Vascular distribution of glioblastoma multiforme at diagnosis

Treatment of high-grade gliomas with selective intra-arterial (IA) administration of chemotherapies has been proposed, and utilized as a therapeutic modality. This approach offers the conceptual benefit of providing maximal delivery of the agent to the tumor bed, while potentially reducing systemic exposure to the agent. This retrospective study was designed to determine the vascular distribution of glioblastoma multiforme (GBM) at the time of diagnosis in an effort to determine what proportion of patients would likely be candidates for this approach. The preoperative MRI scans of 50 patients with GBM were analyzed and compared to published normative data of intracranial vascular distribution. Vascular distribution was determined by analyzing post-gadolinium axial and coronal T1 images, axial T2 images, and axial T2 images with an additional 1 cm margin (T2 + 1 cm) added in all dimensions. T1 analysis demonstrated 60% of tumors in a single vascular distribution. T2 analysis of these tumors reduced that number to 34%. When the T2 + 1 cm margin was utilized, only 6% of tumors were in a single vascular distribution. 66% of tumors were limited to the anterior circulation on T1 imaging but only 34% on T2 + 1 cm imaging. 30% of tumors were also within the distribution of the anterior choroidal artery. These findings suggest that the use of selective IA administration of agents is necessarily limited to a fraction of presenting patients or will require administration via multiple cerebral arteries.

Onset of adreno-leukodystrophy after medulloblastoma therapy: causal connection or coincidence?

X-linked adreno-leukodystrophy (ALD) is a peroxisomal disorder affecting the white matter of the central nervous system and the adrenal cortex. It is caused by mutations in the ABCD1 gene encoding for a peroxisomal membrane protein. The absent genotype-phenotype correlation implies a contribution by environmental factors to explain the phenotypical heterogeneity. We report on a 4-year-old boy with a biochemically confirmed diagnosis of ALD after birth. At the age of 32 months, the additional diagnosis of a medulloblastoma was made. After treatment of the medulloblastoma, he developed active areas of demyelination representing the characteristic neuroimaging features of ALD. The clinical history of our patient supports the hypothesis that external factors, like neurosurgical intervention as part of medulloblastoma treatment, may accelerate or initiate cerebral ALD-related demyelination. A postsurgical inflammatory reaction may facilitate the inclusion of abnormal fatty acids in myelin. The opening of the blood-brain barrier following neurosurgery may enhance the recognition of previously sequestered antigens considered to play a role in ALD onset. Consequently, neurosurgical disruption of the BBB can precipitate the immune-mediated inflammatory process, which progressively destroys myelin in ALD patients. Tumor-related chemotherapy and/or radiotherapy may also play a contributing role. We suggest that X-ALD patients who undergo neurosurgical intervention need close follow-up imaging to identify active demyelination early.

Low cerebellar vermis volumes and impaired neuropsychologic performance in children treated for brain tumors and leukemia

BACKGROUND AND PURPOSE

Injury of the cerebellar vermis may occur in children with brain malignancies. Because the vermis is involved in motor and cognitive functioning, the goal of this prospective longitudinal study was to evaluate treatment-related changes in vermal volumes and neuropsychologic performance in children receiving brain radiation of the cerebellum.

MATERIALS AND METHODS

Ten patients (mean age, 11.6 years) and 10 healthy children (mean age, 12.1 years) were examined. Lobar vermal volumes and performance on neuropsychologic tests evaluating motor, visual, verbal, attention, memory, and executive functions were assessed at baseline and at 6-month follow-up visits.

RESULTS

At baseline, lower mean vermal volumes and impaired performance on visual-spatial and fine-motor tasks were detected in patients. At 6-month follow-up, further decrease in vermal volumes was detected only in patients with medulloblastoma, who received the largest radiation doses to the entire vermis. The volume decrease was not associated with reduction in neuropsychologic performance compared with baseline. At 6-month follow-up, data from all subjects revealed an association between smaller vermal volumes and slower fine-motor speed and lower visual-spatial skills.

CONCLUSIONS

Reduced brain-tissue volumes following radiation have been reported previously in pediatric patients. In this study, lower vermal volumes were detected even earlier, before radiation treatment was initiated or completed. Six months postradiation, vermal volume decreases detected in patients with medulloblastoma were not accompanied by declines in already poor neuropsychologic performance. In addition to radiation, the presence of brain malignancies and preradiation treatment may be important factors affecting cerebellar vermis tissue.

Astroblastoma: clinicopathologic features and chromosomal abnormalities defined by comparative genomic hybridization

Astroblastomas are uncommon brain tumors whose classification and histogenesis have been debated. Precise criteria for diagnosis have been described only recently, but have not found wide acceptance. We report the clinical, radiographic, and histopathologic features of 20 astroblastomas, and the chromosomal alterations in seven cases as detected by comparative genomic hybridization (CGH). The tumors occurred both in children and young adults (average age, 14 years), most often as well circumscribed, peripheral, cerebral hemispheric masses. Radiographically, the lesions were contrast-enhancing and solid, often with a cystic component. All were characterized histologically by astroblastic pseudorosettes, and most displayed prominent perivascular hyalinization, regional hyaline changes, and pushing borders in regard to adjacent brain. Tumor cells were strongly immunoreactive for S-100 protein, GFAP, and vimentin. Staining for EMA was focal. Ten of 20 astroblastomas were classified as "well differentiated" and 10 were classified as "malignant," largely on the basis of hypercellular zones with increased mitotic indices, vascular proliferation, and necrosis with pseudopalisading. All 10 well differentiated lesions and 8 of 10 malignant lesions were completely resected. None of the well differentiated astroblastomas recurred within the limited follow-up period. Three malignant astroblastomas recurred, including two incompletely resected tumors, and one that had been totally resected. One patient died of disease following recurrence. The most frequent chromosomal alterations detected by CGH were gains of chromosome arm 20q (4/7 tumors) and chromosome 19 (3/7). The combination of these gains occurred in three, including two well differentiated and one malignant astroblastoma. Other alterations noted in two tumors each were losses on 9q, 10, and X. These chromosomal alterations are not typical of ependymoma or infiltrating astrocytic neoplasms, and suggest that astroblastomas may have a characteristic cytogenetic profile in addition to their distinctive clinical, radiographic, and histopathologic features.

Pediatric glial tumors

Glial neoplasms in children comprise many heterogeneous tumors that include pilocytic and fibrillary astrocytomas, ependymomas, and the diffuse intrinsic pontine gliomas. In contrast to adults, most of whom present with high-grade fibrillary neoplasms, alternate histologies represent most cases seen in the pediatric setting. In addition, although most adult gliomas are supratentorial in location, in pediatrics infratentorial tumors (posterior fossa and brain stem) predominate. We discuss three specific tumors: diffuse intrinsic pontine gliomas; pilocytic astrocytomas; and ependymomas. Maximal surgical resection is the mainstay of therapy for both pilocytic astrocytomas and ependymomas. Failure to achieve an optimal resection often results in progression and the need for further therapy for patients with pilocytic astrocytomas, and is ultimately fatal in most children with subtotally resected ependymomas. Surgical resection has no role in the treatment of pontine gliomas. Focal radiation therapy is included routinely in the treatment of ependymomas, and it has been shown to improve event-free survival. This therapy also is used in the treatment of pontine gliomas because radiation treatment appears to slow inevitable tumor progression. Radiation therapy in pilocytic astrocytomas is generally reserved for patients who progress after an initial surgical resection or for those patients with midline tumors; these patients are poor candidates for aggressive surgical resection. The role of chemotherapy in these tumors is in evolution. Chemotherapy for pilocytic astrocytomas, particularly in young children (for whom radiation therapy is avoided), appears to be effective in the treatment of a subset of patients. Up-front chemotherapy is generally reserved for the youngest children who present with ependymoma. In the recurrence setting, chemotherapy has shown some activity, although this approach is never curative. Despite the application of various chemotherapeutics and other biologic agents, none of these therapies has improved the prognosis for patients with the uniformly lethal pontine glioma.

Second surgery for recurrent pilocytic astrocytoma in children

Pilocytic astrocytoma (PA) is the most common childhood brain tumor. In cases where the tumor progresses or recurs following primary surgical resection, the appropriate treatment is unclear. Options include chemotherapy, radiation therapy, surgical resection or a combination thereof. To analyze the utility of further surgery, we performed a retrospective, single-institution review of pediatric patients with recurrent PAs from 1990 to 1999 who were treated with a second surgical resection. Patients were excluded if they received adjuvant chemotherapy or radiation therapy. Twenty cases were identified. Tumor locations included: cerebral hemisphere (3), cerebellum (7), optic pathway/hypothalamus (5), thalamus (1) and brainstem (4). The indication for 4 surgeries included an enlarging tumor-associated cyst. At second surgery, 10 of 20 patients had a gross total resection (GTR), 2 a near total resection (NTR), and the remaining 8 patients had a subtotal resection (STR). No patients have died. Two of 10 tumors after GTR, 0 of 2 tumors after NTR, and 7 of 8 tumors after STR had second recurrence/progression at a mean of 15 months (range 4-33 months) following second surgery. The remaining 11 patients are recurrence/progression-free at a mean of 40.7 months (range 19-119 months). Surgery for tumors or midline structures rarely resulted in a GTR (1 of 10 cases). Surgery for tumors located in the cerebral hemispheres or cerebellum resulted in GTR or NTR in all cases and can result in long periods of progression-free survival without further adjuvant treatment.

Pediatric neuroblastic brain tumors containing abundant neuropil and true rosettes

We have encountered a series of seven unusual neuroblastic pediatric central nervous system (CNS) neoplasms with a unique constellation of histologic, immunohistochemical, and ultrastructural features. The tumors presented in five girls and two boys, ages 1 to 3 years. In six cases the lesions involved the frontoparietal region, in one case the tectal plate. The tumors consisted of small to medium-sized, round to oval, hyperchromatic cells with poorly defined cytoplasmic borders. Cells were found in clusters and cords set in a paucicellular fibrillar neuropil matrix. Distinctive, virtually anuclear regions of neuropil were scattered throughout the lesions. True rosettes with well-formed central lumens often filled with granular debris were present, along with perivascular pseudorosettes and occasional Homer-Wright rosettes. Mitoses and apoptosis were frequent, but large regions of confluent necrosis were absent. Immunohistochemically, the neuropil-like areas as well as the perinuclear cytoplasm of many embryonal tumor cells were positive for synaptophysin and neurofilament protein. Ultrastructurally, the tumor cells showed microtubule-containing neuronal processes, some with neurosecretory granules. While the lesions were largely glial fibrillary acidic protein (GFAP) negative, there was focal GFAP positivity consistent with divergent differentiation in one case. The clinical outcome was poor, with five patients dead from their disease 5 to 14 months after initial presentation and one patient with recurrent disease 7 months after resection and chemotherapy. The final patient is alive without recurrent disease 30 months after initial presentation. These lesions present distinctive histological features within the group of primitive neuroectodermal tumors.

Pathology of diencephalic astrocytomas

Pediatric gliomas span a spectrum of neoplasms ranging from the well-circumscribed, slowly growing lesions that can be totally removed by surgery to highly infiltrating, nonexcisable, rapidly growing tumors that resist any form of postoperative therapy. As part of this symposium, we discuss selected members of this group in the diencephalon, where lesions of both extremes are common in children. The report illustrates and contrasts the clinical, radiographic and pathological features of the two classic regional astrocytomas, pilocytic and fibrillary, as well as two less common but distinctive lesions, pilomyxoid astrocytoma and bithalamic astrocytoma.

Tectal gliomas: natural history of an indolent lesion in pediatric patients

The mesencephalic tectal glioma is a distinctive form of brain stem glioma with an unusually benign clinical course. Periaqueductal location, lack of contrast enhancement, and long periods of stability are classic features. The clinical management of these lesions, especially at the time of radiographic enlargement varies widely in the published literature. It is unclear whether these progressive lesions need to be treated. Accordingly, clinical and radiologic features of 7 patients were reviewed, with attention to the clinical course of the disease after radiologic enlargement. The age at diagnosis ranged from 3.3 to 16.6 years. Six of 7 had MRI tumor enlargement beginning 0.3-5.7 years after initial diagnosis. One of these 6 patients had radiographic progression coupled with a new clinical symptom which was treated with stereotactic radiation therapy. The remaining 5 patients with MRI progression and normal neurological exams were not treated and remain free of new neurologic deficits 1.8-6.9 years after the first radiographic tumor enlargement. The results suggest that pediatric tectal gliomas are a very low-grade lesion. Conservative management in the absence of new clinical symptoms could be argued, reserving radiotherapy or chemotherapy for clinical progression.

Frequent detection of tumor cells in hematopoietic grafts in neuroblastoma and Ewing's sarcoma

Many poor-risk neuroblastomas and tumours of the Ewing's sarcoma family (ET) recur despite autologous transplants. Recurrence may be due to tumor cells contained in the BM harvests or PBSC harvests. The objectives of this prospective study were to: (1) determine the incidence and degree of tumor cell contamination in paired BM and PBSC harvests; and (2) determine the efficacy of tumor cell purging by immunomagnetic CD34+ cell selection. 198 samples from 11 consecutive patients with neuroblastoma or Ewing's sarcoma were analyzed. We assayed tumor contamination by RT-PCR assay for PGP 9.5, plus immunohistochemistry for neuroblastoma-specific antigens (the latter in neuroblastoma only). None of these patients had tumor cells detected in their BM by clinical histology immediately before BM or PBSC harvests. However, 82% of PBSC and 89% of backup BM harvests were contaminated with tumor by RT-PCR and/or immunocytochemistry assays. Unselected PBSC and BM harvests contained similar quantities of tumor cells (median, approximately 200000 cells). Cyclophosphamide plus G-CSF mobilization did not affect the incidence or level of contamination in PBSC harvests, as compared to blood obtained before mobilization. Immunomagnetic CD34+ cell selection depleted tumor cells by a median of 3.0 logs for PBSC, and 2.6 logs for BM harvests.

Transformation by the Bmi-1 oncoprotein correlates with its subnuclear localization but not its transcriptional suppression activity

The bmi-1 oncogene cooperates with c-myc in transgenic mice, resulting in accelerated lymphoma development. Altering the expression of Bmi-1 affects normal embryogenesis. The protein product of bmi-1 is homologous to certain Drosophila Polycomb group proteins that regulate homeotic gene expression through alteration of chromatin structure. Chimeric LexA-Bmi-1 protein has previously been shown to repress transcription. How Bmi-1 functions in embryogenesis and whether this relates to the ability of Bmi-1 to mediate cellular transformation is unknown. We demonstrate here that Bmi-1 is able to transform rodent fibroblasts in vitro, providing a system that has allowed us to correlate its molecular properties with its ability to transform cells. We map functional domains of Bmi-1 involved in transcriptional suppression by using the GAL4 chimeric transcriptional regulator system. Deletion analysis shows that the centrally located helix-turn-helix-turn-helix-turn (HTHTHT) motif is necessary for transcriptional suppression whereas the N-terminal RING finger domain is not required. We demonstrate that nuclear localization requires KRMK (residues 230 to 233) and that the absence of nuclear entry ablates transformation. In addition, we find that the subnuclear localization of wild-type Bmi-1 to the rim of the nucleus requires the RING finger domain and correlates with its ability to transform. Our studies with Bmi-1 deletion mutants suggest that the ability of Bmi-1 to mediate cellular transformation correlates with its unique subnuclear localization but not its transcriptional suppression activity.

The t(3;5)(q25.1;q34) of myelodysplastic syndrome and acute myeloid leukemia produces a novel fusion gene, NPM-MLF1

A t(3;5)(q25.1;q34) chromosomal translocation associated with myelodysplastic syndrome and acute myeloid leukemia (AML) was found to rearrange part of the nucleophosmin (NPM) gene on chromosome 5 with sequences from a novel gene on chromosome 3. Chimeric transcripts expressed by these cells contain 5' NPM coding sequences fused in-frame to those of the new gene, which we named myelodysplasia/myeloid leukemia factor 1 (MLF1). RNA-based polymerase chain reaction analysis revealed identical NPM-MLF1 mRNA fusions in each of the three t(3;5)-positive cases of AML examined. The predicted MLF1 amino acid sequence lacked homology to previously characterized proteins and did not contain known functional motifs. Normal MLF1 transcripts were expressed in a variety of tissues, most abundantly in testis, ovary, skeletal muscle, heart, kidney and colon. Anti-MLF1 antibodies detected the wild-type 31 kDa protein in K562 and HEL erythroleukemia cell lines, but not in HL-60, U937 or KG-1 myeloid leukemia lines. By contrast, t(3;5)-positive leukemia cells expressed a 54 kDa NPM-MLF1 protein, but not normal MLF1. Immunostaining experiments indicated that MLF1 is normally located in the cytoplasm, whereas NPM-MLF1 is targeted to the nucleus, with highest levels in the nucleolus. The nuclear/nucleolar localization of NPM-MLF1 mirrors that of NPM, indicating that NPM trafficking signals direct MLF1 to an inappropriate cellular compartment in myeloid leukemia cells.

Cessation of antibiotics regardless of ANC is safe in children with febrile neutropenia. A preliminary prospective trial

PURPOSE

This study was designed to evaluate the safety and efficacy of stopping antibiotic treatment regardless of absolute neutrophil count (ANC) or signs of impending neutrophil recovery in children with febrile neutropenia (FN) and no identifiable infectious source.

PATIENTS AND METHODS

Thirty-two consecutive cases of FN without identifiable source were prospectively evaluated. Patients were examined, cultured, and initially treated with ceftazidime +/- vancomycin. Antibiotics were discontinued and patients discharged regardless of ANC (WBC/microliter x [% segs + bands]) once all the following criteria were met: afebrile > or = 24 h; cultures negative at 48 h; thermometer and telephone available at home. Prompt notification of fever (T > 38.3 degrees C) and readmission were required.

RESULTS

Median ANC was 60/microliters on admission and 160/microliters at discharge. Median length of treatment was 3 days. Four patients were readmitted for FN, and two patients were readmitted afebrile for cultures which became positive after discharge. None of the 32 cases suffered apparent complications from early discharge.

CONCLUSION

Results of this preliminary trial suggest that cessation of antibiotics regardless of ANC is safe in cases of FN without identifiable source, provided that marrow is not infiltrated and that recurrent fever receives prompt antibiotic retreatment.

Participation of cyclin A in Myc-induced apoptosis

The involvement of c-Myc in cellular proliferation or apoptosis has been linked to differential cyclin gene expression. We observed that in both proliferating cells and cells undergoing apoptosis, cyclin A (but not B, C, D1, and E) mRNA level was elevated in unsynchronized Myc-overexpressing cells when compared with parental Rat1a fibroblasts. We further demonstrated that Zn(2+)-inducible cyclin A expression was sufficient to cause apoptosis. When Myc-induced apoptosis was blocked by coexpression of Bcl-2, the levels of cyclin C, D1, and E mRNAs were also elevated. Thus, while apoptosis induced by c-Myc is associated with an elevated cyclin A mRNA level, protection from apoptosis by coexpressed Bcl-2 is associated with a complementary increase in cyclin C, D1, and E mRNAs.