Clinical experience with alpha-particle emitting 211At: treatment of recurrent brain tumor patients with 211At-labeled chimeric antitenascin monoclonal antibody 81C6

alpha-Particle-emitting radionuclides, such as (211)At, with a 7.2-h half-life, may be optimally suited for the molecularly targeted radiotherapy of strategically sensitive tumor sites, such as those in the central nervous system. Because of the much shorter range and more potent cytotoxicity of alpha-particles than of beta-particles, (211)At-labeled agents may be ideal for the eradication of tumor cells remaining after surgical debulking of malignant brain tumors. The main goal of this study was to investigate the feasibility and safety of this approach in patients with recurrent malignant brain tumors.

METHODS

Chimeric antitenascin monoclonal antibody 81C6 (ch81C6) (10 mg) was labeled with 71-347 MBq of (211)At by use of N-succinimidyl 3-[(211)At]astatobenzoate. Eighteen patients were treated with (211)At-labeled ch81C6 ((211)At-ch81C6) administered into a surgically created resection cavity (SCRC) and then with salvage chemotherapy. Serial gamma-camera imaging and blood sampling over 24 h were performed.

RESULTS

A total of 96.7% +/- 3.6% (mean +/- SD) of (211)At decays occurred in the SCRC, and the mean blood-pool percentage injected dose was < or = 0.3. No patient experienced dose-limiting toxicity, and the maximum tolerated dose was not identified. Six patients experienced grade 2 neurotoxicity within 6 wk of (211)At-ch81C6 administration; this neurotoxicity resolved fully in all but 1 patient. No toxicities of grade 3 or higher were attributable to the treatment. No patient required repeat surgery for radionecrosis. The median survival times for all patients, those with glioblastoma multiforme, and those with anaplastic astrocytoma or oligodendroglioma were 54, 52, and 116 wk, respectively.

CONCLUSION

This study provides proof of concept for regional targeted radiotherapy with (211)At-labeled molecules in oncology. Specifically, the regional administration of (211)At-ch81C6 is feasible, safe, and associated with a promising antitumor benefit in patients with malignant central nervous system tumors.

Targeting methylguanine-DNA methyltransferase in the treatment of neuroblastoma

PURPOSE

The combination of temozolomide and irinotecan has preclinical schedule-dependent synergy against neuroblastoma but is not curative for relapsed high-risk patients. We hypothesized that the DNA repair protein methylguanine-DNA methyltransferase (MGMT) is an important resistance factor, and that inactivation of MGMT would sensitize neuroblastoma cells to these agents.

EXPERIMENTAL DESIGN

MGMT protein expression was assessed in 74 primary neuroblastoma tumors. Growth inhibition assays were done to determine the IC(50) and the extent of synergy observed with various concentrations of temozolomide, irinotecan, and the MGMT-inactivating agent O(6)-benzylguanine, using cultured syngeneic neuroblastoma cells with either low or high levels of MGMT expression. We then assessed efficacy in a mouse xenograft model of metastatic neuroblastoma.

RESULTS

MGMT was expressed by all 74 tumors evaluated. Pretreatment of neuroblastoma cells with O(6)-benzylguanine reduced the IC(50) of temozolomide by 10-fold regardless of level of MGMT expression, and pretreatment with BG followed by temozolomide + irinotecan further reduced the IC(50) in cells with high MGMT expression another 10-fold, to well below clinically achievable concentrations. The combination index was 0.27 to 0.30 for all three drugs in both cell lines, indicating strong synergy. Survival at 100 days for mice with metastatic neuroblastoma was 56% with three-drug treatment, compared with untreated controls (0%, P < 0.001) or temozolomide + irinotecan (10%, P = 0.081).

CONCLUSIONS

MGMT is widely expressed in primary neuroblastoma tumors, and is a relevant therapeutic target. Both in vitro and in vivo studies suggest inactivation of MGMT with O(6)-benzylguanine may increase the activity of temozolomide and irinotecan against neuroblastoma.

Stem cell-like glioma cells promote tumor angiogenesis through vascular endothelial growth factor

Malignant gliomas are highly lethal cancers dependent on angiogenesis. Critical tumor subpopulations within gliomas share characteristics with neural stem cells. We examined the potential of stem cell-like glioma cells (SCLGC) to support tumor angiogenesis. SCLGC isolated from human glioblastoma biopsy specimens and xenografts potently generated tumors when implanted into the brains of immunocompromised mice, whereas non-SCLGC tumor cells isolated from only a few tumors formed secondary tumors when xenotransplanted. Tumors derived from SCLGC were morphologically distinguishable from non-SCLGC tumor populations by widespread tumor angiogenesis, necrosis, and hemorrhage. To determine a potential molecular mechanism for SCLGC in angiogenesis, we measured the expression of a panel of angiogenic factors secreted by SCLGC. In comparison with matched non-SCLGC populations, SCLGC consistently secreted markedly elevated levels of vascular endothelial growth factor (VEGF), which were further induced by hypoxia. In an in vitro model of angiogenesis, SCLGC-conditioned medium significantly increased endothelial cell migration and tube formation compared with non-SCLGC tumor cell-conditioned medium. The proangiogenic effects of glioma SCLGC on endothelial cells were specifically abolished by the anti-VEGF neutralizing antibody bevacizumab, which is in clinical use for cancer therapy. Furthermore, bevacizumab displayed potent antiangiogenic efficacy in vivo and suppressed growth of xenografts derived from SCLGC but limited efficacy against xenografts derived from a matched non-SCLGC population. Together these data indicate that stem cell-like tumor cells can be a crucial source of key angiogenic factors in cancers and that targeting proangiogenic factors from stem cell-like tumor populations may be critical for patient therapy.

Second messenger systems in human gliomas

CONTEXT

Patients with glioblastoma (astrocytoma, World Health Organization grade IV) exhibit 2-year survival rates of less than 20% despite significant advances in therapeutic options available to patients. Epidermal growth factor receptor (EGFR) hyperexpression is one of the most commonly encountered abnormalities in this tumor. However, EGFR expression, amplification, and mutations are poorly predictive of patient survival. Investigators have taken to exploiting the sensitivities of activated downstream targets in the EGFR second messenger pathways to certain inhibitory drugs to downregulate their neoplastic messages promoting cell growth and inhibiting cell death.

OBJECTIVE

It is important to both gain some understanding of the functional significance of these pathways and to understand the role the pathologist might play in characterizing the activation status of certain downstream messenger proteins that are targeted in these brain tumor therapies. We have reviewed the literature regarding histologic assays that have been incorporated into trials of these new drugs and report on the methods used to study these proteins and the conclusions of these studies.

DATA SOURCES

Literature review and primary material from Duke University (Durham, NC) Department of Pathology archives.

CONCLUSIONS

To date, drug trial reports indicate that identification of the presence of the EGFR variant, EGFRvIII, and measurement of the activated downstream targets, phospho-Akt, phospho-S6, and phospho-MAPK, may be useful in predicting sensitivity to some of the EGFR kinase inhibitors. No studies to date have identified prognostic significance related to immunoreactivity status among any of these markers that is independent of histologic grade.

Sensitive detection of human cytomegalovirus in tumors and peripheral blood of patients diagnosed with glioblastoma

Human cytomegalovirus (HCMV) has been described to be associated with several human malignancies, though the frequency of detection remains controversial. It is unclear whether HCMV plays an active role in malignant tumor progression or becomes reactivated under pathologic conditions that result in chronic inflammation or immunosuppression. In this study, we report on the investigation of detecting HCMV in the tumors and peripheral blood of patients with newly diagnosed glioblastoma multiforme (GBM). Using immunohistochemistry, in situ hybridization, and polymerase chain reaction amplification of viral DNA, the detection of HCMV was investigated in tumor and blood specimens from patients with GBM as well as in the peripheral blood of normal volunteers and patients undergoing craniotomy for diagnoses other than GBM. We found that a high percentage (>90%) of GBM tumors, not surrounding normal brain, are associated with HCMV nucleic acids and proteins. Furthermore, a significant proportion of patients (80%) with newly diagnosed GBM have detectable HCMV DNA in their peripheral blood, while sero-positive normal donors and other surgical patients did not exhibit detectable virus, suggesting either a systemic reactivation of HCMV within patients with GBM or shedding of viral DNA from infected tumor cells into the periphery. These results confirm the association of HCMV with malignant gliomas and demonstrate that subclinical HCMV viremia (presence of viral DNA in blood without clinical symptoms of infection) is a previously unrecognized disease spectrum in patients with GBM.

Tumor resection cavity administered iodine-131-labeled antitenascin 81C6 radioimmunotherapy in patients with malignant glioma: neuropathology aspects

INTRODUCTION

The neurohistological findings in patients treated with targeted beta emitters such as (131)I are poorly described. We report a histopathologic analysis from patients treated with combined external beam therapy and a brachytherapy consisting of a (131)I-labeled monoclonal antibody (mAb) injected into surgically created resection cavities during brain tumor resections.

METHODS

Directed tissue samples of the cavity walls were obtained because of suspected tumor recurrence from 28 patients. Samples and clinical follow-up were evaluated on all patients (Group A) based on total radiation dose received and a subset of these (n=18; Group B, proximal therapy subset) who had received external beam therapy within <or=3 months of mAb therapy and undergoing 26 biopsies over 37 months. Histologic outcomes were "proliferative glioma," "quiescent glioma" and negative for neoplasm. Statistical analysis was used to assess the casual relation between total absorbed dose ((131)I-mAb+external beam) and histologic diagnosis.

RESULTS

The lesions observed after (131)I-mAb therapy were qualitatively similar to those reported for other types of radiation therapy; however, the high localized dose rate and absorbed doses produced by the short range of (131)I beta particles seem to have resulted in an earlier necrotic reaction in the tumor bed. Among all 28 (Group A) patients, median survival from tissue analysis after mAb therapy depended on histopathology and total radiation absorbed dose. Median survival for patients with tissue classified as proliferative glioma, quiescent glioma and negative for neoplasm were 3.5, 15 and 27.5 months, respectively. Without categorization, total dose was a significant predictor of survival (P<.002) where patients with higher doses had better prognoses. For example, median survival in patients receiving a total radiation dose greater than 86 Gy was 19 months compared with 7 months for those receiving less than 86 Gy.

CONCLUSIONS

Histopathologic analysis correlated with prognosis. Among all patients (Group A) there was a significant correlation between biopsy outcome, survival, and total radiation absorbed dose. Among the Group B proximal therapy patients, the neuropathologic changes were qualitatively similar to those described for external beam therapy and interstitial brachytherapy.

Phase II study of imatinib mesylate and hydroxyurea for recurrent grade III malignant gliomas

PURPOSE

Recent reports demonstrate the activity of imatinib mesylate, an ATP-mimetic, tyrosine kinase inhibitor, plus hydroxyurea, a ribonucleotide reductase inhibitor, in patients with recurrent glioblastoma multiforme. We performed the current phase 2 study to evaluate this regimen among patients with recurrent WHO grade III malignant glioma (MG).

PATIENTS AND METHOD

Patients with grade III MG at any recurrence, received imatinib mesylate plus hydroxyurea (500 mg twice a day) orally on a continuous, daily schedule. The imatinib mesylate dose was 500 mg twice a day for patients on enzyme inducing anti-epileptic drugs (EIAEDs) and 400 mg once a day for those not on EIAEDs. Clinical assessments were performed monthly and radiographic assessments were obtained at least every 2 months. The primary endpoint was 6-month progression-free survival (PFS) rate.

RESULTS

Thirty-nine patients were enrolled. All patients had progressive disease after prior radiotherapy and at least temozolomide-based chemotherapy. The median number of episodes of prior progression was 2 (range, 1-7) and the median number of prior treatment regimens was 3 (range, 1-8). With a median follow-up of 82.9 weeks, 24% of patients were progression-free at 6 months. The radiographic response rate was 10%, while 33% achieved stable disease. Among patients who achieved at least stable disease at first evaluation, the 6-month and 12-month PFS rates were 53% and 29%, respectively. The most common grade 3 or greater toxicities were hematologic and complicated less than 4% of administered courses.

CONCLUSION

Imatinib mesylate plus hydroxyurea, is well tolerated and associated with anti-tumor activity in some patients with recurrent grade 3 MG.

Cerebellopontine angle craniopharyngioma: case report and literature review

The authors report an unusual case of adamantinomatous craniopharyngioma occurring in isolation in the cerebellopontine angle of a 12-year-old female. The patient presented with a 1-year history of nausea, vomiting, and headache. MRI revealed a left cerebellopontine angle tumor without connection to the suprasellar space. Following near-total resection, histological review confirmed the lesion as an adamantinomatous craniopharyngioma. This is only the third published report of craniopharyngioma occurring in isolation in the cerebellopontine angle. The case report and a brief review of the literature are presented.

Glioma stem cells promote radioresistance by preferential activation of the DNA damage response

Ionizing radiation represents the most effective therapy for glioblastoma (World Health Organization grade IV glioma), one of the most lethal human malignancies, but radiotherapy remains only palliative because of radioresistance. The mechanisms underlying tumour radioresistance have remained elusive. Here we show that cancer stem cells contribute to glioma radioresistance through preferential activation of the DNA damage checkpoint response and an increase in DNA repair capacity. The fraction of tumour cells expressing CD133 (Prominin-1), a marker for both neural stem cells and brain cancer stem cells, is enriched after radiation in gliomas. In both cell culture and the brains of immunocompromised mice, CD133-expressing glioma cells survive ionizing radiation in increased proportions relative to most tumour cells, which lack CD133. CD133-expressing tumour cells isolated from both human glioma xenografts and primary patient glioblastoma specimens preferentially activate the DNA damage checkpoint in response to radiation, and repair radiation-induced DNA damage more effectively than CD133-negative tumour cells. In addition, the radioresistance of CD133-positive glioma stem cells can be reversed with a specific inhibitor of the Chk1 and Chk2 checkpoint kinases. Our results suggest that CD133-positive tumour cells represent the cellular population that confers glioma radioresistance and could be the source of tumour recurrence after radiation. Targeting DNA damage checkpoint response in cancer stem cells may overcome this radioresistance and provide a therapeutic model for malignant brain cancers.

Quantitative analysis of O6-alkylguanine-DNA alkyltransferase in malignant glioma

Promoter hypermethylation of the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT) has been associated with an enhanced response to chloroethylating and methylating agents in patients with malignant glioma. The purpose of this study was to compare three distinct yet related indices for measuring AGT to determine if these assays could be used interchangeably when AGT status is to be used to guide chemotherapeutic decisions. Real-time methylation-specific PCR (MSP), assessed as the ratio of methylated AGT copies to internal beta-actin control, was used to quantitate AGT hypermethylation in 32 glioma samples. Data were compared with AGT enzyme activity as well as immunohistochemical detection of AGT protein from the same samples. Hypermethylation of the AGT promoter was detected in 19 of 31 (61%) samples evaluable by MSP. Low-level AGT, defined as <20% nuclear AGT staining by immunohistochemistry, was found in 10 of 32 samples (31%), whereas 12 of 32 (38%) had low levels of AGT activity. Correlation of immunohistochemistry to AGT activity was statistically significant (P = 0.014) as was the correlation of immunohistochemistry to MSP (P = 0.043), whereas MSP compared with AGT activity (P = 0.246) was not significant. Cross-tabulation of immunohistochemistry and MSP data based on prognostic groups, where good prognosis was represented by an immunohistochemistry of <20% and an MSP ratio >12, showed no significant relationship (P = 0.214), suggesting that one assay cannot be used interchangeably for another. The observed discordance between respective measures of AGT based on prognosis supports further standardization of AGT assays designed to guide therapeutic practice. The data also suggest that consideration be given to the large population of AGT-expressing cells within samples when therapeutic strategies based on tumor methylation are used.

AAL881, a Novel Small Molecule Inhibitor of RAF and Vascular Endothelial Growth Factor Receptor Activities, Blocks the Growth of Malignant Glioma

Malignant gliomas are highly proliferative and angiogenic cancers resistant to conventional therapies. Although RAS and RAF mutations are uncommon in gliomas, RAS activity is increased in gliomas. Additionally, vascular endothelial growth factor and its cognate receptors are highly expressed in gliomas. We now report that AAL881, a novel low-molecular weight inhibitor of the kinase activities associated with B-RAF, C-RAF (RAF-1), and VEGF receptor-2 (VEGFR2), showed activity against glioma cell lines and xenografts. In culture, AAL881 inhibited the downstream effectors of RAF in a concentration-dependent manner, with inhibition of proliferation associated with a G(1) cell cycle arrest, induction of apoptosis, and decreased colony formation. AAL881 decreased the proliferation of bovine aortic endothelial cells as well as the tumor cell secretion of vascular endothelial growth factor and inhibited the invasion of glioma cells through an artificial extracellular matrix. Orally administered AAL881 was well tolerated with minimal weight loss in non-tumor-bearing mice. Established s.c. human malignant glioma xenografts grown in immunocompromised mice treated with a 10-day course of oral AAL881 exhibited growth delays relative to control tumors, frequently resulting in long-term complete regressions. AAL881 treatment extended the survival of immunocompromised mice bearing orthotopic glioma xenografts compared with placebo controls. The intraparenchymal portions of orthotopic AAL881-treated tumors underwent widespread necrosis consistent with vascular disruption compared with the subarachnoid elements. These effects are distinct from our prior experience with VEGFR2 inhibitors, suggesting that targeting RAF itself or in combination with VEGFR2 induces profound tumor responses in gliomas and may serve as a novel therapeutic approach in patients with malignant gliomas.

Novel human IgG2b/murine chimeric antitenascin monoclonal antibody construct radiolabeled with 131I and administered into the surgically created resection cavity of patients with malignant glioma: phase I trial results

Results from animal experiments have shown that human IgG2/mouse chimeric antitenascin 81C6 (ch81C6) monoclonal antibody exhibited higher tumor accumulation and enhanced stability compared with its murine parent. Our objective was to determine the effect of these differences on the maximum tolerated dose (MTD), pharmacokinetics, dosimetry, and antitumor activity of (131)I-ch81C6 administered into the surgically created resection cavity (SCRC) of malignant glioma patients.

METHODS

In this phase I trial, eligible patients received a single injection of (131)I-ch81C6 administered through a Rickham catheter into the SCRC. Patients were stratified as newly diagnosed and untreated (stratum A), newly diagnosed after external beam radiotherapy (XRT) (stratum B), and recurrent (stratum C). (131)I-ch81C6 was administered either before (stratum A) or after (stratum B) conventional XRT for newly diagnosed patients. In addition, chemotherapy was prescribed for all patients after (131)I-ch81C6 administration. Dose escalation was performed independently for each stratum. Patients were observed for toxicity and response until death or progressive disease.

RESULTS

We treated 47 patients with (131)I-ch81C6 doses up to 4.44 GBq (120 mCi), including 35 with newly diagnosed tumors (strata A and B) and 12 with recurrent disease (stratum C). Dose-limiting hematologic toxicity defined the MTD to be 2.96 GBq (80 mCi) for all patients, regardless of treatment strata. Neurologic dose-limiting toxicity developed in 3 patients; however, none required further surgery to debulk radiation necrosis. Median survival was 88.6 wk and 65.0 wk for newly diagnosed and recurrent patients, respectively.

CONCLUSION

The MTD of (131)I-ch81C6 is 2.96 GBq (80 mCi) because of dose-limiting hematologic toxicity. Although encouraging survival was observed, (131)I-ch81C6 was associated with greater hematologic toxicity, probably due to the enhanced stability of the IgG2 construct, than previously observed with (131)I-murine 81C6.

Errors in surgical neuropathology and the influence of cognitive biases: the psychology of intelligence analysis

CONTEXT

A significant difficulty that pathologists encounter in arriving at a correct diagnosis is related to the way information from various sources is processed and assimilated in context.

OBJECTIVE

These issues are addressed by the science of cognitive psychology. Although cognitive biases are the focus of a number of studies on medical decision making, few if any focus on the visual sciences.

DATA SOURCES

A recent publication authored by Richards Heuer, Jr, The Psychology of Intelligence Analysis, directly addresses many of the cognitive biases faced by neuropathologists and anatomic pathologists in general. These biases include visual anticipation, first impression, and established mindsets and subconsciously influence our critical decision-making processes.

CONCLUSIONS

The book points out that while biases are an inherent property of cognition, the influence of such biases can be recognized and the effects blunted.

Salvage radioimmunotherapy with murine iodine-131-labeled antitenascin monoclonal antibody 81C6 for patients with recurrent primary and metastatic malignant brain tumors: phase II study results

PURPOSE

To assess the efficacy and toxicity of intraresection cavity iodine-131-labeled murine antitenascin monoclonal antibody 81C6 (131I-m81C6) among recurrent malignant brain tumor patients.

PATIENTS AND METHODS

In this phase II trial, 100 mCi of 131I-m81C6 was injected directly into the surgically created resection cavity (SCRC) of 43 patients with recurrent malignant glioma (glioblastoma multiforme [GBM], n = 33; anaplastic astrocytoma [AA], n = 6; anaplastic oligodendroglioma [AO], n = 2; gliosarcoma [GS], n = 1; and metastatic adenocarcinoma, n = 1) followed by chemotherapy.

RESULTS

With a median follow-up of 172 weeks, 63% and 59% of patients with GBM/GS and AA/AO tumors were alive at 1 year. Median overall survival for patients with GBM/GS and AA/AO tumors was 64 and 99 weeks, respectively. Ten patients (23%) developed acute hematologic toxicity. Five patients (12%) developed acute reversible neurotoxicity. One patient (2%) developed irreversible neurotoxicity. No patients required reoperation for radionecrosis.

CONCLUSION

In this single-institution phase II study, administration of 100 mCi of 131I-m81C6 to recurrent malignant glioma patients followed by chemotherapy is associated with a median survival that is greater than that of historical controls treated with surgery plus iodine-125 brachytherapy. Furthermore, toxicity was acceptable. Administration of a fixed millicurie dose resulted in a wide range of absorbed radiation doses to the SCRC. We are now conducting a phase II trial, approved by the US Food and Drug Administration, using patient-specific 131I-m81C6 dosing, to deliver 44 Gy to the SCRC followed by standardized chemotherapy. A phase III multicenter trial with patient-specific dosing is planned.

Phase 1 Trial of Gefitinib Plus Sirolimus in Adults with Recurrent Malignant Glioma

PURPOSE

To determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of gefitinib, a receptor tyrosine kinase inhibitor of the epidermal growth factor receptor, plus sirolimus, an inhibitor of the mammalian target of rapamycin, among patients with recurrent malignant glioma.

PATIENTS AND METHODS

Gefitinib and sirolimus were administered on a continuous daily dosing schedule at dose levels that were escalated in successive cohorts of malignant glioma patients at any recurrence who were stratified based on concurrent use of CYP3A-inducing anticonvulsants [enzyme-inducing antiepileptic drugs, (EIAED)]. Pharmacokinetic and archival tumor biomarker data were also assessed.

RESULTS

Thirty-four patients with progressive disease after prior radiation therapy and chemotherapy were enrolled, including 29 (85%) with glioblastoma multiforme and 5 (15%) with anaplastic glioma. The MTD was 500 mg of gefitinib plus 5 mg of sirolimus for patients not on EIAEDs and 1,000 mg of gefitinib plus 10 mg of sirolimus for patients on EIAEDs. DLTs included mucositis, diarrhea, rash, thrombocytopenia, and hypertriglyceridemia. Gefitinib exposure was not affected by sirolimus administration but was significantly lowered by concurrent EIAED use. Two patients (6%) achieved a partial radiographic response, and 13 patients (38%) achieved stable disease.

CONCLUSION

We show that gefitinib plus sirolimus can be safely coadministered on a continuous, daily dosing schedule, and established the recommended dose level of these agents in combination for future phase 2 clinical trials.

Phase II study of imatinib mesylate plus hydroxyurea in adults with recurrent glioblastoma multiforme

PURPOSE

We performed a phase II study to evaluate the combination of imatinib mesylate, an adenosine triphosphate mimetic, tyrosine kinase inhibitor, plus hydroxyurea, a ribonucleotide reductase inhibitor, in patients with recurrent glioblastoma multiforme (GBM).

PATIENTS AND METHODS

Patients with GBM at any recurrence received imatinib mesylate plus hydroxyurea (500 mg twice a day) orally on a continuous, daily schedule. The imatinib mesylate dose was 500 mg twice a day for patients on enzyme-inducing antiepileptic drugs (EIAEDs) and 400 mg once a day for those not on EIAEDs. Assessments were performed every 28 days. The primary end point was 6-month progression-free survival (PFS).

RESULTS

Thirty-three patients enrolled with progressive disease after prior radiotherapy and at least temozolomide-based chemotherapy. With a median follow-up of 58 weeks, 27% of patients were progression-free at 6 months, and the median PFS was 14.4 weeks. Three patients (9%) achieved radiographic response, and 14 (42%) achieved stable disease. Cox regression analysis identified concurrent EIAED use and no more than one prior progression as independent positive prognostic factors of PFS. The most common toxicities included grade 3 neutropenia (16%), thrombocytopenia (6%), and edema (6%). There were no grade 4 or 5 events. Concurrent EIAED use lowered imatinib mesylate exposure. Imatinib mesylate clearance was decreased at day 28 compared with day 1 in all patients, suggesting an effect of hydroxyurea.

CONCLUSION

Imatinib mesylate plus hydroxyurea is well tolerated and associated with durable antitumor activity in some patients with recurrent GBM.

Treatment of Neoplastic Meningitis With Intrathecal 9-Nitro-camptothecin

The topoisomerase I inhibitor, 9-nitro-camptothecin (9NC), is highly tumoricidal against glioblastoma multiforme (GBM) in vitro. However, systemic administration of 9NC has not shown the expected efficacy in clinical trials. This failure may be due to the rapid hydrolysis of 9NC in plasma from the active form to the inactive and myelosuppressive form in the presence of human albumin at physiologic pH. Concurrent treatment with anticonvulsants and dexamethasone, drugs indispensable for the supportive therapy of patients with GBM, has also been shown to decrease plasma concentrations of these drugs. Intrathecal drug delivery circumvents the blood-brain barrier and minimizes systemic toxicity. Intrathecal delivery of 9NC may also have the more specific advantage of significantly reducing the hydrolysis of 9NC that occurs after systemic delivery due to the more favorable pH and reduced albumin content in cerebrospinal fluid. The present study evaluated the toxicity and efficacy of intrathecal delivery of 9NC in an athymic rat model of neoplastic meningitis. Toxicity tests showed that 0.3 micromol (5000 microM), 0.03 micromol (500 microM), 0.003 micromol (50 microM), or 0.0003 micromol (5 microM) of 9NC administered intrathecally to the athymic rats caused no evidence of clinical or histological toxicity. Intrathecal administration of 0.3 micromol (5000 microM) of 9NC twice a week for three doses to athymic rats with neoplastic meningitis induced by the GBM cell line, U87MGDeltaEGFR, resulted in a 26% increase of median survival compared to the control group (p < 0.005). These results suggest that intrathecal treatment with 9NC may be useful for patients with GBM neoplastic meningitis.

A phase II window trial of procarbazine and topotecan in children with high-grade glioma: a report from the children’s oncology group

The role of chemotherapy in the treatment of high-grade gliomas in children is unclear. Early reports were suggestive of improved outcome in children with high-grade glioma with the addition of chemotherapy after surgery and radiation therapy. Subsequent studies did not show similar favorable contribution of chemotherapy to the outcome of these children. Further efforts to identify active chemotherapy agents in children include use of agents that have shown efficacy in adult patients with high-grade glioma and agents that have shown promise in mice bearing human xenografts of brain tumors. A Pediatric Oncology Group (POG 9431) trial tested the activity of two such agents, procarbazine and topotecan in newly diagnosed patients with high-grade glioma who had measurable disease after diagnostic surgery. Neither agent showed efficacy within the confines of the statistical design of the study. This study showed that children with high-grade glioma have an innate resistance to alkylating agents based on mismatch repair deficiency and high levels of alkyguanine transferase (AGT). Future trials should consider strategies to overcome the resistance mechanisms in children with high-grade glioma.

ZD6474, a Novel Tyrosine Kinase Inhibitor of Vascular Endothelial Growth Factor Receptor and Epidermal Growth Factor Receptor, Inhibits Tumor Growth of Multiple Nervous System Tumors

PURPOSE

Primary central nervous system (CNS) tumors represent a diverse group of tumor types with heterogeneous molecular mechanisms that underlie their formation and maintenance. CNS tumors depend on angiogenesis and often display increased activity of ErbB-associated pathways. Current nonspecific therapies frequently have poor efficacy in many of these tumor types, so there is a pressing need for the development of novel targeted therapies.

EXPERIMENTAL DESIGN

ZD6474 is a novel, orally available low molecular weight inhibitor of the kinase activities associated with vascular endothelial growth factor receptor-2 and epidermal growth factor receptor. We hypothesized that ZD6474 may provide benefit in the treatment of several CNS tumor types.

RESULTS

In mice bearing established s.c. tumor xenografts of CNS tumors (malignant glioma and ependymoma) or rhabdomyosarcoma, a limited course of ZD6474 treatment produced significant tumor growth delays and a high rate of partial tumor regression in most models examined. Mice with i.c. malignant glioma xenografts treated with ZD6474 experienced a significant prolongation of survival. Tumors from mice treated with ZD6474 displayed a lower proliferative index and disrupted tumor vascularity. Notably, some of these models are insensitive to low molecular weight kinase inhibitors targeting only vascular endothelial growth factor receptor-2 or epidermal growth factor receptor functions, suggesting that the combined disruption of both epidermal growth factor receptor and vascular endothelial growth factor receptor-2 activities may significantly increase tumor control.

CONCLUSIONS

In conclusion, ZD6474 shows significant activity against xenograft models of several primary human CNS tumor types. Consideration for clinical development in this disease setting seems warranted.

Survival analysis of presumptive prognostic markers among oligodendrogliomas

BACKGROUND

Allelic losses of 1p and 19q arms correlate with the oligodendroglial phenotype as well as with sensitivity to radiotherapy and chemotherapy. Furthermore, the DNA repair gene, methylguanine methyltransferase (MGMT), is diminished in 80% of oligodendroglial tumors and represents a possible mechanism for this therapeutic sensitivity. However, the authors questioned the relevance of genetic testing and measuring MGMT levels in tumors that were diagnostic of oligodendroglioma.

METHODS

The authors performed a retrospective analysis of 1p, 19q, 9p21, TP53, and MGMT status in 46 patients with oligodendrogliomas to address any relations that may exist among these markers with regard to progression-free survival (PFS) and total survival. Methodologies included comparative genomic hybridization; loss of heterozygosity (LOH) on 1p, 19q, and 9p21; TP53 mutational analysis; and immunohistochemistry for MGMT.

RESULTS

The authors found that survival among patients with light microscopically diagnosed oligodendroglial tumors demonstrating LOH of 1p and 19q trended toward statistical significance (P = 0.102 and P = 0.058, respectively). 9p21 LOH was significant as a predictor of PFS only among anaplastic oligodendrogliomas in this cohort (P = 0.033). TP53 mutation was found to be significantly predictive of a shorter survival (P = 0.027) among all patients and exhibited a strong trend toward a shorter PFS (P = 0.060). Low-level MGMT labeling index (LI) (< 20%) was noted in 86% of all oligodendroglial tumors. MGMT LI was not found to correlate with an improved PFS or total survival in this cohort, recognizing that median survival was not reached after a median follow-up of 104 months.

CONCLUSIONS

9p21 and TP53 mutational status assisted in developing a stricter subclassification of these tumors with prognostic significance. MGMT levels were decreased in a majority of oligodendrogliomas.

Phase I Trial of Temozolomide PlusO6-Benzylguanine for Patients With Recurrent or Progressive Malignant Glioma

Purpose

We conducted a two-phase clinical trial in patients with progressive malignant glioma (MG). The first phase of this trial was designed to determine the dose of O6-BG effective in producing complete depletion of tumor AGT activity for 48 hours. The second phase of the trial was designed to define the maximum tolerated dose (MTD) of a single dose of temozolomide when combined with O6-BG. In addition, plasma concentrations of O6-BG and O6-benzyl-8-oxoguanine were evaluated after O6-BG.

Patients and Methods

For our first phase of the clinical trial, patients were scheduled to undergo craniotomy for AGT determination after receiving a 1-hour O6-BG infusion at 120 mg/m2followed by a continuous infusion at an initial dose of 30 mg/m2/d for 48 hours. The dose of the continuous infusion of O6-BG escalated until tumor AGT was depleted. Once the O6-BG dose was established a separate group of patients was enrolled in the second phase of clinical trial, in which temozolomide, administered as a single dose at the end of the 1-hour O6-BG infusion, was escalated until the MTD was determined.

Results

The O6-BG dose found to be effective in depleting tumor AGT activity at 48 hours was an IV bolus of 120 mg/m2over 1 hour followed by a continuous infusion of 30 mg/m2/d for 48 hours. On enrolling 38 patients in six dose levels of temozolomide, the MTD was established at 472 mg/m2with dose-limiting toxicities limited to myelosuppression.

Conclusion

This study provides the foundation for a phase II trial of O6-BG plus temozolomide in temozolomide-resistant MG.

Dosimetry and radiographic analysis of 131I-labeled anti-tenascin 81C6 murine monoclonal antibody in newly diagnosed patients with malignant gliomas: a phase II study

The objective was to perform dosimetry and evaluate dose-response relationships in newly diagnosed patients with malignant brain tumors treated with direct injections of (131)I-labeled anti-tenascin murine 81C6 monoclonal antibody (mAb) into surgically created resection cavities (SCRCs) followed by conventional external-beam radiotherapy and chemotherapy.

METHODS

Absorbed doses to the 2-cm-thick shell, measured from the margins of the resection cavity interface, were estimated for 33 patients with primary brain tumors. MRI/SPECT registrations were used to assess the distribution of the radiolabeled mAb in brain parenchyma. Results from biopsies obtained from 15 patients were classified as tumor, radionecrosis, or tumor and radionecrosis, and these were correlated with absorbed dose and dose rate. Also, MRI/PET registrations were used to assess radiographic progression among patients.

RESULTS

This therapeutic strategy yielded a median survival of 86 and 79 wk for all patients and glioblastoma multiforme (GBM) patients, respectively. The average SCRC residence time of (131)I-mu81C6 mAb was 76 h (range, 34-169 h). The average absorbed dose to the 2-cm cavity margins was 48 Gy (range, 25-116 Gy) for all patients and 51 Gy (range, 27-116 Gy) for GBM patients. In MRI/SPECT registrations, we observed a preferential distribution of (131)I-mu81C6 mAb through regions of vasogenic edema. An analysis of the relationship between the absorbed dose and dose rate and the first biopsy results yielded a most favorable absorbed dose of 44 Gy. A correlation between decreased survival and irreversible neurotoxicity was noted. A comparative analysis, in terms of median survival, was performed with previous brachytherapy clinical studies, which showed a proportional relationship between the average boost absorbed dose and the median survival.

CONCLUSION

This study shows that (131)I-mu81C6 mAb increases the median survival of GBM patients. An optimal absorbed dose of 44 Gy to the 2-cm cavity margins is suggested to reduce the incidence of neurologic toxicity. Further clinical studies are warranted to determine the effectiveness of (131)I-mu81C6 mAb based on a target dose of 44 Gy rather than a fixed administered activity.

Gene Expression Profiling and Genetic Markers in Glioblastoma Survival

Despite the strikingly grave prognosis for older patients with glioblastomas, significant variability in patient outcome is experienced. To explore the potential for developing improved prognostic capabilities based on the elucidation of potential biological relationships, we did analyses of genes commonly mutated, amplified, or deleted in glioblastomas and DNA microarray gene expression data from tumors of glioblastoma patients of age >50 for whom survival is known. No prognostic significance was associated with genetic changes in epidermal growth factor receptor (amplified in 17 of 41 patients), TP53 (mutated in 11 of 41 patients), p16INK4A (deleted in 15 of 33 patients), or phosphatase and tensin homologue (mutated in 15 of 41 patients). Statistical analysis of the gene expression data in connection with survival involved exploration of regression models on small subsets of genes, based on computational search over multiple regression models with cross-validation to assess predictive validity. The analysis generated a set of regression models that, when weighted and combined according to posterior probabilities implied by the statistical analysis, identify patterns in expression of a small subset of genes that are associated with survival and have value in assessing survival risks. The dominant genes across such multiple regression models involve three key genes-SPARC (Osteonectin), Doublecortex, and Semaphorin3B-which play key roles in cellular migration processes. Additional analysis, based on statistical graphical association models constructed using similar computational analysis methods, reveals other genes which support the view that multiple mediators of tumor invasion may be important prognostic factor in glioblastomas in older patients.

Accreditation Council for Graduate Medical Education (ACGME) Competencies in Neuropathology Training

The Accreditation Council for Graduate Medical Education (ACGME) has defined 6 core competencies for all physicians: patient care; medical knowledge; practice-based learning and improvement; interpersonal and communication skills; professionalism; and systems-based practice. However, the specific wording of the descriptions often assumes that the physician is a clinician rather than a pathologist. Therefore, the American Association of Neuropathologists, Inc. asked its Professional Affairs Committee to examine the core competencies and determine how they relate to training in neuropathology. The Committee's report is presented here in 6 sections, corresponding to the 6 competencies. In each section, the ACGME definition of that particular competency is either quoted directly or, more often, modified slightly to clarify how the competency applies to neuropathology. Each of the defined competencies is then followed by possible assessment tools, selected from those recommended in the ACGME's "toolbox." Specific suggestions are given for designing tools that apply to neuropathology. Many of the suggested activities and documentation methods can be combined into efficient, carefully formulated training/evaluation exercises. Different tools may be more applicable in some training programs.

Sustained radiographic and clinical response in patient with bifrontal recurrent glioblastoma multiforme with intracerebral infusion of the recombinant targeted toxin TP-38: case study

Glioblastoma multiforme remains refractory to conventional therapy, and novel therapeutic modalities are desperately needed. TP-38 is a recombinant chimeric protein containing a genetically engineered form of the cytotoxic Pseudomonas exotoxin fused to transforming growth factor (TGF)-alpha. TGF-alpha binds with high affinity to the epidermal growth factor receptor, which is uniformly overexpressed in malignant gliomas, often because of gene amplification. Prior to therapy with TP-38, the patient described here was completely refractory to multiple other therapies, with radiographic and pathologic evidence of tumor progression. After therapy, she improved clinically, was weaned off steroids and anti-convulsants, and experienced a progressive decrease in enhancing tumor volume. Despite multiple prior recurrences, she has not progressed for >43 months after TP-38 therapy. Small remaining areas of enhancement demonstrate no evidence of tumor histologically and are hypometabolic on positron emission tomography. This report describes a dramatic and sustained clinical and radiographic response in a patient with a bifrontal glioblastoma multiforme treated with intratumoral infusion of a novel targeted toxin, TP-38.

Identification of OTX2 as a Medulloblastoma Oncogene Whose Product can be Targeted by All-Trans Retinoic Acid

Through digital karyotyping of permanent medulloblastoma cell lines, we found that the homeobox gene OTX2 was amplified more than 10-fold in three cell lines. Gene expression analyses showed that OTX2 transcripts were present at high levels in 14 of 15 (93%) medulloblastomas with anaplastic histopathologic features. Knockdown of OTX2 expression by siRNAs inhibited medulloblastoma cell growth in vitro, whereas pharmacologic doses of all-trans retinoic acid repressed OTX2 expression and induced apoptosis only in medulloblastoma cell lines that expressed OTX2. These observations suggest that OTX2 is essential for the pathogenesis of anaplastic medulloblastomas and that these tumors may be amenable to therapy with all-trans-retinoic acid.

Identification of OTX2 as a medulloblastoma oncogene whose product can be targeted by all-trans retinoic acid

Through digital karyotyping of permanent medulloblastoma cell lines, we found that the homeobox gene OTX2 was amplified more than 10-fold in three cell lines. Gene expression analyses showed that OTX2 transcripts were present at high levels in 14 of 15 (93%) medulloblastomas with anaplastic histopathologic features. Knockdown of OTX2 expression by siRNAs inhibited medulloblastoma cell growth in vitro, whereas pharmacologic doses of all-trans retinoic acid repressed OTX2 expression and induced apoptosis only in medulloblastoma cell lines that expressed OTX2. These observations suggest that OTX2 is essential for the pathogenesis of anaplastic medulloblastomas and that these tumors may be amenable to therapy with all-trans-retinoic acid.

Comparative genomic hybridization analysis of astrocytomas: prognostic and diagnostic implications

Astrocytoma is comprised of a group of common intracranial neoplasms that are classified into four grades based on the World Health Organization histological criteria and patient survival. To date, histological grade, patient age, and clinical performance, as reflected in the Karnofsky score, are the most reliable prognostic predictors. Recently, there has been a significant effort to identify additional prognostic markers using objective molecular genetic techniques. We believe that the identification of such markers will characterize new chromosomal loci important in astrocytoma progression and aid clinical diagnosis and prognosis. To this end, our laboratory used comparative genomic hybridization to identify DNA sequence copy number changes in 102 astrocytomas. Novel losses of 19p loci were detected in low-grade pilocytic astrocytomas and losses of loci on 9p, 10, and 22 along with gains on 7, 19, and 20 were detected in a significant proportion of high-grade astrocytomas. The Cox proportional hazards statistical modeling showed that the presence of +7q and -10q comparative genomic hybridization alterations significantly increased a patient's risk of dying, independent of histological grade. This investigation demonstrates the efficacy of comparative genomic hybridization for identifying tumor suppressor and oncogene loci in different astrocytic grades. The cumulative effect of these loci is an important consideration in their diagnostic and prognostic implications.

Combination therapy of inhibitors of epidermal growth factor receptor/vascular endothelial growth factor receptor 2 (AEE788) and the mammalian target of rapamycin (RAD001) offers improved glioblastoma tumor growth inhibition

Malignant gliomas are highly lethal tumors that display striking genetic heterogeneity. Novel therapies that inhibit a single molecular target may slow tumor progression, but tumors are likely not dependent on a signal transduction pathway. Rather, malignant gliomas exhibit sustained mitogenesis and cell growth mediated in part through the effects of receptor tyrosine kinases and the mammalian target of rapamycin (mTOR). AEE788 is a novel orally active tyrosine kinase inhibitor that decreases the kinase activity associated with the epidermal growth factor receptor and, at higher concentrations, the vascular endothelial growth factor receptor 2 (kinase domain region). RAD001 (everolimus) is an orally available mTOR inhibitor structurally related to rapamycin. We hypothesized that combined inhibition of upstream epidermal growth factor receptor and kinase domain region receptors with AEE788 and inhibition of the downstream mTOR pathway with RAD001 would result in increased efficacy against gliomas compared with single-agent therapy. In vitro experiments showed that the combination of AEE788 and RAD001 resulted in increased rates of cell cycle arrest and apoptosis and reduced proliferation more than either agent alone. Combined AEE788 and RAD001 given orally to athymic mice bearing established human malignant glioma tumor xenografts resulted in greater tumor growth inhibition and greater increases in median survival than monotherapy. These studies suggest that simultaneous inhibition of growth factor receptor and mTOR pathways offer increased benefit in glioma therapy.

Combination therapy of inhibitors of epidermal growth factor receptor/vascular endothelial growth factor receptor 2 (AEE788) and the mammalian target of rapamycin (RAD001) offers improved glioblastoma tumor growth inhibition

Malignant gliomas are highly lethal tumors that display striking genetic heterogeneity. Novel therapies that inhibit a single molecular target may slow tumor progression, but tumors are likely not dependent on a signal transduction pathway. Rather, malignant gliomas exhibit sustained mitogenesis and cell growth mediated in part through the effects of receptor tyrosine kinases and the mammalian target of rapamycin (mTOR). AEE788 is a novel orally active tyrosine kinase inhibitor that decreases the kinase activity associated with the epidermal growth factor receptor and, at higher concentrations, the vascular endothelial growth factor receptor 2 (kinase domain region). RAD001 (everolimus) is an orally available mTOR inhibitor structurally related to rapamycin. We hypothesized that combined inhibition of upstream epidermal growth factor receptor and kinase domain region receptors with AEE788 and inhibition of the downstream mTOR pathway with RAD001 would result in increased efficacy against gliomas compared with single-agent therapy. In vitro experiments showed that the combination of AEE788 and RAD001 resulted in increased rates of cell cycle arrest and apoptosis and reduced proliferation more than either agent alone. Combined AEE788 and RAD001 given orally to athymic mice bearing established human malignant glioma tumor xenografts resulted in greater tumor growth inhibition and greater increases in median survival than monotherapy. These studies suggest that simultaneous inhibition of growth factor receptor and mTOR pathways offer increased benefit in glioma therapy.

Meningioma with eosinophilic granular inclusions

Rare meningiomas have been described that contain eosinophilic inclusions that have a granular or granulofilamentous ultrastructure. We describe a 66-year-old woman who developed a planum sphenoidale meningioma. Histologically, the tumor was composed of meningothelial cells arranged in fascicles and whorls, typical of a well-differentiated meningioma. Many tumor cells contained round intracytoplasmic eosinophilic inclusions that were periodic acid Schiff-negative and red on Masson trichrome. The inclusions were immunopositive for vimentin, and were immunonegative for epithelial membrane antigen, smooth muscle actin, desmin and type IV collagen. Ultrastructural examination showed the inclusions were composed of round to oval, well-demarcated, non-membrane-bound, osmiophilic granular material. The inclusions within this tumor had histochemical, immunohistochemical and ultrastructural properties not described in other reported meningiomas with eosinophilic granular or granulofilamentous inclusions.

Mutations of PIK3CA in anaplastic oligodendrogliomas, high-grade astrocytomas, and medulloblastomas

The phosphatidylinositol 3'-kinase pathway is activated in multiple advanced cancers, including glioblastomas, through inactivation of the PTEN tumor suppressor gene. Recently, mutations in PIK3CA, a member of the family of phosphatidylinositol 3'-kinase catalytic subunits, were identified in a significant fraction (25-30%) of colorectal cancers, gastric cancers, and glioblastomas and in a smaller fraction of breast and lung cancers. These mutations were found to cluster into two major "hot spots" located in the helical and catalytic domains. To determine whether PIK3CA is genetically altered in brain tumors, we performed a large-scale mutational analysis of the helical and catalytic domains. A total of 13 mutations of PIK3CA within these specific domains were identified in anaplastic oligodendrogliomas, anaplastic astrocytomas, glioblastoma multiforme, and medulloblastomas, whereas no mutations were identified in ependymomas or low-grade astrocytomas. These observations implicate PIK3CA as an oncogene in a wider spectrum of adult and pediatric brain tumors and suggest that PIK3CA may be a useful diagnostic marker or a therapeutic target in these cancers.

The double-stranded RNA-activated protein kinase mediates viral-induced encephalitis

The double-stranded (ds) RNA-activated protein kinase (PKR) plays an important role in control of viral infections and cell growth. We have studied the role of PKR in viral infection in mice that are defective in the PKR signaling pathway. Transgenic mice were derived that constitutively express a trans-dominant-negative kinase-defective mutant PKR under control of the beta-actin promoter. The trans-dominant-negative PKR mutant expressing transgenic mice do not have a detectable phenotype, similar to observations with PKR knock-out mice. The requirement for PKR in viral pathogenesis was studied by intracerebral infection of mice with a mouse-adapted poliovirus. Histopathological analysis revealed diffuse encephalomyelitis with severe inflammatory lesions throughout the central nervous system (CNS) in infected wild-type mice. In contrast, histopathological evaluation of virus-injected trans-dominant-negative PKR transgenic mice as well as PKR knock-out mice yielded no signs of tissue damage associated with inflammatory host responses. However, the virus did replicate in both models of PKR-deficient mice at a level equal to that observed in wild-type infected mice. Although the results indicate a clear difference in susceptibility to poliovirus-induced encephalitis, this difference manifests clinically as a slight delay in fatal neuropathy in trans-dominant-negative PKR transgenic and PKR knock-out animals. Our observations support the finding that viral-induced PKR activation may play a significant role in pathogenesis by mediating the host response to viral CNS infection. They support PKR to be an effective target to control tissue damage due to deleterious host responses to viral infection.

Progress report of a Phase I study of the intracerebral microinfusion of a recombinant chimeric protein composed of transforming growth factor (TGF)-alpha and a mutated form of the Pseudomonas exotoxin termed PE-38 (TP-38) for the treatment of malignant brain tumors

TP-38 is a recombinant chimeric targeted toxin composed of the EGFR binding ligand TGF-alpha and a genetically engineered form of the Pseudomonas exotoxin, PE-38. After in vitro and in vivo animal studies that showed specific activity and defined the maximum tolerated dose (MTD), we investigated this agent in a Phase I trial. The primary objective of this study was to define the MTD and dose limiting toxicity of TP-38 delivered by convection-enhanced delivery in patients with recurrent malignant brain tumors. Twenty patients were enrolled in the study and doses were escalated from 25 ng/mL to 100 with a 40 mL infusion volume delivered by two catheters. One patient developed Grade IV fatigue at the 100 ng/mL dose, but the MTD has not been established. The overall median survival after TP-38 for all patients was 23 weeks whereas for those without radiographic evidence of residual disease at the time of therapy, the median survival was 31.9 weeks. Overall, 3 of 15 patients, with residual disease at the time of therapy, have demonstrated radiographic responses and one patient with a complete response and has survived greater than 83 weeks.

The pathology of extracranial scalp and skull masses in young children

OBJECTIVE

Extracranial subcutaneous masses involving the scalp and/or skull in young children are uncommon lesions that get excised by the neurosurgeon. Although the most common reported lesion is the dermoid cyst, our experience suggests that the spectrum of pathology in these lesions can present diagnostic challenges to the pathologist.

MATERIAL

We reviewed 30 consecutive extracranial masses from 29 patients between July 1998 and June 2003.

METHOD

Hematoxylin and eosin-stained sections were reviewed in all cases, and immunohistochemistry was performed in select cases.

RESULTS

Twenty-three were within the scalp, 5 involved the scalp and skull and 2 were within the limits of the inner and outer tables of the skull. There were 8 dermoid cysts, 2 epidermoid cysts, 6 post-traumatic lesions including 3 calcified cephalhematomas and 3 pseudocysts, 5 vascular lesions including 3 capillary hemangiomas, 1 venous angioma and 1 lymphangioma, 2 cases of cranial fasciitis and 1 case each of benign teratoma, deep granuloma annulare, benign fibrous histiocytoma, congenital melanocytic nevus, hamartoma with ectopic meningothelial elements, cutaneous hyalinised ectopic meningioma and a meningocele with a fibrohistiocytic reaction. No lesions have recurred or exhibited malignant features.

CONCLUSIONS

Surgical pathologists and neuropathologists should be aware that the differential diagnosis of "lumps and bumps on babie's heads" is quite varied and can be histologically challenging.

Phase II Trial of Gefitinib in Recurrent Glioblastoma

Purpose

To evaluate the efficacy and tolerability of gefitinib (ZD1839, Iressa; AstraZeneca, Wilmington, DE), a novel epidermal growth factor receptor tyrosine kinase inhibitor, in patients with recurrent glioblastoma.

Patients and Methods

This was an open-label, single-center phase II trial. Fifty-seven patients with first recurrence of a glioblastoma who were previously treated with surgical resection, radiation, and usually chemotherapy underwent an open biopsy or resection at evaluation for confirmation of tumor recurrence. Each patient initially received 500 mg of gefitinib orally once daily; dose escalation to 750 mg then 1,000 mg, if a patient received enzyme-inducing antiepileptic drugs or dexamethasone, was allowed within each patient.

Results

Although no objective tumor responses were seen among the 53 assessable patients, only 21% of patients (11 of 53 patients) had measurable disease at treatment initiation. Seventeen percent of patients (nine of 53 patients) underwent at least six 4-week cycles, and the 6-month event-free survival (EFS) was 13% (seven of 53 patients). The median EFS time was 8.1 weeks, and the median overall survival (OS) time from treatment initiation was 39.4 weeks. Adverse events were generally mild (grade 1 or 2) and consisted mainly of skin reactions and diarrhea. Drug-related toxicities were more frequent at higher doses. Withdrawal caused by drug-related adverse events occurred in 6% of patients (three of 53 patients). Although the presence of diarrhea positively predicted favorable OS from treatment initiation, epidermal growth factor receptor expression did not correlate with either EFS or OS.

Conclusion

Gefitinib is well tolerated and has activity in patients with recurrent glioblastoma. Further study of this agent at higher doses is warranted.

Efficacy of intracerebral microinfusion of trastuzumab in an athymic rat model of intracerebral metastatic breast cancer

PURPOSE

The monoclonal antibody (MAb) trastuzumab (Herceptin) effectively treats HER2-overexpressing extracerebral breast neoplasms. Delivery of such macromolecule therapeutic agents to intracerebral metastases, however, is limited by the tight junctions characteristic of the cerebral vasculature. Direct intracerebral microinfusion (ICM) is a technique that bypasses this blood-brain barrier and allows for a greater delivery of drugs directly into intracerebral tumors.

EXPERIMENTAL DESIGN

A human breast cancer cell line transfected to overexpress HER2, MCF-7/HER2-18, was transplanted into the cerebrum of athymic rats. Saline, trastuzumab, or an isotype-matched control MAb was delivered systemically or by ICM to assess toxicity and efficacy.

RESULTS

No clinical or histological toxicity related to trastuzumab was evident under any of the conditions studied. Delivery of trastuzumab (2 mg/kg) i.p. led to a median survival of 26.5 days, whereas treatment with trastuzumab (2 mg/kg) by ICM increased the median survival by 96% to 52 days, with two of nine rats surviving >120 days (P = 0.009). Treatment with an isotype-matched control MAb (16 mg/kg) resulted in a median survival of 21 days, which did not differ significantly from the survival of rats treated by ICM with saline (16 days; P = 0.42). Treatment by ICM with trastuzumab (16 mg/kg) led to a median survival of 45 days, with 2 of 10 rats surviving >120 days. These results represent 181% and 114% increases in median survival over the saline and MAb controls, respectively (P < 0.001).

CONCLUSION

ICM of trastuzumab is safe and superior to systemic delivery as therapy for HER2-overexpressing intracerebral neoplasms in an athymic rat model.

Is the long-term survival of patients with intracranial glioblastoma multiforme overstated?

BACKGROUND

The 5-year survival rate for intracranial glioblastoma multiforme (GBM) has remained at 4-5% for the last 30 years, in spite of multiple randomized prospective trials. The authors hypothesized, based on the literature, that even this remarkably poor survival rate is an overstatement. They investigated this hypothesis using the the Duke University Medical Center Tumor Registry.

METHODS

The authors reviewed all patients with the diagnosis of intracranial GBM recorded in the Duke University Medical Center Tumor Registry from the registry's inception in 1976 through 1996. This search identified a population of patients with a minimum of 5 years of follow-up. Each of the long-term survivors was assigned a code number for clinical information. The pathology slides were provided to a neuropathologist in a coded fashion so that the patients could not be identified. The neuropathologist reviewed the slides to analyze the presence or absence of nine histologic factors. A match technique was used to identify a control population of patients with GBM who were not 5-year survivors and were all deceased. The control population was compared with the study population to ascertain if there are histologic correlates associated with long-term survivorship.

RESULTS

The authors identified 766 patients recorded by the tumor registry as having an intracranial GBM with a minimum of 5 years of follow up. Of the total population, 32 patients initially appeared to be 5-year survivors (4%). Upon review of the medical records for these 32 patients, however, the authors found only 17 patients who were truly 5-year survivors. The most common reason for miscoding was the presence of a low-grade astrocytoma that subsequently dedifferentiated into GBM. The 17 long-term survivors included 11 males and 6 females. Their mean age at diagnosis was 40.2 years. Therapy consisted of a macroscopic total resection in 4 patients (22%), a biopsy in 1 patient (6%), a subtotal resection in 10 patients (56%), and unknown extent of resection in 2 patients (11%). All patients received partial brain irradiation (mean dose, 62.6 Gy) and chemotherapy. Thirteen different single-agent or combination chemotherapy programs were used. Two patients also received I-131 monoclonal antibody therapy. Analysis of the nine histopathologic factors studied showed that intermediate fibrillary elements were more common and small anaplastic elements were less common in the long-term survivors than in the control population.

CONCLUSIONS

Survival data on intracranial GBM, based on tumor registry data, should be interpreted cautiously. Reliable conclusions can only be drawn when such data are supplemented with clinical information and the histopathology is reviewed carefully. The group of long-term survivors in the current study were younger than the typical GBM population. Conventionally treated patients with GBM, chosen from an unselected population from a tumor registry, have a smaller chance of long-term survival than is generally believed.

High-dose chemotherapy with autologous stem-cell rescue in children and adults with newly diagnosed pineoblastomas

PURPOSE

We evaluated the usefulness of a treatment regimen that included high-dose chemotherapy (HDC) with autologous stem-cell rescue (ASCR) in patients with newly diagnosed pineoblastoma (PBL).

PATIENTS AND METHODS

Twelve patients with PBL were initially treated with surgery and induction chemotherapy. All but two patients underwent radiotherapy. Subsequently, all patients received HDC using cyclophosphamide (CTX) + melphalan (MEL) or busulfan (Bu) + MEL regimens and ASCR.

RESULTS

A total of six children and six adults with median ages of 4.2 (range, 0.3 to 19.8 years) and 23 years (range, 23 to 43.7 years), respectively, were treated according to this strategy. Four patients had metastatic disease confined to the neuraxis. Five of 12 patients (42%) had a complete tumor resection at diagnosis. Ten patients received radiotherapy at median doses of 36.0 and 59.4 Gy to the neuraxis and pineal region, respectively. Eleven patients received HDC with CTX + MEL, and one patient received BU + MEL followed by ASCR. Nine patients are alive with no evidence of disease recurrence at a median of 62 months from diagnosis (range, 28 to 125 months), including three patients with metastatic disease and two infants who did not receive any radiotherapy. Three patients have died of progressive disease at 19, 32, and 37 months from diagnosis, respectively. The actuarial 4-year progression-free and overall survivals are 69% (95% confidence interval [CI], 39% to 99%) and 71% (95% CI, 43% to 99%), respectively.

CONCLUSION

The use of HDC in addition to radiotherapy seems to be an effective treatment for patients with newly diagnosed pineoblastoma.

Glioneuronal tumors of the central nervous system

Advances in the immunohistochemical detection of neuron-specific and neuronal-associated antigens have resulted in the discovery of neuronal elements in certain primary human brain tumors. The results have been not only to expand what neuropathologists commonly recognize as gangliogliomas, including the tumors now known as glioneurocytic tumor with neuropil rosettes and papillary ganglioneuroma, but also to expand the spectrum of tumor types to now include tumors such as central neurocytoma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile ganglioglioma. These discoveries have helped us to better understand the biology of these tumors and to refine our classification of them. Distinctions among these tumors include sites of predilection, such as the temporal lobe with the dysembryoplastic neuroepithelial tumors, and a spectrum of clinical aggressiveness that spans indolent "quasi-hamartomatous" lesions, such as the dysembryoplastic neuroepithelial tumor, to high-grade, highly aggressive tumors, such as the supratentorial primitive neuroectodermal tumor (World Health Organization Grade IV). Many of these tumors also commonly exhibit a glial component, as determined by both their histologic appearance and their immunoreactivity for glial fibrillary acidic protein. This review covers these recently described lesions, including the desmoplastic infantile ganglioglioma, the dysembryoplastic neuroepithelial tumor, the papillary glioneuronal tumor, the glioneuronal tumor with neuropil rosettes, and the mixed glioblastoma-cerebral neuroblastoma (supratentorial primitive neuroectodermal tumor), as well as the known tumors, ganglioglioma, medulloepithelioma, and medulloblastoma. For pathologists confronted by this growing array of tumors and subtypes, it is appropriate to focus on them and understand the differential diagnosis to be considered when confronted by them.

Primary anaplastic large cell lymphoma of the central nervous system: prognostic effect of ALK-1 expression

Anaplastic large cell lymphoma (ALCL) rarely occurs in the central nervous system. Although defined by its composition of large, pleomorphic, CD30-positive lymphocytes, ALCL is heterogeneous. Most are T cell but some are null cell. Most but not all have a characteristic 2:5 translocation producing the fusion protein ALK-1, which is reliably detected by immunohistochemistry. In systemic ALCL, ALK-1 expression correlates with young patient age and a favorable prognosis. Herein we report four new cases of primary central nervous system ALCL from the Mayo Clinic and incorporate additional data from five previously published cases. ALK-1 expression was determined in all nine tumors. Patient age was 4-66 years (mean 29 years) with a bimodal distribution: 6 < or = 22 years, 3 > or = 50 years. Six were female. Tumors were mostly supratentorial, five were multifocal, and seven had involvement of dura or leptomeninges. Seven tumors were T cell, two were null cell, and five of nine were ALK-1 immunopositive. Total mortality was six of nine. Three patients, 4-18 years of age (mean 13 years), were alive at 4.8-6.1 years postdiagnosis; these tumors were all ALK positive. Five patients, 13-66 years of age (mean 43 years), died of tumor 4 days to 11 weeks postdiagnosis; four of five of these tumors were ALK negative. One 10-year-old child with an ALK-positive tumor died of sepsis, but in remission. Central nervous system ALCL is aggressive. Our study suggests that a better outcome may be associated with young age and ALK-1 positivity, prognostic parameters similar to systemic ALCL.

Phase II trial of temozolomide in patients with progressive low-grade glioma

PURPOSE

Temozolomide (Temodar; Schering-Plough Corp, Kenilworth, NJ) is an imidazole tetrazinone that undergoes chemical conversion to the active methylating agent 5-(3-methyltriazen-1yl)imidazole-4-carboximide under physiologic conditions. Previous studies have confirmed activity of Temodar in the treatment of progressive and newly diagnosed malignant gliomas. We have extended these results, and now we report results of a phase II trial of Temodar for patients with progressive, low-grade glioma.

PATIENTS AND METHODS

Temodar was administered orally once a day for five consecutive days (in a fasting state) at a starting dose of 200 mg/m(2)/d. Treatment cycles were repeated every 28 days following the first daily dose of Temodar. Response criteria used a combination of magnetic resonance imaging and physical examination to evaluate activity.

RESULTS

Forty-six patients with low-grade glioma have been treated to date. The objective response rate was 61% (24% complete response and 37% partial response), with an additional 35% of patients having stable disease. Median progression-free survival (PFS) was 22 months (95% confidence interval [CI], 15 to infinity months) with a 6-month PFS of 98% (95% CI, 94% to 100%) and a 12-month PFS of 76% (95% CI, 63% to 92%). Toxicity observed during the study was limited to only six patients. Three patients experienced grade 3 neutropenia, with a duration greater than 3 weeks in one patient, and two patients experienced grade 3 thrombocytopenia. One patient experienced > or = grade 4 toxicity, with intracerebral hemorrhage, neutropenia, thrombocytopenia, sepsis, and death.

CONCLUSION

Initial results indicate that Temodar may be active in the treatment of low-grade glioma, and thus, further evaluation of this agent in the treatment of these tumors is warranted.

Vascular targeted endoradiotherapy of tumors using alpha-particle-emitting compounds: theoretical analysis

PURPOSE

To establish the theoretical framework and study the feasibility of (211)At-labeled anti-tenascin chimeric 81C6 monoclonal antibody (mAb) as anti-vascular endoradiotherapy for the treatment of glioblastoma multiforme (GBM) tumors.

METHODS AND MATERIALS

The morphology of blood vessels from histologic images was analyzed and used along with reaction-diffusion equations to assess the activity concentration of (211)At-labeled chimeric 81C6 mAb in GBM tumor and normal-brain tissue. Alpha particle microdosimetry was then used to assess the survival probability and average absorbed dose for tumor and normal tissue endothelial cells (ECs) per unit vascular cumulated activity concentration q(source) (MBq-s g(-1)). In turn, these survival probabilities were used to assess the probability of failure Phi for a single vessel. Furthermore, using the vessel density, the specific tumor control probability per unit mass of tumor tissue (tcp) and the specific normal-tissue complication probability per unit mass of normal-brain tissue (ntcp) were estimated. The specific tumor control probability, tcp, was used to assess the overall tumor control probability (TCP) as a function of tumor mass.

RESULTS

The levels of (211)At-labeled ch81C6 mAb cumulated activity concentration in GBM tumor tissue were approximately five times higher than that in normal-brain tissue. Thus, the average absorbed dose to tumor ECs was higher than that of normal tissue ECs, and the survival probability for GBM ECs was lower than for normal-brain tissue ECs. Consequently, the resulting vessel-failure probability, Phi, for GBM tumor and for normal-brain tissue differ considerably, yielding a q(source) range between 10(3) and 10(4) MBq-s g(-1).

CONCLUSIONS

This theoretical analysis demonstrated that (211)At-labeled chimeric 81C6 is an effective anti-vascular therapy for the treatment of GBM tumors, yielding a tcp higher than 0.999 for vascular cumulated activity concentrations q(source) higher than 1 x 10(4) MBq-s g(-1), while yielding a low probability for normal-brain tissue damage.

Biphasic malignant meningioma: a comparative genomic hybridization study

To ascertain if a carcinoma-like component within a fibroblastic meningioma represented a metastatic carcinoma to a meningioma or malignant progression, we employed traditional immunohistochemical methods as well as comparative genomic hybridization (CGH) which compares chromosomal alterations. Vimentin and epithelial membrane antigen were strongly immunoreactive in both the fibroblastic and carcinoma-like components. The CGH profile in both components had similar chromosomal alterations, including losses of 1p, 14, 16p13-->p10 and 22. However, the CGH profiles from the fibroblastic component showed losses of 4p, 10q23-->q24 and 18, along with gains of 1q, 6q25-->qter and 13q32-->qter. The profile of the carcinoma-like component showed losses of chromosome 4, in addition to gains of 3p12-->q13.11, 5q14.3-->q23.2, 6pter-->p23, and 13q14.2-->qter. CGH analysis of a biphasic malignant meningioma confirmed that the disparate histologic components were genetically related and likely derivative from a common precursor, demonstrating genetic instability and clonal expansion. Furthermore, CGH showed that the histologically appearing low-grade fibroblastic component had not solely the characteristic alterations of a benign meningioma but had already progressed to an atypical meningioma.

Brain tumors in mice are susceptible to blockade of epidermal growth factor receptor (EGFR) with the oral, specific, EGFR-tyrosine kinase inhibitor ZD1839 (iressa)

Iressa (ZD1839) is a p.o.-active, selective, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that blocks signal transduction pathways implicated in cancer cell proliferation, survival, and host-dependent processes promoting cancer growth. EGFR is up-regulated in primary malignant tumors of the central nervous system (CNS) and in many systemic tumors that metastasize to the CNS. The purpose of our study was to evaluate the efficacy and toxicity of p.o.-administered ZD1839 for the treatment of established intracerebral (i.c.) tumors expressing EGFR or the tumorigenic mutated variant EGFRvIII, which is constitutively phosphorylated. Oral administration of ZD1839 at 50 or 100 mg/kg/day for 3 weeks in athymic mice with established i.c. A431 human epidermoid carcinoma expressing EGFR increased median survival by 88% (P = 0.009) and 105% (P < 0.001), respectively. Additionally, there was no evidence of systemic or CNS toxicity. However, ZD1839 failed to inhibit either s.c. or i.c. in vivo tumor growth when tumorigenicity was conferred by EGFRvIII. Western blotting revealed that treatment with ZD1839 virtually ablated phosphorylation of EGFR Tyr-1173 in A431 tumors. However, treatment of NR6M tumors with ZD1839 only partially decreased phosphorylation of EGFRvIII Tyr-1173 while up-regulating overall expression, suggesting that EGFRvIII may not be susceptible to the same molecular mechanisms of tyrosine kinase inhibition as EGFR. In conclusion, ZD1839 is active in a brain tumor model expressing EGFR, but not EGFRvIII, as EGFR mutations may lead to relative therapeutic resistance. On the basis of these observations, we believe that clinical trials of ZD1839 against brain tumors expressing EGFR are warranted, but that special consideration should be given to tumors that coexpress EGFRvIII.

Targeted delivery in primary and metastatic brain tumors: summary report of the seventh annual meeting of the Blood-Brain Barrier Disruption Consortium

The November 2000 NIH report of the Brain Tumor Progress Review Group identified delivering and targeting therapeutic agents as a priority in the treatment of malignant brain tumors. For this reason, the seventh annual Blood-Brain Barrier Disruption Consortium meeting, partially funded by an NIH R13 Grant, focused on recent advances in targeted delivery to the central nervous system, clinical trials for primary and metastatic brain tumors using enhanced chemotherapy delivery, and strategies to lessen the toxicities associated with dose intensive treatments, using thiols.

Molecular markers of prognosis in astrocytic tumors

BACKGROUND

Astrocytoma is a primary brain tumor that affects 20,000 Americans each year. To date, only age and histologic grade stand out as independent predictors of survival. There is now increased interest in the use of molecular markers as objective standards against which to establish diagnosis and grade.

METHODS

The study evaluated human glioma tumor suppressor genes and associated loci in fresh snap-frozen gliomas from 63 males and 37 females, with a median age of 42 years, including 19 low-grade astrocytomas. The tumor samples were selected so that about equal numbers of glioblastomas from younger and older patients were represented in the series. Methods for suppressor gene and genetic loci evaluation included loss of heterozygosity (LOH) analysis, multiplex polymerase chain reaction analysis, and gene sequencing.

RESULTS

Low-grade astrocytomas had the least number of molecular abnormalities. LOH on 9p and/or CDKN2A deletion occurred more often in glioblastomas (P < 0.001), LOH on 17p/TP53 mutations occurred more frequently in anaplastic astrocytomas (AAs; P = 0.112), and LOH on 10q/PTEN mutation frequency was similar in glioblastomas and AAs (P < 0.001). Poorer survival was associated significantly with the occurrence of either deletion of p16 (P = 0.031), LOH on 9p (P = 0.016), or LOH on 10q (P = 0.0007). The absence of LOH on 17p and the presence of PTEN mutation were associated marginally with survival. Even though TP53 mutations were more frequent among younger patients with glioblastoma, they had no statistically significant effect on survival after adjustment for age (P = 0.62). In all multivariate models, age and grade were the only significant predictors of survival or were nearly significant predictors of survival.

CONCLUSIONS

The results suggest that LOH on 9p and p16 deletions may prove to be objective standards for the diagnosis of patients with high-grade gliomas, although the absence of these abnormalities is nonprognostic.

MYCC and MYCN oncogene amplification in medulloblastoma. A fluorescence in situ hybridization study on paraffin sections from the Children's Oncology Group

CONTEXT

Brain tumors are the most common solid tumor in childhood, and medulloblastoma is the most common malignant brain tumor in this age group. Cytogenetic abnormalities that have been described in childhood medulloblastoma include loss of 17p, amplification of MYCC (c-myc), amplification of MYCN (N-myc), and isochromosome 17q. Data on these tumors indicate that the frequency of MYCC amplification is 5% to 10%. Fluorescence in situ hybridization is a powerful tool for investigating these features on archival material.

OBJECTIVES

To determine if intratumoral heterogeneity exists for MYCC and MYCN in medulloblastomas and if tumors with amplified MYCC or MYCN exhibit consistent histologic patterns.

DESIGN

In this fluorescence in situ hybridization study, we investigated the frequency and prognostic significance of MYCC and MYCN amplification in 77 medulloblastomas derived from the Children's Oncology Group.

RESULTS

MYCC amplification occurred in only 4 (5.2%) of 77 tumors. The 4 patients died of clinically aggressive neoplasms within 7 months of diagnosis. Similarly, 4 of 77 patients' tumors were found to exhibit MYCN amplification, but survival data are incomplete at present, therefore prognostic significance cannot be characterized.

CONCLUSIONS

These data establish the frequency of MYCC amplification in a large cohort of children with medulloblastoma and further suggest that MYCC amplification may be a marker of poor prognosis. Intratumoral heterogeneity was identified for these oncogenes in that 1 patient's tumor exhibited evidence of both MYCN and MYCC amplification, and this patient experienced a shortened survival time.