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Biomedical subjects

Andrew B Lassman

Publications and source records attributed to Andrew B Lassman.

12 recordsLinked to original sources
PubMed2006

Metastases to the pineal gland.

We identified 10 patients with symptomatic metastases to the pineal gland. We present the clinical and radiographic findings in this syndrome. Leptomeningeal metastases occur frequently and are a poor prognostic factor. In all cases, the primary cancer was clinically silent, either in remission (six cases) or previously undiagnosed (four cases). Hence, metastatic disease, albeit uncommon, should be considered in the differential diagnosis of pineal tumors.

Adult↗
PubMed2006

Systemic high-dose intravenous methotrexate for central nervous system metastases.

BACKGROUND: Treatment options for patients with recurrent central nervous system (CNS) metastases are limited. Rapid infusion of high-dose intravenous methotrexate (HD IV MTX) penetrates the blood-brain barrier (BBB) and has reported activity in leptomeningeal metastases. METHODS: Medical records were reviewed for all patients treated with HD IV MTX (3.5 g/m2) for CNS parenchymal or leptomeningeal metastases. Radiographic response rate, survival, and toxicity were determined. RESULTS: Thirty-one women and one man with a median age of 52 years (range 33-76) were treated with a total of 141 cycles (median 4, range 1-13). Twenty-nine patients had breast cancer, and one each had cancer of unknown primary (CUP), squamous cell carcinoma of the head and neck, and non-small cell lung cancer (NSCLC). An objective radiographic response and stable disease were each observed in nine patients (28%), and 13 (44%) patients progressed. Prior treatment with low-dose MTX for systemic disease did not affect response (P = 0.8). The median overall survival (n = 32) was 19.9 weeks (range 2.9-135.4+) with one patient alive at 135.4 weeks. Myelosuppression and elevated serum hepatic transaminases were the most common acute toxicities (21% and 9% of HD IV MTX cycles, respectively). CONCLUSIONS: HD IV MTX is effective in the treatment of CNS metastases with disease control (response or stable) as a best response in 56% of assessable patients. Further study is warranted.

Adult↗
PubMed2006

Glioma oncogenesis and animal models of glioma formation.

Recent advances in animal models have improved our understanding of the pathway abnormalities driving glioma growth. This article reviews key molecular abnormalities that have been modeled in mice, and describes major tumor modeling techniques along with examples of astrocytoma and oligodendroglioma models. Animal models are important not only for the testing of novel therapeutics but also as a means to understand the molecular explanations for treatment success and failure in humans.

Animals↗
PubMed2005

Salvage temozolomide for prior temozolomide responders.

BACKGROUND: Temozolomide (TMZ) often is used as adjuvant or first-line therapy for patients with glioma. Because of potential hematologic complications, it usually is discontinued after 12-18 cycles, even in responders. Subsequent salvage therapies are reported to have limited efficacy at the time of disease recurrence. In the current study, the authors assessed the outcome and complications of reusing TMZ at the time of disease recurrence in patients who previously responded to treatment. METHODS: A retrospective review of patients with recurrent/progressive glioma who had a history of response to TMZ and were treated with the same agent at the time of disease recurrence was conducted. RESULTS: Fourteen patients were identified (8 men and 6 women). The median age of the patients was 56 years (range, 25-67 yrs) at the time of diagnosis; 9 patients had glioblastoma, 3 had anaplastic astrocytoma, and 2 patients had low-grade oligodendroglioma. No patient developed disease progression while receiving the initial TMZ treatment. At the time of the initial disease recurrence, 13 patients were readministered TMZ. One patient received TMZ at the time of second disease recurrence. All patients were assessed for radiographic response. Objective response or stable disease was achieved in 6 patients (43%; 95% confidence interval [95% CI], 21-67%) and the 6-month progression-free survival was 36% (95% CI, 16-61%). CONCLUSIONS: TMZ was found to be well tolerated and effective in this setting, suggesting that repeat use of TMZ in previous responders warrants further investigation.

Adult↗
PubMed2005

Molecular study of malignant gliomas treated with epidermal growth factor receptor inhibitors: tissue analysis from North American Brain Tumor Consortium Trials 01-03 and 00-01.

PURPOSE: We investigated the molecular effect of the epidermal growth factor receptor (EGFR) inhibitors erlotinib and gefitinib in vivo on all available tumors from patients treated on North American Brain Tumor Consortium trials 01-03 and 00-01 for recurrent or progressive malignant glioma. EXPERIMENTAL DESIGN: EGFR expression and signaling during treatment with erlotinib or gefitinib were analyzed by Western blot and compared with pre-erlotinib/gefitinib-exposed tissue or unexposed controls. Tumors were also analyzed for EGFR mutations and for other genomic abnormalities by array-based comparative genomic hybridization. Clinical data were used to associate molecular features with tumor sensitivity to erlotinib or gefitinib. RESULTS: Erlotinib and gefitinib did not markedly affect EGFR activity in vivo. No lung signature mutations of EGFR exons 18 to 21 were observed. There was no clear association between erlotinib/gefitinib sensitivity and deletion or amplification events on array-based comparative genomic hybridization analysis, although novel genomic changes were identified. CONCLUSIONS: As erlotinib and gefitinib were generally ineffective at markedly inhibiting EGFR phosphorylation in these tumors, other assays may be needed to detect molecular effects. Additionally, the mechanism of erlotinib/gefitinib sensitivity likely differs between brain and lung tumors. Finally, novel genomic changes, including deletions of chromosomes 6, 21, and 22, represent new targets for further research.

Antineoplastic Agents↗
PubMed2005

Paroxysmal apnea and vasomotor instability following medullary infarction.

BACKGROUND: Central hypoventilation and paroxysmal hypertension are uncommon complications of medullary infarction. To our knowledge, the combination of these autonomic complications of medullary stroke has not previously been reported. OBJECTIVE: To describe a patient who experienced life-threatening paroxysmal attacks of central apnea and vasomotor instability 3 months after medullary infarction, a combination of symptoms that is unusual. PATIENT, METHODS, AND RESULTS: Following a right lateral medullary infarction, an otherwise stable 70-year-old woman developed recurrent episodes of apnea (PCO2), > 100 mm Hg), blood pressure instability (systolic blood pressure, > 200 to < 100 mm Hg), and mental status changes (from agitation to coma) within hours of removal from mechanical ventilation. These attacks occurred repeatedly after removal from mechanical ventilation and were prevented by diaphragm pacing with a phrenic nerve pacemaker and nocturnal mechanical ventilation via a tracheostomy. CONCLUSIONS: A syndrome of life-threatening central hypoventilation and vasomotor instability can occur after medullary infarction. Placement of a phrenic nerve pacemaker can prevent these complications, without the functional limitations imposed by continuous mechanical ventilation.

Aged↗
PubMed2004

Molecular biology of gliomas.

Gliomas are the most common primary neoplasm of the brain. Unfortunately, they are often refractory to treatment and portend a poor prognosis. However, recent discoveries have shed light on the molecular events driving glioma growth, including abnormalities of three major molecular pathways: extracellular growth factors and their receptors (eg, EGF/EGFR and PDGF/PDGFR), signal transduction cascades (eg, RAS and AKT), and cell proliferation controls (eg, INK4A-ARF). Each of these abnormalities is described in detail. Efforts to inhibit abnormally activated pathways are underway through multi-institutional clinical trials.

Brain Neoplasms↗
PubMed2004

Overexpression of c-MYC promotes an undifferentiated phenotype in cultured astrocytes and allows elevated Ras and Akt signaling to induce gliomas from GFAP-expressing cells in mice.

The c-MYC protooncogene is overexpressed in the most malignant primary brain tumor, glioblastoma multiforme (GBM), and has been correlated with the undifferentiated character of several cell types. However, the role of Myc activity in the generation of GBMs is not known. In this report, we show that gene transfer of c-MYC to GFAP-expressing astrocytes in vitro promotes the outgrowth of GFAP-negative, nestin-expressing cells with progenitor-like morphology, growth characteristics and gene-expression pattern. In addition, gene transfer of c-MYC to GFAP-expressing astrocytes in vivo induces GBMs when co-expressed with activated Ras and Akt. Without c-MYC, Ras+Akt induces GBMs from nestin-expressing CNS progenitors but is insufficient in GFAP-expressing differentiated astrocytes. The ability of Myc activity to enhance the oncogenic effects of Ras+Akt appears to be limited to GFAP-expressing astrocytes because nestin-expressing progenitors show no increase in GBM formation with the addition of MYC to Ras+Akt. These studies indicate that one role of MYC activity in the formation of gliomas might be to either promote or reinforce an undifferentiated phenotype required for glioma cells to respond to the oncogenic effects of elevated Ras and Akt activity.

Journal Article↗
PubMed2003

Brain metastases.

Brain metastases are one of the most feared complications of cancer because even small tumors may cause incapacitating neurologic symptoms. This article reviews the epidemiology, clinical features, treatment, and prognosis of brain metastases from system malignancies.

Brain Neoplasms↗