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Glioma | |
---|---|
Glioma in the left parietal lobe (brain CT scan), WHO grade 2 | |
Specialty | Oncology, Neurology |
Risk factors | Advanced age, ionizing radiation [1] |
Diagnostic method | Brain imaging [1] |
A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are cancerous but some are extremely slow to develop. [2] [3] Gliomas comprise about 30 percent of all brain tumors and central nervous system tumours, and 80 percent of all malignant brain tumours. [4]
Symptoms of gliomas depend on which part of the central nervous system is affected. A brain glioma can cause headaches, vomiting, seizures, and cranial nerve disorders as a result of increased intracranial pressure. Also, different cognitive impairments can arise as a sign of tumor growth. [5] A glioma of the optic nerve can cause vision loss. Spinal cord gliomas can cause pain, weakness, or numbness in the extremities. Gliomas do not usually metastasize by the bloodstream, but they can spread via the cerebrospinal fluid and cause "drop metastases" to the spinal cord. Complex visual hallucinations have been described as a symptom of low-grade glioma. [6]
A child who has a subacute disorder of the central nervous system that produces cranial nerve abnormalities (especially of cranial nerve VII and the lower bulbar nerves), long-tract signs, unsteady gait secondary to spasticity, and some behavioral changes is most likely to have a pontine glioma. [7]
The exact causes of gliomas are not known. Hereditary disorders such as neurofibromatoses (type 1 and type 2) and tuberous sclerosis complex are known to predispose to their development. [8] Different oncogenes can cooperate in the development of gliomas. [9]
The best-known risk factor is exposure to ionizing radiation, and CT scan radiation is an important cause. [10] [11] The dose-response for the relationship between low-dose ionising radiation and glioma risk is a risk increase of 55% per 100 milligray of radiation. [10] A link between gliomas and electromagnetic radiation from cell phones has not been conclusively proven. [12] It was considered possible, [13] [14] though several large studies have found no conclusive evidence, as summarized by the NIH's National Cancer Institute review of the topic [15] and its numerous citations, [16] and the FCC. [17] However, further research is still being pursued to obtain more robust evidence and verify that there is no relationship (the NIH's National Institute of Environmental Health Sciences most recent press release discussed an ongoing study [18] showing mildly positive results, [19] although it appears there may have been issues with the control group dying prematurely [20] ).
Some studies have reported that glioblastomas are infected with cytomegalovirus, with suggestions that this may speed the development of tumors. [21] [22] [23] However, this is a controversial opinion, with recent in-depth studies failing to find an association between viral infection and glioma growth. [24] There is also evidence that previous studies may have been impacted by false-positive antibody staining artifacts. [25]
Studies have shown that farmers have higher rates of gliomas compared to the general population. In a 2021 meta-analysis, 40 of 52 studies since 1998 reported positive associations between farming and brain cancer with effect estimates ranging from 1.03 to 6.53, of which 80% are gliomas. Livestock farming was associated with a greater risk compared with crop farming. Farmers with documented exposure to pesticides had greater than a 20% elevated risk of brain cancer [26] [ unreliable source? ] The TRACTOR project study, including 1017 brain tumors among 1 036 069 farm managers, published in 2022, showed an increased risk of glioma in pig farming (HR = 2.28), crop farming (HR = 1.28) and fruit arboriculture (HR = 1.72) [27] [ medical citation needed ]
Data show that architects, surveyors, retail workers, butchers, and engineers have higher rates of gliomas. [28]
Germ-line (inherited) polymorphisms of the DNA repair genes ERCC1 , ERCC2 (XPD) and XRCC1 increase the risk of glioma. [29] This indicates that altered or deficient repair of DNA damage contributes to the formation of gliomas. DNA damages are a likely major primary cause of progression to cancer in general. [30] Excess DNA damages can give rise to mutations through translesion synthesis. Furthermore, incomplete DNA repair can give rise to epigenetic alterations or epimutations. [31] [32] Such mutations and epimutations may provide a cell with a proliferative advantage which can then, by a process of natural selection, lead to progression to cancer. [30]
Epigenetic repression of DNA repair genes is often found in progression to sporadic glioblastoma. For instance, methylation of the DNA repair gene MGMT promoter was observed in 51% to 66% of glioblastoma specimens. [33] [34] In addition, in some glioblastomas, the MGMT protein is deficient due to another type of epigenetic alteration. MGMT protein expression may also be reduced due to increased levels of a microRNA that inhibits the ability of the MGMT messenger RNA to produce the MGMT protein. [34] Zhang et al. [35] found, in the glioblastomas without methylated MGMT promoters, that the level of microRNA miR-181d is inversely correlated with protein expression of MGMT and that the direct target of miR-181d is the MGMT mRNA 3'UTR (the three prime untranslated region of MGMT messenger RNA). [36]
Epigenetic reductions in expression of another DNA repair protein, ERCC1 , were found in an assortment of 32 gliomas. [37] For 17 of the 32 (53%) of the gliomas tested, ERCC1 protein expression was reduced or absent. In the case of 12 gliomas (37.5%) this reduction was due to methylation of the ERCC1 promoter. For the other 5 gliomas with reduced ERCC1 protein expression, the reduction could have been due to epigenetic alterations in microRNAs that affect ERCC1 expression. [38]
When expression of DNA repair genes is reduced, DNA damages accumulate in cells at a higher than normal level, and such excess damages cause increased frequencies of mutation. [39] [40] [41] Mutations in gliomas frequently occur in either isocitrate dehydrogenase (IDH) 1 or 2 genes. [42] One of these mutations (mostly in IDH1) occurs in about 80% of low grade gliomas and secondary high-grade gliomas. [43] Wang et al. [44] pointed out that IDH1 and IDH2 mutant cells produce an excess metabolic intermediate, 2-hydroxyglutarate, which binds to catalytic sites in key enzymes that are important in altering histone and DNA promoter methylation. Thus, mutations in IDH1 and IDH2 generate a "DNA CpG island methylator phenotype or CIMP" [45] [46] that causes promoter hypermethylation and concomitant silencing of tumor suppressor genes such as DNA repair genes MGMT and ERCC1. On the other hand, Cohen et al. [43] and Molenaar et al. [42] pointed out that mutations in IDH1 or IDH2 can cause increased oxidative stress. Increased oxidative damage to DNA could be mutagenic. This is supported by an increased number of DNA double-strand breaks in IDH1-mutated glioma cells. [47] Thus, IDH1 or IDH2 mutations act as driver mutations in glioma carcinogenesis, though it is not clear by which role they are primarily acting. A study, involving 51 patients with brain gliomas who had two or more biopsies over time, showed that mutation in the IDH1 gene occurred prior to the occurrence of a p53 mutation or a 1p/19q loss of heterozygosity, indicating that an IDH1 mutation is an early driver mutation. [48]
High-grade gliomas are highly vascular tumors and have a tendency to infiltrate diffusely. [49] They have extensive areas of necrosis and hypoxia. Often, tumor growth causes a breakdown of the blood–brain barrier in the vicinity of the tumor. As a rule, high-grade gliomas almost always grow back even after complete surgical excision, so are commonly called recurrent cancer of the brain.[ medical citation needed ] [50]
Conversely, low-grade gliomas grow slowly, often over many years, and can be followed without treatment unless they grow and cause symptoms.[ medical citation needed ]
Several acquired (not inherited) genetic mutations have been found in gliomas. Tumor suppressor protein 53 (p53) is mutated early in the disease. [51] p53 is the "guardian of the genome", which, during DNA and cell duplication, makes sure the DNA is copied correctly and destroys the cell (apoptosis) if the DNA is mutated and cannot be fixed. When p53 itself is mutated, other mutations can survive. Phosphatase and tensin homolog (PTEN), another tumor suppressor gene, is itself lost or mutated. Epidermal growth factor receptor, a growth factor that normally stimulates cells to divide, is amplified and stimulates cells to divide too much. Together, these mutations lead to cells dividing uncontrollably, a hallmark of cancer. In 2009, mutations in IDH1 and IDH2 were found to be part of the mechanism and associated with a less favorable prognosis. [52]
Gliomas are named according to the specific type of cell with which they share histological features, but not necessarily from which they originate. The main types of glioma are: [53]
Gliomas are further categorised according to their grade, which is determined by pathologic evaluation of the tumor. The neuropathological evaluation and diagnostics of brain tumor specimens is performed according to WHO Classification of Tumours of the Central Nervous System. [55] [56]
Of numerous grading systems in use, the most common is the World Health Organization (WHO) grading system for astrocytoma, under which tumors are graded from I (least advanced disease—best prognosis) to IV (most advanced disease—worst prognosis).
Gliomas can be classified according to whether they are above or below a membrane in the brain called the tentorium. [58] The tentorium separates the cerebrum (above) from the cerebellum (below).
The modern approach to the diagnosis of diffuse gliomas takes mainly the histopathology and molecular profile into account. [61] Tissue specimens obtained through biopsy sampling in patients with diffuse gliomas are routinely assessed by immunohistochemistry for the presence of R132H-mutant IDH1 and loss of nuclear ATRX. [61] In patients aged >55 years with a histologically typical glioblastoma, without a pre-existing lower grade glioma, with a non-midline tumor location and with retained nuclear ATRX expression, immunohistochemical negativity for IDH1 R132H suffices for the classification as IDH-wild-type glioblastoma. [61] In all other instances of diffuse gliomas, a lack of IDH1 R132H immunopositivity should be followed by IDH1 and IDH2 DNA sequencing to detect or exclude the presence of non-canonical mutations. [61] IDH-wild-type diffuse astrocytic gliomas without microvascular proliferation or necrosis should be tested for EGFR amplification, TERT promoter mutation and a +7/–10 cytogenetic signature as molecular characteristics of IDH-wild-type glioblastomas. [61] In addition, the presence of histone H3.3 G34R/V mutations should be assessed by immunohistochemistry or DNA sequencing to identify H3.3 G34-mutant diffuse hemispheric gliomas, in particular in young patients with IDH-wild-type gliomas (such as those <50 years of age with nuclear ATRX loss in tumour cells). [61] Diffuse gliomas of the thalamus, brainstem or spinal cord should be evaluated for histone H3 K27M mutations and loss of nuclear K27-trimethylated histone H3 (H3K27me3) to identify H3 K27M-mutant diffuse midline gliomas. [61]
Treatment for brain gliomas depends on the location, the cell type, and the grade of malignancy. Current treatment options include surgical removal, radiation (radiation therapy), and chemotherapy. In some cases, tumour treating fields (alternating electric field therapy), a recently developed technology, may be used. [62] Often, treatment is a combined approach, using surgery, radiation therapy, and chemotherapy. For many, treatment consists of just surgery, or even "watchful waiting" (waiting to see when an intervention is justified due to tumour progression). Doctors carefully balance the specifics of the patient's tumour and the downsides of intervention, since there can be significant side effects from medical intervention, despite recent attempts to predict outcomes have been proposed. [63]
Awake surgery can be performed to monitor for example language and other cognitive functions, as well as motor functions and vision. [64] Awake surgery is known to improve extent of resection while perserving functions [65] and exetent of resection is directly associated with survival in low-grade gliomas. [66]
Radiation and chemotherapy remain the mainstays of treatment beyond surgery. Radiation therapy is delivered in the form of external beam radiation or the stereotactic approach using radiosurgery. Temozolomide is a common chemotherapy drug which can be administered easily in an outpatient setting and is able to cross the blood–brain barrier effectively.
There are a wide variety of novel treatments currently being tested in clinical trials, ranging from IDH inhibitors like Ivosidenib, to the recently approved Dendritic cell-based cancer vaccine approach. [67] Treatment using immunotherapy is another promising research path that may help treat glioma in the near future. [68] [69] Experimental therapies like oncolytic viruses have shown potential therapeutic benefits in clinical trials (but have not been approved for use in non-experimental settings). [70]
For recurrent high-grade glioblastoma, recent studies have taken advantage of angiogenic blockers such as bevacizumab in combination with conventional chemotherapy, with encouraging results. [71]
A 2017 meta-analysis compared surgical resection versus biopsy as the initial surgical management option for a person with a low-grade glioma. [72] Results show the evidence is insufficient to make a reliable decision. [72] The relative effectiveness of surgical resection compared to biopsy for people with malignant glioma (high-grade) is unknown. [73]
For high-grade gliomas, a 2003 meta-analysis compared radiotherapy with radiotherapy and chemotherapy. It showed a small but clear improvement from using chemotherapy with radiotherapy. [74] A 2019 meta-analysis suggested that for people with less aggressive gliomas, radiotherapy may increase the risk of long term neurocognitive side effects. [75] Whilst, evidence is uncertain on whether there are long term neurocognitive side effects associated with chemoradiotherapy. [75]
Temozolomide is effective for treating Glioblastoma Multiforme (GBM) compared to radiotherapy alone. [67] A 2013 meta-analysis showed that Temozolomide prolongs survival and delays progression, but is associated with an increase in side effects such as blood complications, fatigue, and infection. [67] For people with recurrent GBM, when comparing temozolomide with chemotherapy, there may be an improvement in the time-to-progression and the person's quality of life, but no improvement in overall survival, with temozolomide treatment. [67] Evidence suggests that for people with recurrent high-grade gliomas who have not had chemotherapy before, there are similar survival and time-to-progression outcomes between treatment with temozolomide or the chemotherapy multidrug known as PCV (procarvazine, lomustine and vincristine). [76]
A mutational analysis of 23 initial low-grade gliomas and recurrent tumors from the same patients has challenged the benefits and usage of Temozolomide. The study showed that when lower-grade brain tumors of patients are removed and patients are further treated with Temozolomide, 6 out of 10 times the recurrent tumors were more aggressive and acquired alternative and more mutations. [77] As one of the last authors, Costello, stated "They had a 20- to 50-fold increase in the number of mutations. A patient who received surgery alone who might have had 50 mutations in the initial tumor and 60 in the recurrence. But patients who received TMZ might have 2,000 mutations in the recurrence." [78] Further, new mutations were verified to carry known signatures of Temozolomide induced mutations. The research suggests that Temozolomide for the treatment of certain brain tumors should be thoroughly thought. Unjudicious usage of Temozolomide might lower the prognosis of the patients further, or increase their burden. Further understanding of the mechanisms of Temozolomide induced mutations and novel combination approaches could be promising.[ medical citation needed ]
Newcastle disease has been noted to be helpful in some cases of glioma. [79] Phase III trials with Newcastle Disease Virus Vaccine (MTH-68/H) are expected soon. Strains of Newcastle disease virus have also been used to create viral vector vaccine candidates against Ebola and Covid-19. [80] Torticollis in foul shows the level of avian severity.
This section needs to be updated.(September 2020) |
Prognosis of gliomas is given in relation to what grade (as scored by the World Health Organization system) of tumour the patient presents with. Typically, any tumour presenting as above WHO grade I (i.e. a malignant tumour as opposed to a benign tumour) will have a prognosis resulting in eventual death, varying from years (WHO grade II/III) to months (WHO grade IV). [49] [81] Prognosis can also be given based on cellular subtype, which may also impact prognosis.
For low-grade tumors, the prognosis is somewhat more optimistic. Patients diagnosed with a low-grade glioma are 17 times as likely to die as matched patients in the general population. [82] The age-standardized 10-year relative survival rate was 47% according to research in 2014. [82] One study reported that low-grade oligodendroglioma patients have a median survival of 11.6 years; [83] another reported a median survival of 16.7 years. [84] Unfortunately, approximately 70% of low-grade (WHO grade-II) will progress to high-grade tumours within 5–10 years [49] Grade II gliomas, despite often being labeled as benign, are considered a uniformly fatal illness. [85]
This group comprises anaplastic astrocytomas and glioblastoma multiforme. Whereas the median overall survival of anaplastic (WHO grade III) gliomas is approximately 3 years, glioblastoma multiforme has a poor median overall survival of c. 15 months. [86]
Postoperative conventional daily radiotherapy improves survival for adults with good functional well‐being and high grade glioma compared to no postoperative radiotherapy. Hypofractionated radiation therapy has similar efficacy for survival as compared to conventional radiotherapy, particularly for individuals aged 60 and older with glioblastoma. [87]
Diffuse midline glioma (DMG), also known as diffuse intrinsic pontine glioma (DIPG), primarily affects children, usually between the ages of 5 and 7. [88] The median survival time with DIPG is under 12 months. [89] Surgery to attempt tumour removal is usually not possible or advisable for pontine gliomas. By their very nature, these tumours invade diffusely throughout the brain stem, growing between normal nerve cells. Aggressive surgery would cause severe damage to neural structures vital for arm and leg movement, eye movement, swallowing, breathing, and even consciousness. [90] [91] [ unreliable medical source? ] Trials of drug candidates have been unsuccessful. [92] The disease is primarily treated with radiation therapy alone.[ medical citation needed ]
Patients with glioma carrying mutations in either IDH1 or IDH2 have a relatively favorable survival, compared with patients with glioma with wild-type IDH1/2 genes. In WHO grade III glioma, IDH1/2-mutated glioma have a median prognosis of ~3.5 years, whereas IDH1/2 wild-type glioma perform poor with a median overall survival of c. 1.5 years. [42] [93]
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant (cancerous) tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secondary tumors, which most commonly have spread from tumors located outside the brain, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the size of the tumor and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with vision, vomiting and mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness.
Oligodendrogliomas are a type of glioma that are believed to originate from the oligodendrocytes of the brain or from a glial precursor cell. They occur primarily in adults but are also found in children.
Glioblastoma, previously known as glioblastoma multiforme (GBM), is the most aggressive and most common type of cancer that originates in the brain, and has a very poor prognosis for survival. Initial signs and symptoms of glioblastoma are nonspecific. They may include headaches, personality changes, nausea, and symptoms similar to those of a stroke. Symptoms often worsen rapidly and may progress to unconsciousness.
Astrocytoma is a type of brain tumor. Astrocytomas originate from a specific kind of star-shaped glial cell in the cerebrum called an astrocyte. This type of tumor does not usually spread outside the brain and spinal cord and it does not usually affect other organs. After glioblastomas, astrocytomas are the second most common glioma and can occur in most parts of the brain and occasionally in the spinal cord.
Isocitrate dehydrogenase (IDH) (EC 1.1.1.42) and (EC 1.1.1.41) is an enzyme that catalyzes the oxidative decarboxylation of isocitrate, producing alpha-ketoglutarate (α-ketoglutarate) and CO2. This is a two-step process, which involves oxidation of isocitrate (a secondary alcohol) to oxalosuccinate (a ketone), followed by the decarboxylation of the carboxyl group beta to the ketone, forming alpha-ketoglutarate. In humans, IDH exists in three isoforms: IDH3 catalyzes the third step of the citric acid cycle while converting NAD+ to NADH in the mitochondria. The isoforms IDH1 and IDH2 catalyze the same reaction outside the context of the citric acid cycle and use NADP+ as a cofactor instead of NAD+. They localize to the cytosol as well as the mitochondrion and peroxisome.
Pilocytic astrocytoma is a brain tumor that occurs most commonly in children and young adults. They usually arise in the cerebellum, near the brainstem, in the hypothalamic region, or the optic chiasm, but they may occur in any area where astrocytes are present, including the cerebral hemispheres and the spinal cord. These tumors are usually slow growing and benign, corresponding to WHO malignancy grade 1.
Cilengitide is a molecule designed and synthesized at the Technical University Munich in collaboration with Merck KGaA in Darmstadt. It is based on the cyclic peptide cyclo(-RGDfV-), which is selective for αv integrins, which are important in angiogenesis, and other aspects of tumor biology. Hence, it is under investigation for the treatment of glioblastoma, where it may act by inhibiting angiogenesis, and influencing tumor invasion and proliferation.
Methylated-DNA--protein-cysteine methyltransferase(MGMT), also known as O6-alkylguanine DNA alkyltransferaseAGT, is a protein that in humans is encoded by the MGMT gene. MGMT is crucial for genome stability. It repairs the naturally occurring mutagenic DNA lesion O6-methylguanine back to guanine and prevents mismatch and errors during DNA replication and transcription. Accordingly, loss of MGMT increases the carcinogenic risk in mice after exposure to alkylating agents. The two bacterial isozymes are Ada and Ogt.
Gliosarcoma is a rare type of glioma, a cancer of the brain that comes from glial, or supportive, brain cells, as opposed to the neural brain cells. Gliosarcoma is a malignant cancer, and is defined as a glioblastoma consisting of gliomatous and sarcomatous components. Primary gliosarcoma (PGS) is classified as a grade IV tumor and a subtype of glioblastoma multiforme in the 2007 World Health Organization classification system (GBM). Because of a lack of specific and clear diagnostic criteria, the word "gliosarcoma" was frequently used to refer to glial tumours with mesenchymal properties, such as the ability to make collagen and reticulin.
A brainstem glioma is a cancerous glioma tumor in the brainstem. Around 75% are diagnosed in children and young adults under the age of twenty, but have been known to affect older adults as well. Brainstem gliomas start in the brain or spinal cord tissue and typically spread throughout the nervous system.
The giant-cell glioblastoma is a histological variant of glioblastoma, presenting a prevalence of bizarre, multinucleated giant cells.
Anaplastic astrocytoma is a rare WHO grade III type of astrocytoma, which is a type of cancer of the brain. In the United States, the annual incidence rate for anaplastic astrocytoma is 0.44 per 100,000 people.
Temozolomide, sold under the brand name Temodar among others, is an anticancer medication used to treat brain tumors such as glioblastoma and anaplastic astrocytoma. It is taken by mouth or via intravenous infusion.
Neutron capture therapy (NCT) is a type of radiotherapy for treating locally invasive malignant tumors such as primary brain tumors, recurrent cancers of the head and neck region, and cutaneous and extracutaneous melanomas. It is a two-step process: first, the patient is injected with a tumor-localizing drug containing the stable isotope boron-10 (10B), which has a high propensity to capture low energy "thermal" neutrons. The neutron cross section of 10B is 1,000 times more than that of other elements, such as nitrogen, hydrogen, or oxygen, that occur in tissue. In the second step, the patient is radiated with epithermal neutrons, the sources of which in the past have been nuclear reactors and now are accelerators that produce higher energy epithermal neutrons. After losing energy as they penetrate tissue, the resultant low energy "thermal" neutrons are captured by the 10B atoms. The resulting decay reaction yields high-energy alpha particles that kill the cancer cells that have taken up enough 10B.
Isocitrate dehydrogenase 1 (NADP+), soluble is an enzyme that in humans is encoded by the IDH1 gene on chromosome 2. Isocitrate dehydrogenases catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. These enzymes belong to two distinct subclasses, one of which uses NAD+ as the electron acceptor and the other NADP+. Five isocitrate dehydrogenases have been reported: three NAD+-dependent isocitrate dehydrogenases, which localize to the mitochondrial matrix, and two NADP+-dependent isocitrate dehydrogenases, one of which is mitochondrial and the other predominantly cytosolic. Each NADP+-dependent isozyme is a homodimer. The protein encoded by this gene is the NADP+-dependent isocitrate dehydrogenase found in the cytoplasm and peroxisomes. It contains the PTS-1 peroxisomal targeting signal sequence. The presence of this enzyme in peroxisomes suggests roles in the regeneration of NADPH for intraperoxisomal reductions, such as the conversion of 2,4-dienoyl-CoAs to 3-enoyl-CoAs, as well as in peroxisomal reactions that consume 2-oxoglutarate, namely the alpha-hydroxylation of phytanic acid. The cytoplasmic enzyme serves a significant role in cytoplasmic NADPH production. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Sep 2013]
Alternating electric field therapy, sometimes called tumor treating fields (TTFields), is a type of electromagnetic field therapy using low-intensity, intermediate frequency electrical fields to treat cancer. TTFields disrupt cell division by disrupting dipole alignment and inducing dielectrophoresis of critical molecules and organelles during mitosis. These anti-mitotic effects lead to cell death, slowing cancer growth. A TTField-treatment device manufactured by the Israeli company Novocure is approved in the United States and Europe for the treatment of newly diagnosed and recurrent glioblastoma, malignant pleural mesothelioma (MPM), and is undergoing clinical trials for several other tumor types. Despite earning regulatory approval, the efficacy of this technology remains controversial among medical experts.
Diffuse midline glioma, H3 K27-altered (DMG) is a fatal tumour that arises in midline structures of the brain, most commonly the brainstem, thalamus and spinal cord. When located in the pons it is also known as diffuse intrinsic pontine glioma (DIPG).
Matthias Preusser is an Austrian oncologist and Professor of Medical Oncology as well as Head of the Clinical Division of Oncology at the Medical University of Vienna. He is known for his work on neurooncology, Molecular Therapy targets and biomarkers and immunotherapy of cancer.
Anaplastic oligodendroglioma is a neuroepithelial tumor which is believed to originate from oligodendrocytes, a cell type of the glia. In the World Health Organization (WHO) classification of brain tumors, anaplastic oligodendrogliomas are classified as grade III. In the course of the disease, it can degenerate into highly malignant oligodendroglioma, grade IV. The vast majority of oligodendrogliomas occur sporadically, without a confirmed cause and without inheritance within a family.
Diffuse hemispheric glioma, H3G34 mutant (DHG) is a rare, high-grade, infiltrative WHO grade 4 brain tumor most often found in adolescents and young adults. The majority are found in the frontal, parietal, and temporal lobes.
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