[Biochemistry of brain tumor--brain tumor protein and immune reactions (author's transl)].
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Animals↗
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Results for “BRAIN TUMOR”
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Current status of therapy of solid tumors: brain tumor therapy.
Treatment of malignant brain tumors with conventional approaches is largely unsuccessful because curative doses generally cannot be delivered without excessive toxicity to normal brain. Radioimmunotherapy is emerging as an attractive alternative for glioma therapy because of the potential for more selectively irradiating tumor cells while sparing normal tissues. Several institutions are engaged in phase I and phase II trials investigating the therapeutic potential of monoclonal antibodies (mAbs) labeled with the beta-emitters (131)I and (90)Y and the alpha-emitter (211)At in patients with recurrent and newly diagnosed brain tumors. The current status of these trials will be discussed with regard to efficacy, toxicity, and future directions.
Animals↗
Treatment options in high-grade brain tumors: brain brachytherapy.
The extremely poor prognosis of high-grade brain tumors (glioblastoma multiforme and anaplastic astrocytomas) has been well documented in the literature. Almost 90% of patients die within 18 months after therapy, most commonly because of local persistence of the tumor, which may be controlled if a sufficient amount of irradiation can be delivered. Currently, postoperative radiation therapy offers the best median survival rate. However, the response to external-beam radiation therapy has reached a plateau because of the intolerance of healthy brain tissue to excessive irradiation. To treat these tumors, brachytherapy (interstitial implantation of radioactive sources) can be used with debulking surgery. This therapy is becoming an effective alternative to conventional external-beam radiation therapy, since it allows a higher dose to be delivered to the tumor bed without damaging the surrounding healthy brain tissue. With continual refinements of the technique, brachytherapy, performed by a skilled brachytherapy team, offers an opportunity to improve patient survival.
Astrocytoma↗
[Metastatic tumors, brain tumors].
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Brain Neoplasms↗
[ON THE DIFFERENTIAL DIAGNOSIS OF INTRACRANIAL GRANULOMATOUS TUMORS (BRAIN TUMOR IN BESNIER-BOECK-SCHAUMANN DISEASE)].
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Brain Diseases↗
[The blood-brain barrier. II. Pathology: brain tumors, brain edema, hypertension, epilepsy].
In the first part of the publication the authors presented the blood-brain (BBB) under physiological conditions. The second part includes the current opinions concerning BBB during various disorders of the central nervous system (CNS) and hypertension. The imbalance of BBB is often not only a consequence of a pathologic status, but can be also cause of it. On the other hand BBB influences the therapy of many illnesses by restricting the penetration of drugs to the CNS.
Adrenal Cortex Hormones↗
Perfusion MR imaging of brain tumors.
Brain tumors rank second as the cause of cancer-related deaths in children and adults younger than 34 years old, and they are seen in adults of all ages. Primary malignant brain tumors are associated with the third highest cancer-related mortality rate and a disproportionate level of disability and morbidity. Considering this, accurate diagnosis and grading of brain tumors are critical to determining prognosis and therapy. Equally important is to evaluate for tumor status during therapy to assess for therapeutic response and treatment-related complications. Brain tumors can be characterized as a heterogeneous group of neoplasm with a correspondingly wide variation in malignant phenotype and a diverse array of imaging features. Magnetic resonance (MR) imaging with intravenous contrast agent is the test of choice to diagnose and monitor brain tumors before, during, and after therapy. Recent advances in imaging methods such as diffusion-weighted imaging, perfusion imaging, and spectroscopic imaging all have in common the ability to provide quantitative cellular, hemodynamic, and metabolic information that may enhance our understanding of brain tumor biology, help us to better assess treatment response, more accurately determine tumor activity during therapy, and differentiate recurrent tumor and treatment related complications. In this article, we will review the basics of brain tumor imaging and focus on the role of perfusion MR imaging in improving accurate diagnosis and monitoring brain tumors during therapy. Both strengths and shortcomings of perfusion MR imaging over standard anatomic MR imaging will be discussed as will important pitfalls of the technique.
Brain Neoplasms↗
Epidemiology of pediatric brain tumors.
Brain tumor research is unlike some other areas of cancer research, in which definite causes have been identified and prevention and treatment strategies may be developed. Primary brain tumors are heterogeneous with respect to several characteristics, and brain tumor research is hampered by this fact, as well as by the small numbers of cases, by the lack of a clearly established and consistently applied histopathologic classification scheme, and by geographical variations in diagnostic capabilities and mechanisms for case reporting. The current movement toward molecular epidemiology has resulted in several changes in the ways we will be able to investigate cancer etiologies in the future, and promises to be especially fruitful in the area of brain tumor research. The search is under way for biologic markers of risk exposures for various cancers, and for laboratory methods to identify those individuals who, because of their genetic qualities, are most likely to have brain tumors. There are probably multiple causes for brain tumors, incorporating both genetic and environmental pathways. Prior research has consistently identified few risk factors for brain tumors, such as ionizing radiation. Thus, collaborative efforts among clinicians, laboratory scientists, and epidemiologists, which make use of molecular epidemiologic methods, are perhaps of greater importance in this field than for cancers arising at other sites.
Brain↗
Nonmalignant pediatric brain tumors.
Brain tumors are the most common solid neoplasms in the pediatric population. Each year in the United States, approximately 1500 to 2000 children are affected by one of these tumors. About 50% of pediatric brain tumors are malignant. Nonmalignant pediatric brain tumors comprise an eclectic group of pathologic entities that have fascinating clinical features. Many of these tumors demonstrate a favorable prognosis. In this report, we review the epidemiology, histopathology, genetics, clinical presentation, neuroimaging, and treatment of the common nonmalignant pediatric brain tumors, including low grade astrocytomas (such as cerebellar astrocytoma and optic pathway glioma), subependymal giant cell astrocytomas, central neurocytomas, dysembryoplastic neuroepithelial tumor, choroid plexus papilloma, and craniopharyngioma. Advances in the therapeutic management of patients with these tumors have considerably improved their prognosis.
Adolescent↗
Maternal consumption of cured meats and vitamins in relation to pediatric brain tumors.
Brain tumors are the leading cause of death from childhood cancer, yet the causes of most of these tumors remain obscure. Few chemicals are effective in causing brain tumors experimentally after systemic administration of low doses; a notable exception is one group of N-nitroso compounds, the nitrosamides (in particular the nitrosoureas). Feeding pregnant animals nitrosamide precursors (e.g., sodium nitrite and an alkylamide such as ethylurea) causes a high incidence of nervous system tumors in offspring. This population-based epidemiological study was designed to test the hypothesis that maternal consumption during pregnancy of meats cured with sodium nitrite increases the risk of brain tumors among offspring. The intake of vitamins C and E blocks endogenous formation of nitroso compounds and was expected to be protective. Mothers of 540 children under age 20 with a primary brain tumor diagnosed during 1984-1991 and 801 control children in the same 19 counties on the U.S. West Coast were interviewed. Risk increased with increasing frequency of eating processed meats [odds ratio (OR) = 2.1 for eating at least twice a day compared to not eating; 95% confidence interval (CI) = 1.3-3.2; P = 0.003). Risk also increased with increasing average daily grams of cured meats or mg of nitrite from cured meats (P for each <0.005) but not with nitrate from vegetables. Daily use of prenatal vitamins throughout the pregnancy decreased risk (OR = 0.54; CI = 0.39-0.75). Risk among mothers who consumed above the median level of nitrite from cured meat was greater if vitamins were not taken (OR = 2.4; CI = 1.4-3.6) than if they were (OR = 1.3). These effects were evident for each of three major histological types and across social classes, age groups, and geographic areas. This largest study to date of maternal diet and childhood brain tumors suggests that exposure during gestation to endogenously formed nitroso compounds may be associated with tumor occurrence. Laboratory exploration is needed to: (a) define dietary sources of exposure to alkylamides; (b) investigate the reactivity of nitrite in high concentration such as around bits of cured meats in the stomach after ingestion compared to nitrite in dilute solution; and (c) confirm that simultaneous ingestion of alkylamides and cured meats leads to the endogenous formation of nitrosamides.
Adolescent↗
Cytogenetic studies in 45 pediatric brain tumors.
Brain tumors are the most frequent childhood tumors. There have been few cytogenetic studies published on these tumors in children compared to the numerous studies on adult brain tumors. We examined chromosomes from 45 primary pediatric brain neoplasms including 14 medulloblastomas, 12 astrocytomas, 4 glioblastomas, 7 ependymomas, 5 craniopharyngiomas, 2 meningiomas, and 1 ganglioglioma. Chromosomal abnormalities were found in 10 medulloblastomas out of the 14 analyzed. The most frequently observed abnormalities were the total or partial loss of one chromosome 17: monosomy 17, i(17q), and a monosomy 22 in 4 cases of desmoplastic medulloblastoma. In glioblastoma, we observed the gain of chromosome 7, chromosome 3, a monosomy 10, and hyperdiploidy. The loss of chromosome X was observed in 2 cases of ependymoma as was a monosomy 22. Our observations show that from the cytogenetic point of view childhood brain tumors differ from adult brain tumors.
Brain Neoplasms↗
Genetics of brain tumors.
Brain tumors are among the most common forms of cancer in children and account for most cancer-related deaths in this age group. The incidence of brain tumors appears to be increasing in children, while therapeutic advances have been modest. Few genetic studies exist on pediatric brain tumors, in part because tissue from low-grade and brain stem tumors is not readily available, and also because individual centers have relatively few cases. Genetic changes in infiltrating astrocytomas involve genes in the p53 and RB pathways, and show alterations that are similar to infiltrating astrocytomas in adults. The PTC gene is mutated in a subgroup of medulloblastomas, and may lead to increased proliferation in granule cells that normally express this receptor. Further studies are needed to identify genetic alterations in pilocytic and low-grade astrocytomas, which account for 40% of brain tumors in children.
Astrocytoma↗
Brain tumors.
Brain tumors are a relatively common cancer in all age groups, and the incidence of both primary and metastatic brain tumors is increasing. Fortunately, dramatic advances in methods of diagnosis, surgical technique, and adjuvant therapy have all contributed to an improved outlook for patients with brain tumors. This article reviews the classification, symptoms, diagnosis, and treatment of brain tumors.
Adult↗
Advances in the treatment of pediatric brain tumors.
Brain tumors are a heterogeneous group of neoplasms with different origins, pathobiologies, treatments and prognoses. The collective contributions from the fields of neuro-oncology, neurosurgery, radiation oncology, neurology, neuropathology, neuroradiology and molecular biology have all led to significant advances in the treatment of certain brain tumors. Ideas from these fields, under the cooperative umbrella of clinical cancer trial consortia, have been tested in large-scale studies. As a result, patient survivals have increased markedly for these tumor types. Unfortunately, there are certain brain tumors in childhood, such as the diffuse intrinsic pontine glioma and atypical teratoid rhabdoid tumor, for which survival advantages have not been found. This review will discuss the current and possible future therapies of the most common pediatric brain tumors and highlight some of the novel imaging modalities that are used pre- and intraoperatively.
Astrocytoma↗
Getting at the root and stem of brain tumors.
Brain tumors are among the most aggressive and intractable types of cancer. Recent studies indicate that brain tumor cells resemble neural stem cells in terms of phenotype, signaling, and behavior in vitro. In light of these similarities, it has been suggested that brain tumors arise from stem cells, that they co-opt stem cell strategies for self-renewal, and even that they contain "cancer stem cells" that are critical for tumor maintenance. We will examine these possibilities and discuss their implications for the understanding and treatment of brain tumors.
Animals↗
[Brain tumors].
Brain tumors generally arise as the culmination of a multistep process that involves a variety of genetic abnormalities. Theoretically, replacement of abnormal genes with normal genes is essential to brain tumor treatment. However, it is very difficult to replace all damaged genes. Currently, most clinical protocols for gene therapy in brain tumors include transfer of a gene which can induce tumor cells to die or which can enhance the environment to generate a systemic immune response against the tumor. The former strategy includes suicide gene therapies, tumor suppressor gene therapy and oncolytic virus therapy. The latter adopts immunogene therapy. In this report, we also focus on other gene therapies, such as therapies to control the cell cycle or apoptosis, and promote antiangiogenesis. Gene therapy is generally accepted to be rather safe in recent years. In fact, the current single-gene therapies for brain tumor are limited and probably restricted to a few tumors. Several agents with different mechanisms of action would be necessary to kill heterogenously mixed tumor cells. Further molecular techniques and basic studies may overcome the malignancy of cancers.
Adenoviridae↗
[Pneumocystis carinii pneumonia complicating brain tumor].
Brain tumors are frequently treated with steroids due to the presence of peritumoral edema. However, in Japan it is not widely recognized that primary brain tumor patients who are receiving steroid therapy become susceptible to Pneumocystis carinii pneumonia (PCP). We reviewed the clinical features and risk factors for PCP in brain tumor patients treated at our institution between 1994 and 2002. The treated cases consisted of 6 men and 6 women ranging in age from 47 to 78 yr (mean age 65.3). Underlying diseases included malignant glioma in 9 patients, malignant lymphoma in 2 patients and meningioma in one patient. All were diagnosed by respiratory disease specialists using bronchial washings and bronchoalveolar lavage or chest X ray/CT image. Radiation therapies were administered with 20 to 60 Gy (mean 52.9 Gy) except in one patient. Chemotherapy was performed with ranimustine in 4 malignant glioma patients and with methotrexate in 2 malignant lymphoma patients. Prednisone, begun perioperatively, was reduced gradually from a mean initial dosage of 38.3 mg/day orally. The duration of steroid treatment at the onset of PCP in these patients ranged from 41 to 79 days (mean 61.4 days). Six patients (50%) died of PCP despite appropriate antibiotic therapy and 2 patients needed intensive therapy with a respirator. For early diagnosis of PCP, periodic serological (e.g.; the level of lactate dehydrogenase and beta-D-glucan) and radiological examination (e.g.; chest X ray and CT image) is indicated in patients with brain tumors, and prophylaxis against PCP might be needed for patients with intracranial neoplasms and who are also receiving high-dose and long-term steroid treatment.
Aged↗
[Radiation therapy for brain tumors].
Brain tumors respond differently to treatment with surgery plus radiotherapy or radiotherapy alone, combined with or without chemotherapy, because they are characterized by subtypes with different histologies. Since the development of diagnostic radiology, such as computed tomography (CT) and magnetic resonance imaging (MRI), brain tumors have been easier to demonstrate and can be found at earlier stages than in the conventional situation. Furthermore, highly technical devices and equipment for radiation therapy have been developed and installed for clinical use, especially with multileaf collimator (MLC) and treatment planning systems. In the field of radiotherapy for brain tumors, it has been possible to use more precise treatment planning with conformal radiotherapy, three-dimensional treatment planning, and stereotactic radiotherapy. Dose escalation studies and the modified fractionation schedule of radiotherapy can also be designed by analyzing biological data and applying hypofractionated intensity-modulated radiotherapy (IMRT) to radioresistant tumors such as glioblastoma multiforme and anaplastic astrocytoma. Future investigation may be useful to determine which fraction size is likely to be optimal for these malignant gliomas when highly conformal radiotherapy is used in adjuvant treatment. These technological developments and newly designed radiosensitizing agents will improve local control rates and survival times, thereby enhancing the quality of life in patients suffering from various kinds of brain tumors.
Astrocytoma↗