Brain Tumors Flashcards
How does cancer start?
- Cancer begins with a precancerous genetic change (a benign growth), then additional genetic changes occur and it progresses to cancerous cell growth
- Once a cellular growth has become malignant, the cells are invasive
- They can become metastatic and invade blood vessels and different tissues to grow and proliferate there
What is angiogenesis in cancer?
Cancer cells secrete factors that stimulate the growth of blood vessels to feed the growing cancer cells
What are oncogenes?
Gene that can cause cancer. (too many GO signals)
What are tumor suppressors?
Usually they stop cells at checkpoints but a mutation in this gene can remove the stop sign and allow a mutated/damaged cell to keep dividing.
What is a proto-oncogene?
Normal growth factor receptor before it becomes an oncogene.
What is the 2 hit model?
You need mutations in both alleles of a tumor suppressor or oncogene to cause a cancerous cell. You can have a predisposition to cancer if you inherit one mutation. You can’t inherit 2 because it kills the embryo.
What are the types of primary brain tumors?
Meningioma, Ependymoma, Medullaoblastoma, Gliomas = Astrocytomas, Glioblastomas, & Oligodendrogliomas
What are the symptoms of gliomas?
Headache, nausea, seizures, changes in personality, memory loss, impaired concentration, vision changes, muscle weakness
What causes a medulloblastoma?
They arise from neural progenitor cells in the cerebellum, and 5% of patients carry a germ-line mutation in patched-1, a gene involved in the hedgehog signaling pathway that is important in embryological development.
What are the 4 features to look for when grading primary brain cancers?
- Pleomorphism = odd cells
- Mitosis
- Necrosis
- Neovascularization
What are treatment options for brain tumors?
- Surgery
- Radiation
- Chemotherapy
What are the treatments for tending to the symptoms of brain tumors?
- Glucocorticoids: decrease the volume of edema surrounding brain tumors and improve neurological function
- Anticonvulsants: reduce seizures
Where are neuronal stem cells found in the adult brain?
Subventricular zone (SVZ) & Subgranular zone (SGZ) of the dentate gyrus
What do gliomas and stem cells have in common?
- Self renewal
- Intrinsic drive to migrate
- Shared routes of migration along nerve tracts or blood vessels and through narrow extracellular spaces in brain
How do gliomas metastasize?
Gliomas are highly invasive and metastasize through active migration rather than just via the blood. They displace the astrocytic endfeet which breaches the BBB
