Another study of study of tumors caused by cellphones has produced a conclusion that suggests an increased incidence of a rare kind of tumor called a glioma on the side of the head where the cellphone is used most. The study was done in Finland with people that had the rare kind of tumor, and their cellphone usage was compared to those who did not have tumors. Long term users of cellphones (more than ten years) had a higher risk of developing the tumor.