype of reactive astrocytes. Certain GCs can be identified as neoplastic cells but these cells were also found to be associated with diabetes in non-neoplastic lesions of the central nervous system. Our aim was to find a correlation between insulin - resistance metabolic features and the presence of GCs in patients with newly diagnosed GBM.

Methods

Medical records from histologically confirmed GBM patients were retrospectively extracted for different systemic metabolic variables. A statistic-based comparison was made between GBM, diabetic patients with and without GC. Patients with poorly controlled diabetes (ie, hemoglobin A1C ⩾ 8.0) were also compared between the 2 groups.

Results

A total of 220 newly diagnosed GBM patients were included in our study. 58 (26.3%) patients had a history of diabetes mellitus type 2 (DM2) at the time of admission. The rate of poorly-controlled DM2 was nearly as twice in the GC-GBM group than in the non-GC GBM group (18.75% vs 9.5%; P = .130). In the DM2 cohort, the subgroup of GC-GBM was significantly associated with demographic and metabolic features related to insulin resistance such as male gender predominance (89% vs 50%, P = .073) and morbid obesity (weight ⩾85 kg: OR 6.16; P = .0019 and mean BMI: 34.1 ± 11.42 vs 28.7 ± 5.44; P = .034 for group with and without GCs, respectively). In the poorly-controlled DM2 group, none of the GC-GBM patients were using insulin prior to diagnosis, compared to 61.1% in the non-GC GBM patients (OR = 0.04, P = .045).

Conclusion

Systemic metabolic factors related to marked insulin resistance (DM2, morbid obesity, male gender) are associated with a unique histologic phenotype of GBM, characterized by the presence of GCs. This feature is prominent in poorly-controlled DM2 GBM patients who are not using synthetic insulin. This novel finding may add to the growing data on the relevance of glucose metabolism in astrocytes and in astrocytes associated with high-grade gliomas. In GBM patients, a correlation between patients' metabolic status, tumor's histologic phenotype, tumor's molecular changes, use of anti-diabetic drugs and the respective impact of these factor on survival warrants further investigation.

Gemistocytes in newly diagnosed glioblastoma multiforme: Clinical significance and practical implications in the modern era

BACKGROUND

Gemistocytes (GCs) in low grade gliomas are associated with rapid growth and worse prognosis. However, their clinical significance in glioblastomas (GBM) is a matter of debate.

AIM OF STUDY

To investigate the clinical significance of the presence of GCs in newly-diagnosed GBM patients in the modern era.

METHODS

Computerized medical records from newly diagnosed GBM patients were retrospectively reviewed and extracted for demographic, clinical, radiological and pathological variables. Patients with at least 5% GCs of neoplastic cells were considered GC-GBM (group 1). All other cases were considered non-GC GBM (group 2). Group 1 was further divided into two subgroups: Low percentage GCs (group 1a, ≤ 20% GCs) and high percentage GC (group 1b, >20% GCs).

RESULTS

A total of 220 patients with newly diagnosed GBM were included. 14.5% were defined as GC-GBM (group I, n = 32) and 85.5% were defined as non-GC GBM (group 2, n = 188). 8.5% had ≤ 20% GCs (group 1a, n = 19) and 5.9% had > 20% GCs (group 1b, n = 13). Groups were similar for most epidemiological and clinical variables. There was a trend toward worse prognosis in group 1b. Several distinguished radiological and molecular features were observed in group 1.

CONCLUSION

GCs are found in minority of naïve, newly diagnosed, GBM cases in adults. They seem to carry minimal implications on daily clinical practice. Higher percentage of GCs is associated with distinct radiological features such as multifocality that might be correlated with decreased OS. High-percentage GC-GBMs are also associated with increased prevalence of isocitrate dehydrogenase (IDH) mutations.

Clinicopathological characteristics and treatment outcomes of epithelioid glioblastoma

Epithelioid glioblastoma is a new variant of glioblastoma that has been recently recognized in the 2016 WHO classification of brain tumors. Given the rarity of epithelioid glioblastoma, the clinical characteristics, pathological features, radiological findings, and treatment outcomes are still not well characterized. Therefore, we identified eighty-four epithelioid glioblastoma cases to investigate these characteristics and identify the possible prognostic factors of survival. There were 55 male and 29 female patients with a mean age of 33.6 years. Headache (77.3%) was the most common clinical symptom, and other common symptoms included nausea or vomiting (34%), dizziness (20.5%), seizures (13.6%), and limb weakness (13.6%). Most lesions (88.1%) were located in cerebral lobes, especially in the frontal lobe and temporal lobe. One hundred percent of the patients were IDH1 wild-type (75/75) and INI-1 positive (58/58), and 57.3% (47/82) of patients harbored BRAF^V600E mutation. The median overall survival (OS) of all patients was 10.5 months. Patients who received chemotherapy (p = 0.006) or radiotherapy (p = 0.022) had a longer survival than patients who did not. In addition, the K-M curve showed that the BRAF^V600E mutation status was not associated with survival (p = 0.724). These findings may assist clinicians with better understanding and management of epithelioid glioblastoma.

EGFR as a clinical marker in glioblastomas and other gliomas

Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein and a member of the tyrosine kinase superfamily receptor. Gliomas are tumors originating from glial cells, which show a range of aggressiveness depending on grade and stage. Many EGFR gene alterations have been identified in gliomas, especially glioblastomas, including amplifications, deletions and single nucleotide polymorphisms (SNPs). Glioblastomas are discussed as a separate entity due to their high correlation with EGFR mutants and the reported association of the latter with survival and response to treatment in this glioma subgroup. This review is a comprehensive report of EGFR gene alterations and their relations with several clinical factors in glioblastomas and other gliomas. It covers all EGFR gene alterations including point mutations, SNPs, methylations, copy number variations and amplifications, assessed with regard to different clinical variables, including response to therapy and survival. This review also discusses the current prognostic status of EGFR in glioblastomas and other gliomas, and highlights gaps in previous studies. This serves as an update for the medical community about the role of EGFR gene alterations in gliomas and specifically glioblastomas, as a means for targeted treatment and prognosis.

Prognostic significance of epidermal growth factor receptor expression in glioma patients

Purpose

There is a great controversy regarding the prognostic significance of epidermal growth factor receptor (EGFR) in glioma patients. The current meta-analysis was conducted to evaluate the effect of abnormal EGFR expression on overall survival in glioma patients.

Materials and methods

A comprehensive literature search of PubMed, EMBASE, Google Scholar, Web of Science, and Cochrane Library was conducted. The combined hazard ratio (HR) and its 95% confidence intervals (CIs) were used to evaluate the association between EGFR expression and survival in glioma.

Results

A total of 476 articles were screened, and 17 articles containing 1,458 patients were selected. The quality assessment of the included studies was performed by the Newcastle-Ottawa Scale. Overexpression of EGFR was found to be an indicator of poor prognosis in overall survival in glioma patients (HR =1.72, 95% CI 1.32-2.25, P=0.000, random effect) and glioblastoma multiforme patients (HR =1.57, 95% CI 1.15-2.14, P=0.004, random effect). Subgroup analysis was conducted to explore the source of high heterogeneity.

Conclusion

This meta-analysis indicated that high expression of EGFR may serve as a biomarker for poor prognosis in glioma patients.

Critical review about MDM2 in cancer: Possible role in malignant mesothelioma and implications for treatment

The tumor suppressor p53 regulates genes involved in DNA repair, metabolism, cell cycle arrest, apoptosis and senescence. p53 is mutated in about 50% of the human cancers, while in tumors with wild-type p53 gene, the protein function may be lost because of overexpression of Murine Double Minute 2 (MDM2). MDM2 targets p53 for ubiquitylation and proteasomal degradation. p53 reactivation through MDM2 inhibitors seems to be a promising strategy to sensitize p53 wild-type cancer cells to apoptosis. Moreover, additional p53-independent molecular functions of MDM2, such as neoangiogenesis promotion, have been suggested. Thus, MDM2 might be a target for anticancer treatment because of its antiapoptotic and proangiogenetic role. Malignant pleural mesothelioma (MPM) is an aggressive asbestos-related tumor where wild-type p53 might be present. The present review gives a complete landscape about the role of MDM2 in cancer pathogenesis, prognosis and treatment, with particular focus on Malignant Pleural Mesothelioma.

The effect of silver nanoparticles (AgNPs) on proliferation and apoptosis of in ovo cultured glioblastoma multiforme (GBM) cells

Recently, it has been shown that silver nanoparticles (AgNPs) provide a unique approach to the treatment of tumors, especially those of neuroepithelial origin. Thus, the aim of this study was to evaluate the impact of AgNPs on proliferation and activation of the intrinsic apoptotic pathway of glioblastoma multiforme (GBM) cells cultured in an in ovo model. Human GBM cells, line U-87, were placed on chicken embryo chorioallantoic membrane. After 8 days, the tumors were divided into three groups: control (non-treated), treated with colloidal AgNPs (40 μg/ml), and placebo (tumors supplemented with vehicle only). At the end of the experiment, all tumors were isolated. Assessment of cell proliferation and cell apoptosis was estimated by histological, immunohistochemical, and Western blot analyses. The results show that AgNPs can influence GBM growth. AgNPs inhibit proliferation of GBM cells and seem to have proapoptotic properties. Although there were statistically significant differences between control and AgNP groups in the AI and the levels of active caspase 9 and active caspase 3, the level of these proteins in GBM cells treated with AgNPs seems to be on the border between the spontaneous apoptosis and the induced. Our results indicate that the antiproliferative properties of silver nanoparticles overwhelm proapoptotic ones. Further research focused on the cytotoxic effect of AgNPs on tumor and normal cells should be conducted.

Management and survival rates in patients with glioma in China (2004-2010): a retrospective study from a single-institution

To analyze the clinical characteristics and prognostic factors in patients with glioma in an academic institute in China. From October 2004 to August 2010, total 1,285 patients were diagnosed as glioma at the Glioma Center of Beijing Tiantan Hospital. Clinical and molecular pathology features and survival rates were analyzed. The median overall survival (OS) times were 78.1, 37.6 and 14.4 months for low-grade glioma (WHO grade II), anaplastic glioma (WHO grade III) and glioblastoma (WHO grade IV), respectively. In patients with low-grade glioma, age, preoperative Karnofsky performance scale (KPS), pathological type, radiotherapy, O(6)-methylguanine-DNA methyltransferase (MGMT) expression and Ki-67 expression, were significantly associated with OS in multivariate analyses; and preoperative KPS and radiotherapy were significantly associated with progression-free survival (PFS). For anaplastic gliomas, age, preoperative KPS, pathological type, extent of resection, radiotherapy, p53 expression and phosphatase and tensin homolog (PTEN) expression were associated with OS. For glioblastomas, age, preoperative KPS, pathology type, extent of resection, radiotherapy and chemotherapy were associated with OS; and age, gender, preoperative KPS, extent of resection, radiotherapy and chemotherapy were associated with PFS. This is the largest survey for glioma management in China to date. We found significant differences in age, presenting symptoms and the expression of p53, MGMT, PTEN, and Ki-67 among patients with different types of glioma. Age, preoperative KPS, tumor grades, radiotherapy, chemotherapy and Ki-67 expression were significantly associated with clinical prognosis.

Seizure characteristics and outcomes in 508 Chinese adult patients undergoing primary resection of low-grade gliomas: a clinicopathological study

Seizure is a common presenting manifestation and plays an important role in the clinical presentation and quality of life for patients with low-grade gliomas (LGGs). The authors set out to identify factors that influence preoperative seizure characteristics and postoperative seizure control. Cases involving adult patients who had undergone initial surgery for LGGs in a single institution between 2005 and 2009 were retrospectively reviewed. Univariate and multivariate logistic regression analyses were used to identify factors associated with preoperative seizures and postoperative seizure control. Of the 508 patients in the series, 350 (68.9%) presented with seizures. Age less than 38 years and cortical involvement of tumor were more likely to be associated with seizures (P = .003 and .001, respectively, multivariate logistic analysis). For the cohort of 350 patients with seizures, Engel classification was used to evaluate 6- and 12-month outcome after surgery: completely seizure free (Engel class I), 65.3% and 62.5%; not seizure free (Engel classes II, III, IV), 34.7% and 37.5%. After multivariate logistic analysis, favorable seizure prognosis was more common in patients with secondary generalized seizure (P = .006) and with calcification on MRI (.031). With respect to treatment-related variables, patients achieved much better seizure control after gross total resection than after subtotal resection (P < .0001). Ki67 was an independent molecular marker predicting poor seizure control in the patients with a history of seizure if overexpressed but was not a predictor for those without preoperative seizures. These factors may provide insight into developing effective treatment strategies aimed at prolonging patients' survival.

Prognostic factors for long-term survival after glioblastoma

Long-term survivors of glioblastoma (GB) are rare. Several variables besides tumor size and location determine a patient's survival chances: age at diagnosis, where younger patients often receive more aggressive treatment that is multimodal; functional status, which has a significant negative correlation with age; and histologic and genetic markers.

Epidermal growth factor receptor in glioma: signal transduction, neuropathology, imaging, and radioresistance

Aberrant epidermal growth factor receptor (EGFR) signaling is common in cancer. Increased expression of wild type and mutant EGFR is a widespread feature of diverse types of cancer. EGFR signaling in cancer has been the focus of intense investigation for decades primarily for two reasons. First, aberrant EGFR signaling is likely to play an important role in the pathogenesis of cancer, and therefore, the mechanisms of EGFR-mediated oncogenic signaling are of interest. Second, the EGFR signaling system is an attractive target for therapeutic intervention. EGFR gene amplification and overexpression are a particularly striking feature of glioblastoma (GBM), observed in approximately 40% of tumors. GBM is the most common primary malignant tumor of the central nervous system in adults. In approximately 50% of tumors with EGFR amplification, a specific EGFR mutant (EGFRvIII, also known as EGFR type III, de2-7, Delta EGFR) can be detected. This mutant is highly oncogenic and is generated from a deletion of exons 2 to 7 of the EGFR gene, which results in an in-frame deletion of 267 amino acids from the extracellular domain of the receptor. EGFRvIII is unable to bind ligand, and it signals constitutively. Although EGFRvIII has the same signaling domain as the wild type receptor, it seems to generate a distinct set of downstream signals that may contribute to an increased tumorigenicity. In this review, we discuss recent progress in key aspects of EGFR signaling in GBM, focusing on neuropathology, signal transduction, imaging of the EGFR, and the role of the EGFR in mediating resistance to radiation therapy in GBM.

Glioma diagnosis: immunohistochemistry and beyond

Clinicians and pathologists have been inundated by published reports of new and potentially interesting diagnostic, prognostic, and putative predictive "markers" whose expression (or loss) holds great promise for more enlightened diagnoses and ultimately better patient care. Although an understanding of therapeutically (and possibly diagnostically) relevant pathways of glioblastoma may be at hand, significant challenges remain. Many immunohistochemical and genetic tests have proven to be useful in the stratification of clinical trials, whereas the utility of many others for the day-to-day practice of pathology awaits further study and validation. The importance of critical literature review and careful consideration of practical issues such as test standardization, compliance, cost-effectiveness, and availability must all be considered before implementing any new diagnostic test. This review will focus on the role of immunohistochemistry in the routine diagnosis of astrocytic and oligodendrocytic tumors and in assisting with the diagnosis of some less common gliomas that have ependymal-like features. It will conclude with a summary of molecular and genetic studies, which not only hold great promise for improved diagnosis, but also reveal prognostic information on disease outcome and predict response to treatment or provide biologic targets for novel therapies.

Immunoexpression of tumor suppressor genes p53, p21 WAF1/CIP1 and p27 KIP1 in humam astrocystic tumors

The aim of the present study was to evaluate the tumor suppressor genes p53, p21 WAF1/CIP1 and p27 KIP1 expression in astrocytic tumors, correlating the findings with the histopathological grade (WHO). An immunohistochemical study of the p53, p21 and p27 proteins using the streptavidin-biotin-peroxidase method was performed in fifty-five astrocytomas (13 grade I, 14 grade II, 7 grade III and 21 grade IV) and five samples of non-tumor brain tissue (negative control). p53 positive indices (PI) and labeling indices (LI) showed tendency to increase according to malignant progression. The nuclear expression of p27 presented similar inclination, except for the PI reduction verified in grade IV tumors. Otherwise, the cytoplasmic p27 staining was more evident between high-grade tumors (III and IV). p53 and nuclear p27 expression was correlated with the histological classification (p<0.01; test H). On the other hand, p21 indices revealed a propensity to reduction in agreement with malignant evolution of the astrocytic tumors, except for high scores observed in grade IV tumors. The non-tumor samples did not show any expression of these proteins. These results indicated the p53 mutation as an initial, relevant and potentially predictor of tumor progression event in astrocytomas, with the detection of p21 protein as an important resource for the deduction of functional situation of this gene. Moreover, the activation of p27 KIP1 was preserved in the astrocytic tumors and its cytoplasmic manifestation seems to be resultant of its nuclear expression, not demonstrating a direct impact in astrocytomas tumorigenesis.

The role of osteopontin in tumor progression and metastasis in breast cancer

The use of cancer biomarkers to anticipate the outlines of disease has been an emerging issue, especially as cancer treatment has made such positive steps in the last few years. Progress in the development of consistent malignancy markers is imminent because advances in genomics and bioinformatics have allowed the examination of immense amounts of data. Osteopontin is a phosphorylated glycoprotein secreted by activated macrophages, leukocytes, and activated T lymphocytes, and is present in extracellular fluids, at sites of inflammation, and in the extracellular matrix of mineralized tissues. Several physiologic roles have been attributed to osteopontin, i.e., in inflammation and immune function, in mineralized tissues, in vascular tissue, and in kidney. Osteopontin interacts with a variety of cell surface receptors, including several integrins and CD44. Binding of osteopontin to these cell surface receptors stimulates cell adhesion, migration, and specific signaling functions. Overexpression of osteopontin has been found in a variety of cancers, including breast cancer, lung cancer, colorectal cancer, stomach cancer, ovarian cancer, and melanoma. Moreover, osteopontin is present in elevated levels in the blood and plasma of some patients with metastatic cancers. Therefore, suppression of the action of osteopontin may confer significant therapeutic activity, and several strategies for bringing about this suppression have been identified. This review looks at the recent advances in understanding the possible mechanisms by which osteopontin may contribute functionally to malignancy, particularly in breast cancer. Furthermore, the measurement of osteopontin in the blood or tumors of patients with cancer, as a way of providing valuable prognostic information, will be discussed based on emerging clinical data.

Role of MIB1 in predicting survival in patients with glioblastomas

BACKGROUND

Histologic immunomarkers of cell cycle proteins have been utilized for prognosis in high-grade astrocytic tumors. One such marker, MIB1, an antibody immunoreactive throughout the cell cycle, is predictive of more aggressive disease and poorer prognosis in astrocytomas. An independent role of MIB1 analysis for survival prediction and clinical management within histologic grades has not been clearly proven.

METHODS

This study retrospectively evaluated MIB1 reactivity in tissue samples from 116 patients with glioblastomas on initial medical presentation. Clinical variables considered included gender, age, Karnofsky Performance Scores (KPS), extent of surgical resection, adjuvant radiation and survival.

RESULTS

Univariate and multivariate analyses were used to correlate these variables with MIB1 staining. MIB1 staining does not predict overall survival or response to adjuvant therapy as an independent risk factor.

CONCLUSION

MIB1 labeling does not predict patient survival as an independent variable and does not predict response to additional therapies. Patient survival with glioblastoma was predicted by KPS, age, extent of resection and use of adjuvant radiotherapy.

In vivo research in astrocytoma cell proliferation with 1H-magnetic resonance spectroscopy: correlation with histopathology and immunohistochemistry

INTRODUCTION

Assessment of brain tumor proliferative potential provides important prognostic information that supplements standard histopathologic grading. Proton magnetic resonance spectroscopy ((1)H-MRS) gives completely different information, relating to cell membrane proliferation, neuronal damage, energy metabolism and necrotic transformation of brain or tumor tissues. The aim of this study was to investigate the relationship between (1)H-MRS and tumor proliferative potential in astrocytomas.

METHODS

We studied 34 patients with histologically verified astrocytomas using the (1)H-MRS protocol following routine MRI preoperatively. The tumor in 26 of these patients was classified as grade I/II (low grade), and the tumor in the remaining patients as grade III/IV (high grade) according to the World Health Organization classification criteria of nervous system tumors (2000). The tumor in 21 patients was homogeneous astrocytoma, and of these 17 were classified as low grade and 4 as high grade. Expression of proliferating cell nuclear antigen (PCNA) was determined immunohistochemically using streptavidin-biotin-peroxidase complex (SP) staining.

RESULTS

The ratios of choline (Cho) to N-acetylaspartate (NAA) and Cho to creatine (Cr) in those with high-grade astrocytomas (n=4) were significantly higher than in those with low-grade astrocytomas (n=17) (t=2.899, P=0.009; t=3.96, P=0.001, respectively), and were found to be significantly correlated with the expression of PCNA in 21 patients with homogeneous astrocytomas (r=0.455, P=0.038; r=0.633, P=0.002, respectively).

CONCLUSIONS

We conclude that (1)H-MRS may be a valuable method for predicting preoperatively the degree of malignancy of homogeneous astrocytomas by enabling the calculation of the Cho/NAA and Cho/Cr ratios in vivo, and indirect evaluation of the tumor proliferative potential and prognosis, which are not available using conventional magnetic resonance imaging (MRI).

Expression of Drug Resistance Proteins Pgp, MRP1, MRP3, MRP5 AND GST-π in Human Glioma

Chemotherapy in glioma is poorly effective: the blood-brain barrier and intrinsic and/or acquired drug resistance of tumor cells could partly explain this lack of major effect. We investigated expression of P-glycoprotein (Pgp), multidrug resistance protein (MRP) 1, MRP3, MRP5 and glutathione-S-transferase pi (GST-pi) in malignant glioma patients. Cytofluorimetric analysis of 48 glioma specimens and 21 primary cultures showed high levels of MRP1, moderate levels of MRP5 and low levels of Pgp, GST-pi and MRP3. Immunohistochemistry (25 glioma specimens) showed expression of GST-pi (66.7% of cases), MRP1 (51.3%), MRP5 (45.8%), Pgp (34.8%) and MRP3 (29.9%) in tumor cells. Moreover, analysis of tumor samples by real time quantitative PCR showed mRNA expression of all investigated genes. Tumor vasculature, analyzed in glioma specimens and in tumor derived endothelial cells, showed expression of all investigated proteins. Non-tumor brain samples (from a patient with arteriovenous malformation and from one with epilepsy), normal human astrocytes and cultured endothelial cells were also analyzed: astrocytes and endothelial cells expressed the highest levels of the investigated proteins, mainly MRP1 and MRP5. No significant differences in proteins expression were detected between primary or recurrent gliomas, suggesting that glioma chemoresistance is mostly intrinsic. Therefore, we detected, for the first time, the presence of MRP3 and MRP5 on glioma specimens--both in tumor and endothelial cells--and we delineated an expression profile of chemoresistance proteins in glioma. The possible association of inhibitors of drug efflux pumps with chemotherapy could be investigated to improve drugs delivery into the tumor and their cytotoxic effects.

Molecular diagnostics in central nervous system tumors

Central nervous system (CNS) neoplasms can be diagnostically challenging, due to remarkably wide ranges in histologic appearance, biologic behavior, and therapeutic approach. Nevertheless, accurate diagnosis is the critical first step in providing optimal patient care. As with other oncology-based specialties, there is a rapidly expanding interest and enthusiasm for identifying and utilizing new biomarkers to enhance the day-to-day practice of surgical neuropathology. In this regard, the field is primed by recent advances in basic research, elucidating the molecular mechanisms of tumorigenesis and progression in the most common adult and pediatric brain tumors. Thus far, few have made the transition into routine clinical practice, the most notable example being 1p and 19q testing in oligodendroglial tumors. However, the field is rapidly evolving and many other biomarkers are likely to emerge as useful ancillary diagnostic, prognostic, or therapeutic aids. The goal of this article is to highlight the most common genetic alterations currently implicated in CNS tumors, focusing most on those that are either already in common use in ancillary molecular diagnostics testing or are likely to become so in the near future.

Prognostic value of Mdm2, p53 and p16 in patients with astrocytomas

Surgical cure of gliomas infiltrating into the brain is practically impossible and their clinical course is primarily determined by the biological behavior of the tumor cell. The purpose of this study was to analyze retrospectively prognostic input of p53, Mouse double minute-2 (Mdm2) and p16 in 103 uniformly treated patients with astrocytic tumors. The expression of these molecules was measured by immunohistochemical procedure. Prognostic evaluation was performed with the multivariate proportional hazards model. The follow-up period lasted 19 (5-122) months for the survivors. We observed that 66% of gliomas showed mutated p53, while only 17% overexpressed Mdm2, the p53-regulatory molecule. Besides, almost 50% of gliomas lost p16 immunopositivity. Only p53 labeling showed a positive correlation with the grade of malignancy, according with the WHO classification. The association between mutated p53 and histological grade remained when prognostic variables were considered in a multivariate analysis. No association between p53 status and overall survival was found. On the other hand, Mdm2 overexpression and, unexpectedly, p16 immunopositivity were associated with a shorter survival in an univariate analysis. However, Cox-regression analysis showed that only Mdm2 in female patients was an independent prognostic factor, associated with shorter survival. In conclusion, our results suggest that Mdm2 could be a relevant marker in determining the evolution of glioma patients and could provide a more objective way to classify astrocytomas.

EGF-R and PDGF-R, but not bcl-2, overexpression predict overall survival in patients with low-grade astrocytomas

BACKGROUND AND OBJECTIVES

Therapy of malignant glioma tumors is based on histology and clinical factors. However, comparable lesions may correspond with important prognostic differences. Our purpose was to analyze retrospectively the prognostic input of platelet-derived growth factor receptor (PDGF-R), epidermal growth factor (EGF-R), and bcl-2 expression in 103 malignant gliomas from uniformly treated patients.

METHODS

The expression of the antigens was analyzed by immunohistochemistry (IHC). Prognostic evaluation was performed with the multivariate proportional hazards model. The follow-up period lasted 19 (5-122) months for survivors.

RESULTS

We observed that almost 50% of gliomas showed high expression of PDGF-R, while a lower expression of EGF-R and bcl-2 was found. No association between the main prognostic factors in malignant glioma (sex, age, histological grade, and Karnofsky score) and the labeling index (LI) of these antigens was observed. We found that only PDGF-R and EGF-R overexpression were associated with a shorter survival in patients with World Health Organization (WHO) II astrocytomas, being both associations independent of known prognostic factors, as shown by Cox model. Besides, we confirmed other authors' results that high histological grade and low performance score were associated with worse prognosis.

CONCLUSIONS

PDGF-R and EGF-R expression could be relevant in determining the prognosis of low-grade astrocytomas (LGAs) and in providing a more objective mechanism for their classification.

MDM2 and Prognosis

The cellular stress response pathway regulated by the p53 tumor suppressor is critical to the maintenance of genomic integrity and to the prevention of oncogenic transformation. Intracellular levels of p53 are tightly regulated by an autoregulatory feedback loop comprised of p53 and MDM2. It might be predicted that disruption of this loop, either through p53 mutation or overexpression of MDM2, would be a negative prognostic marker for cancer development, likelihood of relapse, or response to therapy. In fact, although MDM2 overexpression is common in cancer, it can be both a positive and a negative predictor of outcome in different tumors, and its significance as a biomarker remains controversial. Data from a number of different tumor types are reviewed for the predictive significance of MDM2 expression, along with evidence for different mechanisms of MDM2 overexpression in these different tumors.

In light of the biological complexities underlying the p53-MDM2 loop, it is, perhaps, not surprising that no simple paradigm exists that is generally applicable. Much work remains to be done to elucidate the basic mechanisms underlying the physical interactions between the two proteins, the role of protein modifications in altering those interactions, and also the genetic and transcriptional deregulations by which protein levels are altered in human cancers. Only in this way will truly biologically relevant predictive factors emerge.

Microwave cell death: Enzyme histochemical evaluation for metastatic carcinoma of the liver

We have reported that microwave cell death is a unique cell death preserving not only cell and nuclear shapes but also immunohistochemical antigenicity. However, their enzyme activity was lost, which indicated cell dysfunction and death. This peculiar observation implies that the microwave effect is likely an 'in situ' tissue fixation and that this type of cell death is morphologically different from cell death, by either oncosis or apoptosis, as previously known. To confirm whether this peculiar cell death was observed also in human tissue samples, we examined clinical samples from patients with metastatic liver cancer, which were treated with microwave irradiation. They were examined immunohistochemically for human Ki-67 antigen and proliferating cell nuclear antigen and enzyme histochemically for alkaline phosphatase, and the same morphological changes that were observed in microwave-treated rat liver were found. In conclusion, we believe that routine hematoxylin-eosin stain alone is not a suitable method to evaluate microwave treatment for cancer because microwave coagulation therapy-treated cells preserved their nuclei and cellular architectures, even after 3 months. For microwave-treated tumors, enzyme histochemistry is helpful to determine its effectiveness.