Medulloblastoma is a type of brain cancer. It most often affects children. But in rare cases, it can happen in adults. These tumors start in the cerebellum, near the back of the brain. The cerebellum controls balance and coordination.
Any tumor in the brain may press against a part of your brain and cause problems.
Medulloblastoma is a primary brain tumor. That means it starts in brain cells. It hasn't spread to the brain from somewhere else in the body. This type of tumor may spread (metastasize) within the brain and spinal cord. In rare cases it can spread to the bone marrow, lungs, or other parts of the body. The outlook for tumors that have spread tends to be worse than for tumors that stay in one place.
These are fairly fast-growing tumors. They are grouped into four molecular subtypes, but this classification is evolving:
- WNT. This is the least common subtype. The cancer cells have mutations of CTNNB1 encoding b-catenin.
- SHH (sonic hedgehog). These cells have SHH receptor PTCH mutations or SHH inhibitor SUFU mutations. GLI1 and GLI2 amplifications are also possible.
- Group 3. The cells have MYC amplification and gene expression of photorecepto/GABAergic.
- Group 4. This is the most common sub-group. CDK6 and MYCN are amplified. Neuronal/glutamatergic gene expression is seen.
Talk with your provider if you'd like to learn more about the subgroup you or your child are in and what the genetics mean for your treatment and outlook.