Plasma levels of transforming growth factor-beta 1 before and after removal of low- and high-grade astrocytomas

► Transforming growth factor beta 1 (TGF-β1) were increased in astrocytoma patients. ► The level of TGF-β1 before tumor removal was ⩾2.52 ng/ml astrocytoma was predicted. ► The TGF-β1 level significantly decreased after tumor removal in astrocytoma patients. ► TGF-β1 and tumor volume was correlated in tumor removal high-grade astrocytoma. ► TGF-β1 might be useful as a tumor marker for astrocytoma.