So my friend told me not 30 minutes ago that her sister has a level 4 astrocytoma. I looked it up and Wikipedia, it's hard to understand it like, technically, but I did learn how dangerous it is. So I guess my question is, does anyone know anything about astrocytomas? Layman terms, please.

To make the thread more relevant, have you or any relatives/friends had cancer before? What kind was it? What was it like?

PS: I've been wondering, how does cancer kill people? I'm guessing there are more ways than one considering how many strands there are (what are the major strands?), but like, what's the most common? Just cell destruction and continuous replication?