query: Does glioblastoma multiforme cause tumors?
passage: Glioblastoma
The cause of most cases is unclear.[2] Uncommon risk factors include genetic disorders such as neurofibromatosis and Li–Fraumeni syndrome, and previous radiation therapy.[2][3] Glioblastomas represent 15% of brain tumors.[1] They can either start from normal brain cells or develop from an existing low-grade astrocytoma.[6] The diagnosis typically is made by a combination of CT scan, MRI scan, and tissue biopsy.[1]
passage: Glioblastoma
Research has been done to see if consumption of cured meat is a risk factor. No risk had been confirmed as of 2013.[77] Similarly, exposure to radiation during medical imaging, formaldehyde, and residential electromagnetic fields, such as from cell phones and electrical wiring within homes, have been studied as risk factors. As of 2015, they had not been shown to cause GBM.[12][78][79] However, a meta-analysis published in 2007, found a correlation between increased incidence of GBM and use of a cell phone for longer than 10 years, especially among those who always held the phone on one side of their head.[12]