TGF-β includes three subtypes; Christian et al. found that TGF-β1 and TGF-β2 mRNAs were strongly expressed in glioblastoma, while TGF-β3 mRNA was increased particularly in astrocytomas and anaplastic astrocytomas [44]. This evidence concerns the gene TGFB1 and astrocytoma (excluding glioblastoma).