After stratification of the patients according to the diagnosis, we found significantly elevated TGF-β1 serum levels in patients with primary glial tumors (10.84 ± 5.06 ng/mL) compared to the control group (8.06 ± 4.07 ng/mL, p = 0.033, t-test). Here, TGFB1 is linked to glioma.