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What is lower grade glioma?
Lower grade glioma is a type of cancer that develops in the glial cells of the brain. Glial cells support the brain’s nerve cells and keep them healthy. Tumors are classified into grades I, II, III or IV based on standards set by the World Health Organization. TCGA is including grades II and III in this specific study, as opposed to the more common and higher grade brain tumor, glioblastoma multiforme, which was studied in a separate project. Regardless of grade, as the tumor grows it compresses the normal brain tissue, frequently causing disabling or fatal effects.1 In 2010, more than 22,000 Americans were estimated to have been diagnosed and 13,140 were estimated to have died from brain and other cancers of the nervous system.2 View additional information on lower grade glioma.
What have The Cancer Genome Atlas (TCGA) researchers learned about lower grade glioma?
TCGA researchers have:
- Described mutations and chromosomal alterations that define three lower grade glioma subtypes with distinct clinical outcomes: IDH mutant and 1p/19q co-deletion; IDH mutant without 1p/19q co-deletion; and those without IDH mutation (IDH Wild-Type)
- The chromosomal co-deletion 1p19q, which consists of the deletion of a short arm of chromosome 1 and longer arm of chromosome 19, was associated with the most favorable prognosis
- The 1p/19q abnormality frequently paired with mutations in IDH1 and IDH2, mutations in the enzyme isocitrate dehydrogenase that lead to abnormal enzyme activity, hypermethylation, and deviant gene expression
- The combination of 1p19q co-deletion and IDH mutation was associated with the most favorable prognosis
- Patients without mutations in the IDH genes experienced the poorest outcomes
- Illuminated the relationship between subtypes of lower grade glioma and glioblastoma multiforme (GBM)
- The lower grade glioma subtype without IDH mutations demonstrated very similar genomic markers and clinical outcomes to GBMs, indicating that this subtype of lower grade glioma may be a precursor to its more aggressive counterpart, GBM
- Identified molecular signatures and subtypes that may inform the classification, diagnosis, and treatment of lower grade gliomas
- Lower grade gliomas without IDH mutations may benefit from treatment with protocols adapted from current GBM treatments
- Recently developed targeted therapies that could curb the aberrant activity of IDH1/2 proteins in lower grade glioma are currently being tested for efficacy and safety in clinical trials
Where can I find more information about the TCGA Research Network’s studies or studies using TCGA data?
Where can I find clinical trials to treat brain tumors that are supported by the National Cancer Institute (NCI)?
View a list of NCI-supported brain tumor clinical trials that are now accepting patients.
1The American Cancer Society. (20 June 2011). Brain and Spinal Cord Tumors in Adults. Retrieved from http://www.cancer.org/Cancer/BrainCNSTumorsinAdults/DetailedGuide/brain-and-spinal-cord-tumors-in-adults-what-are-brain-spinal-tumors
2American Cancer Society: Cancer Facts and Figures 2010. Atlanta, GA: American Cancer Society, 2010.