What's the relationship between brain cancer and seizures? Do seizures mean brain cancer?

One possible cause of seizures is cancer in the brain, either a primary brain cancer or cancer from another part of the bady that has metastasized to the brain. It is important to tell your doctor if you have a seizure.

It's not helpful because it does not address the issue as why brain cancer causes seizure. What is about the tumor that causes seizures. Location, size, etc. We know that brain cancer is a result usually from metatasis of other cancers like lung, breast, etc. but why seizures was the question asked.