Why do we have brain cancer?

You knew I'd ask this sooner or later.

The causes of brain cancer are unknown. However, certain factors increase a person's risk of developing it. Compare your answers with mine. Maybe we'll find a common link.

Being male.

This doesn't work for me because I'm female.

Being caucasian.

Yes, I am white.

Being younger than 8 or older than 70.

Doesn't apply to me--I was diagnosed at 29.

Family history.

Grandfather did have a partial stroke and found he had a brain tumor at 88, but the pathology was never determined. (And this was learned about two years after my diagnosis.) 2015 Update: My dad was diagnosed with and died from glioblastoma.

Exposure to:

• Radiation. Doesn't apply.

• Formaldehyde. Doesn't apply.

• Vinyl chloride. Doesn't apply.

• Acrylonitrile. Doesn't apply.

Then there are the theorized causes that haven't been proven.

Cell phones.

I got my first cell phone in 2005. I was a later bloomer.

Head injury.

In eighth grade I was hit by a truck while in a crosswalk, lost consciousness and sustained a concussion (along with other injuries).

Using these factors, we can say I possibly have brain cancer because I am a white person who sustained a head injury, and now uses a cell phone, with a grandfather who also had a brain tumor of unknown origin.

I think I am more confused now than I was before. How do you compare?