Glioblastoma is the most common and aggressive kind of Primary Brain tumor. It is also known as grade 4 astrocytoma. Its treatment includes Chemotherapy, radiotherapy and surgery. But all of these are not actual cure, they are only methods of increasing survival rate. No scientific theory has proved that it is a hereditary disease. So if your parents have it, you should not be worried about having it.
No but it could have been something they were both exposed too,,,
My father and his grandfather both died from this and my father did not live near his father as his parents were divorced so I know that this wasn't environmental