Angiogenesis in patients with craniopharyngiomas: correlation with treatment and outcome

First evidence of anti-VEGF efficacy in an adult case of adamantinomatous craniopharyngioma: Case report and illustrative review

BACKGROUND

Craniopharyngioma (CP) is a neurosurgical challenge, due to location and to the substantial risk of morbidity associated with surgical resection. Recent advances in molecular research have identified a mutation signature in papillary craniopharyngiomas: BRAF V600E. This has led to targeted therapy, yielding positive results. Despite numerous studies of the pathophysiology of adamantinomatous craniopharyngioma, treatment options for molecular-based therapy are still lacking. The objective of our study was to provide an illustrative review of the literature on possible molecular targets in adamantinomatous craniopharyngioma and to report the case of a patient harboring an adamantinomatous craniopharyngioma deemed unsuitable for surgical resection, in which an anti-VEGF antibody was used to achieve tumor control.

CASE REPORT

An 84-year-old-man was referred to our department with a history of visual loss caused by recurrent infundibular adamantinomatous craniopharyngioma. A first surgical attempt to reduce the cystic portion of the tumor compressing the optic pathway failed. Due to rapid worsening of visual function, adjuvant therapy with bevacizumab was initiated before radiotherapy.

RESULTS

Neuroradiological and ophthalmological follow-up showed a decrease in tumor volume and improvement in visual function as early as 6 weeks after commencing therapy. These results were confirmed 3 months after commencement of chemotherapy. Radiotherapy was scheduled for long-term tumor control.

CONCLUSIONS

To the best of our knowledge, our case is the first in the literature in which targeted therapy using anti-VEGF was successfully used as a single agent to treat adamantinomatous craniopharyngioma, with favorable outcome in terms of tumor shrinkage and clinical improvement. These preliminary results may open new perspectives for the management of adamantinomatous craniopharyngioma. Validation of this approach requires additional clinical evidence.

Predictive Factors for Pediatric Craniopharyngioma Recurrence: An Extensive Narrative Review

Despite being classified as benign tumors, craniopharyngiomas (CPs) are associated with significant morbidity and mortality due to their location, growth pattern, and tendency to recur. Two types can be identified depending on age distribution, morphology, and growth pattern, adamantinomatous and papillary. The adamantinomatous CP is one of the most frequently encountered central nervous system tumors in childhood. Our aim was to review the relevant literature to identify clinical, morphological, and immunohistochemical prognostic factors that have been implicated in childhood-onset CP recurrence. Lack of radical surgical removal of the primary tumor by an experienced neurosurgical team and radiotherapy after a subtotal excision has been proven to significantly increase the recurrence rate of CP. Other risk factors that have been consistently recognized in the literature include younger age at diagnosis (especially <5 years), larger tumor size at presentation, cystic appearance, difficult tumor location, and tight adherence to surrounding structures, as well as the histological presence of whorl-like arrays. In addition, several other risk factors have been studied, albeit with conflicting results, especially in the pediatric population. Identifying risk factors for CP recurrence is of utmost importance for the successful management of these patients in order to ultimately ensure the best prognosis.

The molecular pathogenesis of craniopharyngiomas

Research from the last 20 years has provided important insights into the molecular pathogenesis of craniopharyngiomas (CPs). Besides the well-known clinical and histological differences between the subtypes of CPs, adamantinomatous (ACP) and papillary (PCP) craniopharyngiomas, other molecular differences have been identified, further elucidating pathways related to the origin and development of such tumors. The present minireview assesses current knowledge on embryogenesis and the genetic, epigenetic, transcriptomic, and signaling pathways involved in the ACP and PCP subtypes, revealing the similarities and differences in their profiles. ACP and PCP subtypes can be identified by the presence of mutations in CTNNB1 and BRAF genes, with prevalence around 60% and 90%, respectively. Therefore, β-catenin accumulates in the nucleus-cytoplasm of cell clusters in ACPs and, in PCPs, cell immunostaining with specific antibody against the V600E-mutated protein can be seen. Distinct patterns of DNA methylation further differentiate ACPs and PCPs. In addition, research on genetic and epigenetic changes and tumor microenvironment specificities have further clarified the development and progression of the disease. No relevant transcriptional differences in ACPs have emerged between children and adults. In conclusion, ACPs and PCPs present diverse genetic signatures and each subtype is associated with specific signaling pathways. A better understanding of the pathways related to the growth of such tumors is paramount for the development of novel targeted therapeutic agents.

Targeted therapies in the medical management of craniopharyngioma

Craniopharyngioma (CP) is an intracranial benign tumor that behaves aggressively due to its location, infiltration of the surrounding nervous tissue and high capacity for recurrence. Treatment of choice is surgery followed or not by radiotherapy. Recent advances in molecular biology techniques and the better understanding of the genetic alterations of the two histological types of CP have open new therapeutic perspectives with targeted drugs. Adamantinomatous CP (ACP) is associated with activating mutations of the CTNNB1 gene. Such mutations are accompanied by intracellular accumulation of β-catenin, an oncogenic protein that activates the intracellular Wnt/ β-catenin signaling pathway, which regulates the transcription of genes involved in cell proliferation. Therefore, the use of molecular therapies directed against the activation of the Wnt/ β-catenin pathway could be an attractive and promising therapeutic option in the management of ACPs. On the other hand, papillary CP (PCP) is associated with activating mutations in the BRAF gene. This gene encodes a BRAF protein that plays an important role in the intracellular mitogen-activated protein kinase (MAPK) signaling pathway, which also regulates cell proliferation. The use of BRAF inhibitors either in monotherapy or in combination with mitogen-activated protein kinase (MEK) inhibitors has demonstrated therapeutic efficacy in isolated clinical cases of relapsed PCPs. A preliminary report of a recent phase II clinical trial has shown a therapeutic response in 93.7% of patients with BRAF ^V600E -mutated PCP, with an 85% reduction in tumor size. In the present review we comment on the efficacy and safety of the different drugs being used in patients with PCP.

Ki67 as a prognostic factor of craniopharyngioma's recurrence in paediatric population

PURPOSE

Craniopharyngioma is one of the most frequent benign tumours of the central nervous system in the paediatric population. Although it is a benign tumour according to the WHO classification, it significantly deteriorates the patient's quality of life. The aim of this study is to assess if proliferation index Ki67 can be a useful marker of the risk of craniopharyngioma's recurrence.

METHODS

Expression of Ki67 was examined in 85 specimens of primary craniopharyngioma and in 11 specimens of the recurring tumour. In all the cases, adamantinomatous type of craniopharyngioma was diagnosed. Values of Ki67 expression were compared between patients with and without recurrence, between patients with progression and relapse and between primary and recurrent tumours.

RESULTS

No statistically significant differences were found between proliferation index Ki67 values in tumours with recurrence and without (median values 2.5% and 3%, respectively, p = 0.69). The median value of proliferation index Ki67 in progression group was 1% and in the relapse group 4%; no statistical significance between those groups was found (p = 0.067). The median value of proliferation index Ki67 in primary tumours was 3% (0-20%) and in recurrent tumours it was 5% (0-14%). Despite the lack of statistical significance (p = 0.61), a tendency towards higher values of Ki67 in recurring tumours in comparison with primary tumours was shown.

CONCLUSIONS

Proliferation index Ki67 is not a reliable prognostic factor of craniopharyngioma's recurrence.

Impact of neutrophil-lymphocyte ratio on long-term outcome in patients with craniopharyngioma

Neutrophil-lymphocyte ratio (NLR) is a poor prognostic factor in many tumors including glioblastoma multiforme (GBM), colorectal, and prostate cancer. The aim of this study was to investigate the prognostic value of preoperative NLR in patients with craniopharyngioma.Around 149 patients of craniopharyngioma surgically were treated at the Department of Neurosurgery, West China Hospital from January 2008 to December 2010, including 84 males and 65 females aged from 6 to 70 years were retrospectively reviewed, and preoperative NLR was analyzed. Overall survival (OS), progression free survival (PFS), and quality of life (QOL) were evaluated.The 5-year OS and PFS rates were 81.21% and 75.84%. Preoperative NLR was significantly correlated with OS (HR = 1.44, 95% CI 1.16-1.79, P = .001) and PFS (HR = 1.46, 95% CI 1.22-1.74, P < .001). The best cut-off value of NLR was found to be 4 based on the receiver operator characteristics (ROC) curve. Patients with NLR ≥4 had a significantly worse QOL (P = .039), lower OS rate (P = .009), and PFS rate (P < .001).Preoperative NLR may be a simple, readily available, and valid predictor of long-term outcome in craniopharyngioma. We suggest that the NLR can provide effective guidance to neurosurgeons for more information about the tumor and prognostic evaluation.

Phosphorus-32 interstitial radiotherapy for recurrent craniopharyngioma: Expressions of vascular endothelial growth factor and its receptor-2 and imaging features of tumors are associated with tumor radiosensitivity

To investigate the relationship of the expression of vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor-2 (VEGFR-2) and imaging features with the therapeutic efficacy of Phosphorus-32 colloid interstitial radiotherapy in recurrent craniopharyngioma.Thirty-two patients with recurrent craniopharyngioma underwent phosphorus-32 colloid interstitial radiotherapy. The tumor imaging features were classified into 4 types according to the thickness of the cyst wall and signals of the cyst contents as shown by computed tomography (CT) and magnetic resonance imaging (MRI) images. Protein expressions of VEGF and VEGFR-2 in craniopharyngioma tissues were evaluated with immunohistochemistry before radiotherapy. The tumor radiosensitivity was determined at 12 months after the interstitial radiotherapy.VEGF mainly expressed in the tumor cytoplasm, and VEGFR-2 expressed either in vascular endothelial cells or in tumor endothelial cells. VEGF/VEGFR-2 expressions varied significantly in cases sensitive or insensitive to the radiotherapy (VEGF: P = .028; VEGFR-2: P = .017). Tumor imaging features were associated with the therapeutic efficacy of interstitial radiotherapy (P = .000). VEGF expression had no association with the imaging features of tumors (P = .226), but VEGFR-2 expression was associated with the imaging features of tumors (P = .008).Our results confirmed the association among imaging features, VEGFR-2 expressions, and tumor radiosensitivity in craniopharyngiomas. Imaging features and VEGFR-2 expressions may add useful data to the radiosensitive assessment of craniopharyngiomas.

ELTD1, an effective anti-angiogenic target for gliomas: preclinical assessment in mouse GL261 and human G55 xenograft glioma models

Background

Despite current therapies, glioblastoma is a devastating cancer, and validation of effective biomarkers for it will enable better diagnosis and therapeutic intervention for this disease. We recently discovered a new biomarker for high-grade gliomas, ELTD1 (epidermal growth factor, latrophilin, and 7 transmembrane domain-containing protein 1 on chromosome 1) via bioinformatics, and validated that ELTD1 protein levels are significantly higher in human and rodent gliomas. The focus of this study was to assess the effect on tumor growth of an antibody against ELTD1 in orthotopic, GL261, and G55 xenograft glioma models.

Methods

The effect of anti-ELTD1 antibody therapy was assessed by animal survival, MRI measured tumor volumes, MR angiography, MR perfusion imaging, and immunohistochemistry (IHC) characterization of microvessel density in mouse glioma models. Comparative treatments included anti-vascular endothelial growth factor (VEGF) and anti-c-Met antibody therapies, compared with untreated controls.

Results

Tumor volume and survival data in this study show that antibodies against ELTD1 inhibit glioma growth just as effectively or even more so compared with other therapeutic targets studied, including anti-VEGF antibody therapy. Untreated GL261 or G55 tumors were found to have significantly higher ELTD1 levels (IHC) compared with contralateral normal brain. The anti-angiogenic effect of ELTD1 antibody therapy was observed in assessment of microvessel density, as well as from MR angiography and perfusion measurements, which indicated that anti-ELTD1 antibody therapy significantly decreased vascularization compared with untreated controls.

Conclusions

Either as a single therapy or in conjunction with other therapeutic approaches, anti-ELTD1 antibodies could be a valuable new clinical anti-angiogenic therapeutic for high-grade gliomas.

Molecular pathology of adamantinomatous craniopharyngioma: review and opportunities for practice

Since the first identification of CTNNB1 mutations in adamantinomatous craniopharyngioma (ACP), much has been learned about the molecular pathways and processes that are disrupted in ACP pathogenesis. To date this understanding has not translated into tangible patient benefit.

The recent development of novel techniques and a range of preclinical models now provides an opportunity to begin to support treatment decisions and develop new therapeutics based on molecular pathology.

In this review the authors summarize many of the key findings and pathways implicated in ACP pathogenesis and discuss the challenges that need to be tackled to translate these basic science findings for the benefit of patients.

A new anti-glioma therapy, AG119: pre-clinical assessment in a mouse GL261 glioma model

BACKGROUND

High grade gliomas (HGGs; grades III and IV) are the most common primary brain tumors in adults, and their malignant nature ranks them fourth in incidence of cancer death. Standard treatment for glioblastomas (GBM), involving surgical resection followed by radiation and chemotherapy with temozolomide (TMZ) and the anti-angiogenic therapy bevacizumab, have not substantially improved overall survival. New therapeutic agents are desperately needed for this devastating disease. Here we study the potential therapeutic agent AG119 in a pre-clinical model for gliomas. AG119 possesses both anti-angiogenic (RTK inhibition) and antimicrotubule cytotoxic activity in a single molecule.

METHODS

GL261 glioma-bearing mice were either treated with AG119, anti-VEGF (vascular endothelial growth factor) antibody, anti c-Met antibody or TMZ, and compared to untreated tumor-bearing mice. Animal survival was assessed, and tumor volumes and vascular alterations were monitored with morphological magnetic resonance imaging (MRI) and perfusion-weighted imaging, respectively.

RESULTS

Percent survival of GL261 HGG-bearing mice treated with AG119 was significantly higher (p < 0.001) compared to untreated tumors. Tumor volumes (21-31 days following intracerebral implantation of GL261 cells) were found to be significantly lower for AG119 (p < 0.001), anti-VEGF (p < 0.05) and anti-c-Met (p < 0.001) antibody treatments, and TMZ-treated (p < 0.05) mice, compared to untreated controls. Perfusion data indicated that both AG119 and TMZ were able to reduce the effect of decreasing perfusion rates significantly (p < 0.05 for both), when compared to untreated tumors. It was also found that IC50 values for AG119 were much lower than those for TMZ in T98G and U251 cells.

CONCLUSIONS

These data support further exploration of the anticancer activity AG119 in HGG, as this compound was able to increase animal survival and decrease tumor volumes in a mouse GL261 glioma model, and that AG119 is also not subject to methyl guanine transferase (MGMT) mediated resistance, as is the case with TMZ, indicating that AG119 may be potentially useful in treating resistant gliomas.

Molecular oncogenesis of craniopharyngioma: current and future strategies for the development of targeted therapies

Craniopharyngiomas are benign intracranial tumors that arise in the suprasellar and intrasellar region in children and adults. They are associated with calcification on neuroimaging, endocrinopathies, vision problems, and recurrence following subtotal resection. Molecular studies into their genetic basis have been limited, and therefore targeted medical therapies for this tumor have eluded physicians. With the discovery of aberrant Wnt/β-catenin pathway signaling in the pathogenesis of the most common subtype of craniopharyngioma (adamantinomatous), the identification of candidate genes and proteins implicated in this cascade provide attractive targets for future therapies. The recent development of a genetically engineered animal model of this tumor may also serve as a platform for evaluating potential therapies prior to clinical trials in humans. Advances in understanding the molecular pathogenesis of tumor recurrence have also been made, providing clues to develop adjuvant and neoadjuvant therapies to couple with tumor resection for optimal response rates. Finally, advances in genomic technologies and next-generation sequencing will underlie the translation of these genetic and molecular studies from the bench to clinical practice. In this review, the authors present an analysis of the molecular oncogenesis of craniopharyngioma and current directions in the development of novel therapies for these morbid, yet poorly understood brain tumors.

Controlled release of imatinib mesylate from PLGA microspheres inhibit craniopharyngioma mediated angiogenesis

Poly(lactic-co-glycolic acid) microspheres loaded with imatinib mesylate has been developed as a new therapeutic strategy to prevent craniopharyngioma recurrence. Microspheres composed of different lactic/glycolic acid ratios, molecular weights and drug compositions were synthesized and loaded with imatinib mesylate by modified double-emulsion/solvent evaporation technique and subsequently characterized by particle-size distribution, scanning electron microscopy, encapsulation efficiency and in vitro drug release. Inhibitory potential of imatinib containing microspheres on tumor neovascularization was investigated on craniopharyngioma tumor samples by rat cornea angiogenesis assay. Results showed that microspheres in different LA:GA ratios [LA:GA 50:50 (G50), 75:25 (G25), 85:15 (G15)] considerably reduced neovascularization induced by recurrent tumor samples in an in vivo angiogenesis assay (P < 0.01). Our data indicate that local delivery of imatinib mesylate to the post-surgical tumoral cavity using biodegradable microspheres may be a promising biologically selective approach to prevent the recurrence of craniopharyngiomas, via inhibition of neovascularization.

Single and hypofractionated stereotactic radiotherapy with CyberKnife for craniopharyngioma

Craniopharyngiomas are slow-growing tumors found in the suprasellar region, with especially high incidence in Japanese children. Due to the location, proximity and adhesiveness of the tumor to adjacent critical structures, these tumors remain a significant clinical challenge. The purpose of this study was to evaluate the clinical outcome of single and hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for craniopharyngioma. Forty-three patients (21 men and 22 women; median age 44 years; range 3-85 years) were treated at two institutions. Three cases were treated in a single fraction to a marginal dose of 13-16 Gy. The other 40 cases were treated in 2-5 fractions to a marginal dose of 13-25 Gy. Tumor volumes ranged from 0.09 to 20.8 cm(3) (median 2.0 cm(3)). Toxicities were evaluated with the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up period was 40 months (range 12-92 months). The 3-year overall survival and local control rates were 100 and 85%, respectively. In-field cyst enlargement was observed in 9 patients. These tumors had significantly larger volumes (mean 6.9 cm(3); 95% confidence interval, CI, 2.8-10.9 cm(3)) than the 34 controlled tumors (2.9 cm(3); CI 1.5-4.3 cm(3)) (P = 0.02). Out-field tumor regrowth was observed in 4 patients. No radiation-induced symptomatic visual disorder or brain necrosis was observed. Hypopituitarism was observed in only 1 patient. Single and hypofractionated SRT using CyberKnife produced high tumor control rates with minimal complications. Hypofractionated SRT may be useful for protecting the visual nerve and neuroendocrine function, especially for tumors located near the optic pathways and for large tumors.

Molecular MRI assessment of vascular endothelial growth factor receptor-2 in rat C6 gliomas

Angiogenesis is essential to tumour progression and a precise evaluation of angiogenesis is important for tumour early diagnosis and treatment. The quantitative and dynamic in vivo assessment of tumour angiogenesis can be achieved by molecular magnetic resonance imaging (mMRI). Vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) are the main regulatory systems in angiogenesis and have been used as hot targets for radionuclide-based molecular imaging. However, little research has been accomplished in targeting VEGF/VEGFRs by mMRI. In our study, we aimed to assess the expression of VEGFR2 in C6 gliomas by using a specific molecular probe with mMRI. The differential uptake of the probe conjugated to anti-VEGFR2 monoclonal antibody, shown by varied increases in T(1) signal intensity during a 2 hr period, demonstrated the heterogeneous expression of VEGFR2 in different tumour regions. Microscopic fluorescence imaging, obtained for the biotin group in the probe with streptavidin-Cy3, along with staining for cellular VEGFR2 levels, laminin and CD45, confirmed the differential distribution of the probe which targeted VEGFR2 on endothelial cells. The angiogenesis process was also assessed using magnetic resonance angiography, which quantified tumour blood volume and provided a macroscopic view and a dynamic change of the correlation between tumour vasculature and VEGFR2 expression. Together these results suggest mMRI can be very useful in assessing and characterizing the expression of specific angiogenic markers in vivo and help evaluate angiogenesis associated with tumour progression.

The role of inflammation in the genesis of the cystic component of craniopharyngiomas

BACKGROUND

Craniopharyngioma accounts for 5-10% of childhood tumors and, despite of the benign histological features, its clinical course can be malignant because of critical anatomical relationships with neural and vascular structures and the possible morbidity associated to resection. Only a few studies have addressed the molecular characterization of the cyst fluid so far and the mechanisms of action of intracystic agents are not clearly understood yet.

METHODS

The acidic soluble proteins contained in the cystic fluid of six patients with cystic craniopharyngioma, three of them treated with intratumoral interferon-α, were analyzed. A high performance liquid chromatography electrospray ionization mass spectrometry analysis was performed.

FINDINGS

The antimicrobial peptides α-defensins 1-3 relevant for innate immunity were detected in the cystic fluid before the intratumoral treatment. Amount of peptides significantly decreased in cystic fluid during pharmacological treatment.

INTERPRETATION

Detection of α-defensins 1-3 excludes that cyst fluid formation can derive from disruption of blood-brain barrier and suggests the involvement of innate immune response in pathology of craniopharyngioma cyst formation. The reduction of α-defensins could derive both from direct antitumoral effect of interferon-α on squamous epithelial cells of craniopharyngioma cyst and from its immuno-modulatory effects on the recruitment of cells of innate immune systems. Interestingly, the clinical patient outcome well correlates with the gradual reduction of α-defensins 1-3 amount. Additional studies will be necessary to establish the role of these molecules in the pathogenesis of craniopharyngioma, and further investigations will be necessary to confirm the efficacy of the antitumoral activity of interferon-α.

Expression of angiogenic factors in craniopharyngiomas: implications for tumor recurrence

BACKGROUND

The primary treatment for craniopharyngiomas is total excision, but recurrence is common. However, current knowledge on the mechanisms of recurrence is limited.

OBJECTIVE

We hypothesized that recurrence is linked to the angiogenesis of the tumor. Recurrent and nonrecurrent tumor samples were compared with regard to expression of angiogenesis-related factors and angiogenic capacity in a corneal angiogenesis model.

METHODS

Specimens of 4 recurrent and 6 nonrecurrent tumors were selected from 57 patients with adamantinomatous craniopharyngiomas. Sections were immunohistochemically stained with antibodies for vascular endothelial growth factor (VEGF), fibronectin, fibroblast growth factor (FGF)-2, platelet-derived growth factor (PDGF)-A, PDGF-B, platelet-derived growth factor receptor (PDGFR)-alpha, and PDGFR-beta. Expression levels were graded using a 4-point scoring system and were compared. For corneal angiogenesis assay, tissue samples were inoculated in a micropocket created on the rat eye, and microvessels were counted on days 3, 5, 7, and 9 to evaluate angiogenic potential.

RESULTS

Expression of PDGFR-alpha and FGF-2 were significantly higher for recurrent tumors (P = .02 and P = .01). However, recurrent and nonrecurrent tumors did not differ in the expressions of other ligands and receptors (PDGF-A, PDGF-B, and PDGFR-beta). Recurrent tumors displayed a higher angiogenic potential starting from the fifth day of corneal angiogenesis assay.

CONCLUSION

These findings suggest a relationship between recurrence of craniopharyngiomas and angiogenesis. New treatment modalities with selective PDGFR-alpha blockers may represent a novel and effective therapeutic option for the treatment of craniopharyngiomas.

Molecular pathogenesis of craniopharyngioma: switching from a surgical approach to a biological one

Craniopharyngioma has long been considered a benign tumor because of its pathological aspect. This primordial view of craniopharyngioma fit with the primitive treatment attempts based on blind resection of the tumor each time it recurred. The limits of this management strategy were proven early by the high morbidity related to the resection and recurrence risk despite radical lesion removal. Nowadays, craniopharyngioma must be considered a complex molecular disease, and a detailed explanation of the mechanisms underlying its aggressive biological and clinical behavior, despite some benign pathological features, would be the first step toward defining the best management of craniopharyngioma. Indeed, advances in the knowledge of the molecular mechanisms at the base of craniopharyngioma oncogenesis will lead to comprehension of the critical checkpoints involved in neoplastic transformation. The final research target will be the definition of new biological agents able to reverse the neoplastic process by acting on these critical checkpoints. This biological approach will lead to a refined therapy combining higher efficacy and safety with lower morbidity. In this paper the authors reveal state-of-the-art comprehension of the molecular biology of craniopharyngioma and the consequent therapeutic implications.

Postoperative intracranial seeding of craniopharyngiomas--report of three cases and review of the literature

PURPOSE

Seeding of craniopharyngioma has been rarely reported. We present three cases that ectopically recurred with seeding along the surgical route and CSF spaces.

METHODS

The first patient was a 13-year-old boy who had initially undergone radical excision of a suprasellar and retrosellar craniopharyngioma by a right pterional approach. Postoperative MRI showed no evidence of residual tumor. Two years later, MRI revealed a local recurrence and in addition a separated cystic tumor on the right side adjacent to the middle cerebral artery consistent with seeding along the surgical route. Both tumors were removed by re-operation. On histopathological examination, both, the local recurrent tumor and the distant deposit turned out to be adamantinomatous craniopharyngiomas. The second patient was a 27-year-old woman who was operated on for the first time via a right pterional and 1 year later for a recurrent craniopharyngioma via a transsphenoidal approach. Two years later, MRI revealed a right fronto-lateral intracranial metastasis at the site of the former craniotomy, which was removed by re-craniotomy. This deposit in the operative pathway was found to be an adamantinomatous craniopharyngioma, as was the initial tumor. The third patient was a 42-year-old man who was operated on 10 years ago for the first time via a right fronto-temporal approach. The recent control MRT revealed a right parietal intracranial tumor with peripheral contrast enhancement, which was located distant to the former craniotomy. The tumor was removed and histopathological examination revealed an adamantinomatous craniopharyngioma in accordance with the initial tumor. Postoperatively, the three patients were neurologically intact.

CONCLUSION

Although craniopharyngiomas exhibit a benign histopathological pattern, cerebrospinal fluid seeding along the surgical route or along the CSF pathways has been observed. Ectopic recurrence of craniopharyngioma suggests that meticulous protection of the whole surgical field and careful handling of the tumor during the operation are required. It should be emphasized that long-term follow-up is mandatory, even in patients undergoing a total removal.

The cell-cycle kinetics of craniopharyngioma and its clinical significance

Craniopharyngioma (CP) is a pathologically benign tumor with high incidence of recurrence and poor prognosis. DNA ploidy, S-phase fraction (SPF), and G2 phase/mitosis phase + S phase (G2/M + S) measured by flow cytometry (FCM) have been shown to correlate with cell cycle characteristics and clinical prognosis of other tumors. By use of FCM and terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) peroxidase, we compared DNA content, SPF, G2/M + S, necrosis and apoptosis in non-recurrent and recurrent tumor cells of CP from 63 cases including 32 adamantine epitheliomas (AEs) and 31 squamous papillary tumors (SPTs), and the ultrastructure of the CP cell was observed by transmission electron microscopy. Although no obvious differences between DNA content and necrosis and apoptosis rate were observed in subgroups of CPs, SPF and G2/M + S for recurrent tumors were statistically higher than those for recurrence-free tumors, and the recurrence rate of AE tumors is higher than that of SPT. Therefore, CP cells are diploid, and SPF and G2/M + S are related to recurrence of CP.

Morphological and Ultrastructural Findings of Prognostic Impact in Craniopharyngiomas

Craniopharyngioma is a slow-growing epithelial tumor with an unpredictable tendency to recur. To verify the reliability in predicting the clinical outcome, some morphological and immunohistochemical findings were analyzed in 37 primitive tumors and in 6 recurrences (one recurred twice). All the tumors were surgically excised and all recurrences exhibited an adamantinomatous pattern; mitotic rate was low (< 5 x 10 HPF) in both recurrent and in nonrecurrent tumors. Primary tumors showed a mean positivity of 1.7% (range 0.3-2%) to PCNA vs. 4.1% (range 0.3-8%) in recurrences. The MIB-1 Labelling Index was: 22.12% in primary tumors, 27.5% in recurrences, 31.3% in adult nonrecurrent tumors, and 4.1% in the pediatric tumor. CD34 labeling vessels/field was 9.3 in primary tumors and 9.91 in the recurrences; VEGF expression was higher in recurrences than in primary tumors (40 vs. 25%). Ultrastructural analysis showed fenestrated endothelium with hydropic changes in VEGF-positive vessels. Lack of clear correlations between morphological or immuno-staining patterns and behavior suggests that these features have no prognostic value in adult as well as in pediatric craniopharyngiomas. In this study, the only results that may be related to the aggressiveness of tumor is the major vascularization in the recurrent tumors in which the vessels show also ultrastructural changes.

Immunohistochemical evaluation of the microvascular density through the expression of TGF-beta (CD 105/endoglin) and CD 34 receptors and expression of the vascular endothelial growth factor (VEGF) in oligodendrogliomas

Angiogenesis has been proposed as essential for the growth of solid tumors. The determinants of this process, the growth factors and the vascular endothelial receptors have brought a potential in the tumor prognostic determination as well as perspectives of "targets" for antiangiogenic therapy. In oligodendrogliomas (OL), angiogenesis is little known and/or has generated conflicting results. In order to clarify angiogenesis in OL, we have evaluated the immunohistochemical expression of vascular endothelial growth factor (VEGF) and the microvascular density (MVD) through the expression of TGF-beta (CD105/endoglin) (MVD-CD105) and CD34 (MVD-CD34) receptors using the Chalkley point method in 30 OL. No significant immune reaction was found for the VEGF. There was expression in <10% of tumor cells and/or staining of weak intensity in 15 (50.0%), >10% of cells and moderate intensity staining in 1 (3.33%), and negative expression in 14 (46.67%). If present, the expression was restricted to tumor and endothelial cells. Our findings suggest that VEGF has little influence on OL angiogenesis. All specimens showed CD105 and CD34 expression in the intratumor vascular endothelium, suggesting involvement of CD105 in OL angiogenesis. The mean +/- SD MVD-CD105 and MVD-CD34 were 10.83 +/- 2.24 and 11.00 +/- 2.76 in OL (P = 0.086; r = 0.319); 10.00 +/- 2.00 and 10.40 +/- 3.02 in OL grade II (n = 15) (P = 0.547; r = 0.105), and 11.67 +/- 2.22 and 11.53 +/- 2.45 in OL grade III (n = 15) (P = 0.817; r = 0.551), respectively. The absence of correlation between DMV-CD105, DMV-CD34 and tumor grades suggests that anti-CD105 and anti-CD34 antibodies have different vascular specificities. MVD-CD105 was greater in OL grade III than in OL grade II (P = 0.0032), indicating an increase in the vascular neoformation, something which must be evaluated as a possible prognostic factor in OL. Both TGF-beta and CD105 bring perspectives as "targets" for antiangiogenic treatments in OL.

Craniopharyngiomas

Craniopharyngiomas are epithelial tumors arising along the path of the craniopharyngeal duct and presenting with a variety of manifestations. Their optimal management remains a subject of debate. Currently, surgical excision followed by external beam irradiation is the main treatment option. Craniopharyngiomas are associated with significant long-term morbidity and mortality rates.

The Spectrum of Malignancy in Craniopharyngioma

Craniopharyngiomas are low-grade epithelial neoplasms occurring almost exclusively in the sellar/suprasellar region. Histologic malignancy is extremely rare; the literature consists mostly of isolated case reports. Herein, we report 3 patients with craniopharyngiomas exhibiting histologic malignancy, 2 of which received radiation therapy before its appearance. Hematoxylin and eosin-stained slides and selected immunohistochemical stains were reviewed in all cases. Microvessel density analysis was performed in case 2. The patients included 2 men and 1 woman, age 14, 31, and 58 years at presentation, respectively. All patients expired 3 months to 9 years after first resection and 3 to 9 months after identification of histologic malignancy. The latter developed after multiple recurrences and radiation therapy in 2 cases, but seemed to arise de novo in 1 case resembling odontogenic ghost cell carcinoma and lacking any definite low-grade craniopharyngioma precursor. The malignant component of the other 2 cases resembled squamous cell carcinoma and low-grade myoepithelial carcinoma, respectively. The MIB-1 labeling index was markedly increased in the malignant component in comparison with the low-grade precursor. Malignant transformation in craniopharyngiomas, although rare, does exist. It assumes varied histologic appearances, usually after multiple recurrences and radiation therapy, and has a near uniformly fatal outcome. De novo malignancy in odontogenic tumors of the sella is even more unusual, but also has an ominous prognosis.

Expression of human MCM6 and DNA Topo II alpha in craniopharyngiomas and its correlation with recurrence of the tumor

Craniopharyngioma often recurs after resection resulting in poor outcome for the affected patients. The reliable criteria for predicting the tumor behavior are still lacking. It has been suggested that proliferative potential of the tumor cells is necessary for recurrence. Present study evaluated the cell multiplication activity, which is possibly related to relapse in 32 patients with adamantine epithelioma (AE) and 31 patients with squamous papillary tumor (SP). For this tissue specimens from their primary and recurring tumors were collected and immunohistochemical analysis of the expression of minichromosome maintenance protein 6 (MCM6) and DNA topoisomerase II alphalpha (DNA Topo II alpha) in the tumor sections was performed by quantitative microscopy. It was found that the MCM6 label index (LI) was significantly higher in AE than that of SP, and in the primary tumors of both subtypes the LIs of tumors with recurrence were higher than those without recurrence. There was a strong linear positive correlation between MCM6 LI and DNA Topo II alpha LI (r = 0.713; p = 0.000) in the craniopharyngiomas studied. The median MCM6 LI of the total 20 recurrent craniopharyngiomas (31.49%) was not significantly different from that of their primary tumors (29.65%). The long term risk of tumor recurrence is higher in AE than SP and it is associated with MCM6 and DNA Topo II alpha expression.

Angiogenesis and cell proliferation in human craniopharyngioma xenografts in nude mice

OBJECT

Craniopharyngioma is one of the most common congenital tumors of the sellar and suprasellar regions and accounts for between 4 and 6% of all intracranial tumors. Its oncogenesis and biological behavior have not been well studied, and neither a cell line nor an animal model have been established. To better understand the tumor and improve its clinical management, the authors investigated the angiogenesis and cellular proliferation in subcutaneous craniopharyngioma xenografts obtained by implanting human tumor cells into athymic nude mice.

METHODS

Human craniopharyngioma cells obtained from surgical specimens were subcutaneously implanted into BALB/c-nu/nu nude mice to establish a preliminary animal model of a transplanted tumor. Immunohistochemical staining with streptavidin-peroxidase complex was used to identify the cell phenotype and to evaluate the angiogenesis and proliferation in the xenografts. Expression of cytokeratin, minichromosome maintenance deficient 6 (MCM6) protein, and endothelial cell marker CD34 on the xenograft sections were assayed quantitatively by computer-assisted microscopy. Twenty-seven surviving subcutaneous xenografts were obtained in 15 nude mice. The total implantation success rate was 28.12% (adamantine epithelioma [AE], 37.50%; squamous papillary tumor [SPT], 18.75%). Formation of capillaries and cell proliferation were observed in all of these xenografts. Microvessel density and degree of MCM6 immunostaining were positively correlated in the surviving grafts (r = 0.410, p < 0.05), but there was no significant difference in these variables between the AE and SPT groups (p > 0.05).

CONCLUSIONS

A preliminary animal model of human craniopharyngioma was established in the nude mouse by heterotopic implantation. Surviving xenografts maintained their vascularization and proliferation activities until harvesting at 12 weeks.

Clinico-pathological and immunohistochemical characteristics associated to recurrence/regrowth of craniopharyngiomas

BACKGROUND

Craniopharyngioma is a rare, benign epithelial brain tumor of the suprasellar region with a high rate of recurrence. Clinical and histopathological features that might be predictors of recurrence/regrowth have not been clearly delineated.

METHODS

We compared recurrence/regrowth of the tumors with the clinico-pathological characteristics, vascular density, cell proliferation index, and immunohistochemical profile (cytokeratins, epithelial membrane antigen [EMA], carcinoembrionary antigen [CEA], and laminin) of 47 patients with craniopharyngioma followed for more than 5 years.

RESULTS

Tumors were adamantinomatous in 42 cases (89%) and papillary squamous in 5 cases (11%). Immunoreactivity for cytokeratin 8/18/19 was positive in 64%; cytokeratin 5 in 42%; laminin 8 in 62%; and CEA in 21%. The cell proliferation index and vascular density were greater in adamantinomatous than in papillary tumors (22+/-6 versus 17+/-3, p=0.05; and 21+/-3 versus 17+/-3, p=0.037, respectively); they were neither related to recurrence nor to regrowth. No significant differences were found between adamantinomatous and papillary tumors regarding the presence of cytokeratin, laminin, CEA or glial fibrillary acidic protein (GFAP). Recurrence rate at 5 years was 59%. No relation was found between recurrence and adjuvant radiotherapy (AR). Residual tumor after surgery, whorl-like arrays (p=0.04) and immunoreactivity for p53 (p=0.022) were significantly related to recurrence/regrowth.

CONCLUSIONS

Residual tumor after surgery, immunoreactivity to p53 and presence of whorl-like arrays are associated to recurrence/regrowth of craniopharyngioma.

Craniopharyngiomas

Craniopharyngiomas are rare, mainly sellar/parasellar, epithelial tumors diagnosed during childhood or adult life. Histologically, two primary subtypes have been recognized (adamantinomatous and papillary) with an as yet, unclarified pathogenesis. They may present with a variety of manifestations (neurological, visual, and hypothalamo-pituitary). Despite their benign histological appearance, they often show an unpredictable growth pattern, which, combined with the lack of randomized studies, poses significant difficulties in the establishment of an optimal therapeutic protocol. This should focus on the prevention of recurrence(s), improvement of survival, reduction of the significant disease and treatment-related morbidity (endocrine, visual, hypothalamic, neurobehavioral, and cognitive), and preservation of the quality of life. Currently, surgical excision followed by external beam irradiation, in cases of residual tumor, is the main treatment option. Intracystic irradiation or bleomycin, stereotactic radiosurgery, or radiotherapy and systemic chemotherapy are alternative approaches; their place in the management plan remains to be assessed in adequately powered long-term trials. Apart from the type of treatment, the identification of clinical and imaging parameters that will predict patients with a better prognosis is difficult. The central registration of patients with these challenging tumors may provide correlates between treatments and outcomes and establish prognostic factors at the pathological or molecular level that may further guide us in the future.

Modulation of VEGF/Flk-1 receptor expression in the rat pituitary GH3 cell line by growth factors

Both vascular endothelial growth factor (VEGF) and its receptor Flk-1 are expressed in normal pituitary cells and in the prolactin- and growth hormone-producing GH3 cell line of the rat, thus suggesting autocrine/paracrine function. Regulation of the Flk-1 receptor system in pituitary cells is poorly understood, but evidence suggests that up-regulated growth factors play a role in its expression and activation. To study the role of growth factors in this process, we examined changes in VEGF and Flk-1 expression in GH3 cells following varied exposure to betaFGF, EGF, and TGFbeta1. Immunofluorescence labelling and laser scanning cytometry were used to measure changes in VEGF and Flk-1 expression. Results showed that betaFGF, EGF and TGFbeta up-regulated the VEGF/FLK-1 receptor system. Distinct patterns of activation were detected. At 2 hours, EGF and TGFbeta caused no significant changes in VEGF and Flk-1 expression; however, betaFGF up-regulated VEGF expression in 99% of cells but only induced modest changes in Flk-1 overexpression. A similar percentage of cells overexpressed VEGF after 24-hour incubation with betaFGF, but more prominent Flk-1 overexpression was detected. At 24 hours, EGF and TGFbeta1 induced a significant increase in both VEGF and Flk-1 expression. In summary, our findings show that VEGF/Flk-1 expression in pituitary cells may be altered by different growth factors. This may affect angiogenesis and the progression of pituitary tumors.

Anti-angiogenic Therapy in Pediatric Neuro-oncology

In order to grow, tissues require additional nutrients and oxygen as well as removal of waste products. Tumors achieve this by up-regulating angiogenic cytokines and/or down-regulating natural inhibitory proteins that allow neovascularization to proceed. Brain tumors continue to account for significant morbidity and mortality, in spite of significant advances in neurosurgical and radiation techniques and new chemotherapy combinations. As such, there is a real and immediate need for novel biologic therapies that can target these tumors. A number of new drugs that target different aspects of the angiogenic cascade have been identified and are now in clinical trials in children with primary brain tumors. In many of these pre-clinical and clinical studies, anti-angiogenic therapy has been well tolerated, has lacked many of the traditional toxicities of radiation and chemotherapy, does not require blood-brain barrier penetration, and targets a critical pathway in central nervous system tumor development. This review will discuss what angiogenesis is, how pediatric brain tumors regulate angiogenesis to obtain a vascular supply, what types of inhibitors are available, how different classes of inhibitors work, the types of resistance possible, how rapidly these inhibitors may work, and what surrogate markers of activity are available to follow response.

Angiogenesis and cerebral neoplasia

Angiogenesis is a fundamental process in reproduction and wound healing. It is a tightly regulated process causing neovascularization. However, if angiogenesis becomes unregulated, it may be responsible for several disease processes such as brain tumour growth and metastasis. An understanding of the factors implicated in angiogenesis and its inhibition is essential if they are to be exploited as possible clinical treatments for brain tumours. Unfortunately, there are multiple factors known to be involved in the regulation of angiogenesis, and hence, the clinical application of any single agent may not be effective. This article summarizes the processes of blood vessel formation in the brain, examines the angiogenic factors that are important in the nervous system and discusses their role in brain tumour development and possible treatment.

Halofuginone inhibits angiogenesis and growth in implanted metastatic rat brain tumor model--an MRI study

Tumor growth and metastasis depend on angiogenesis; therefore, efforts are made to develop specific angiogenic inhibitors. Halofuginone (HF) is a potent inhibitor of collagen type alpha1(I). In solid tumor models, HF has a potent antitumor and antiangiogenic effect in vivo, but its effect on brain tumors has not yet been evaluated. By employing magnetic resonance imaging (MRI), we monitored the effect of HF on tumor progression and vascularization by utilizing an implanted malignant fibrous histiocytoma metastatic rat brain tumor model. Here we demonstrate that treatment with HF effectively and dose-dependently reduced tumor growth and angiogenesis. On day 13, HF-treated tumors were fivefold smaller than control (P < .001). Treatment with HF significantly prolonged survival of treated animals (142%; P = .001). In HF-treated rats, tumor vascularization was inhibited by 30% on day 13 and by 37% on day 19 (P < .05). Additionally, HF treatment inhibited vessel maturation (P = .03). Finally, in HF-treated rats, we noticed the appearance of a few clusters of satellite tumors, which were distinct from the primary tumor and usually contained vessel cores. This phenomenon was relatively moderate when compared to previous reports of other antiangiogenic agents used to treat brain tumors. We therefore conclude that HF is effective for treatment of metastatic brain tumors.

Monitoring the Expression Profiles of Integrins and Adhesion/Growth-regulatory Galectins in Adamantinomatous Craniopharyngiomas: Their Ability to Regulate Tumor Adhesiveness to Surrounding Tissue and Their Contribution to Prognosis

OBJECTIVE

The purpose of this study was to identify biological markers that may be involved in the adhesiveness of craniopharyngiomas to optical chiasms and/or pituitary stalks.

METHODS

We determined the complete pattern of integrin expression in three craniopharyngiomas by means of a complementary deoxyribonucleic acid microarray. We quantitatively determined the levels of immunohistochemical expression of the different integrins in a series of 37 cases and the pattern of immunohistochemical expression of 10 extracellular matrix components (acting as integrin ligands) in 7 optical chiasms and 11 pituitary stalks. We also quantitatively (computer-assisted microscopy) determined the levels of immunohistochemical expression of galectin-1, -3, -4, -7, and -8 in 50 adamantinomatous craniopharyngiomas.

RESULTS

The present study shows that at both the ribonucleic acid and protein levels, adamantinomatous craniopharyngiomas express the alpha2, alpha6, alpha(v), beta1, beta5, and beta8 integrin subunits, whereas optical chiasms and pituitary stalks express vitronectin, thrombospondin, and various forms of collagens.

CONCLUSION

Our data suggest that at least part of the adhesiveness of craniopharyngiomas to the surrounding tissue, such as optical chiasms and pituitary stalks, could be explained by the interactions between alpha(2beta1) integrin expressed by craniopharyngiomas and collagens on the one hand, and vitronectin expressed by the surrounding tissue on the other hand. In addition, a Cox regression analysis has revealed that the levels of galectin-4 contribute significant information toward the delay in recurrence independently of surgical status.

Angiogenesis and the growth potential of craniopharyngiomas

The present study was performed to evaluate the role of neovascularization on the behavior of craniopharyngiomas as well as the contribution of endothelial cell proliferation and migration in the remodeling and expansion of the vascular network associated with angiogenesis. Fourteen primary tumors were studied, all of the adamantinomatous type. CD34 immunostaining, an endothelial cell marker, localized vessels within the connective tissue stroma. MIB-1 immunopositivity was apparent in the nuclei of neoplastic cells, few endothelial cells, and stromal elements. MIB-1 counts were higher in epithelial than connective tissue cells. A positive correlation was found between the number of MIB-1 immunopositive cells and microvessel density (MVD). Immunohistochemistry demonstrated that integrin alphavbeta3 expression was restricted to tumor vasculature; the tumor cells were immunonegative. Only 2.5% of vessels detected with CD34 were immunopositive for integrin alphavbeta3. At present, no therapeutic implications can be drawn from our observations. More studies are needed to assess whether integrin alphavbeta3 antagonists or drugs that arrest the cell cycle of endothelial cells can inhibit angiogenesis in craniopharyngiomas.

Cathepsin B, D and K expression in adamantinomatous craniopharyngiomas relates to their levels of differentiation as determined by the patterns of retinoic acid receptor expression

AIMS

To investigate the potential predictive value of cathepsins B, D and K in a series of 51 adamantinomatous craniopharyngiomas. While almost always benign, craniopharyngiomas exhibit a high propensity to recur postsurgically and biological markers are therefore needed to predict their recurrence. We have previously demonstrated the potential predictive value of retinoic acid receptors (RARs) (Lefranc et al., J. Neurosurg. 2003; 98; 145-153).

METHODS AND RESULTS

Computer-assisted microscopy was used to determine quantitatively the immunohistochemical levels of expression of the alpha, beta and gamma RAR subtypes and cathepsins B, D and K. The levels of expression of cathepsin D and of cathepsin B correlated significantly with the levels of expression of RARbeta. The levels of expression of cathepsin K correlated significantly with the levels of expression of RARgamma.

CONCLUSIONS

Recurrent adamantinomatous craniopharyngiomas are characterized by low levels of RARbeta and high levels of RARgamma. The tendency to recurrence seems, at least partly, to relate to the fact that (i) craniopharyngiomas with low levels of RARbeta express low levels of cathepsin D, and (ii) craniopharyngiomas with high levels of RARgamma express high levels of cathepsin K.

Angiogenic factors in the central nervous system

The past decade has seen considerable advances in the understanding of angiogenesis. Blood vessel development and growth in the central nervous system are tightly controlled processes that are regulated by angiogenic factors. Angiogenic factors have been implicated in the pathogenesis of a wide variety of disorders, including primary and metastatic brain tumors, aneurysms, arteriovenous malformations, and cavernous malformations. The potential clinical applications of angiogenesis research include inhibition of angiogenesis to control brain tumors and therapeutic angiogenesis to promote collateral blood vessel formation among patients at risk of ischemia. This article summarizes the processes of blood vessel formation in the brain, examines the angiogenic factors that are prominent in the central nervous system, reviews the clinical use of angiogenesis inhibitors, and identifies areas for future investigation.