SMAD2 and central nervous system cancer: previously reported that GCIP physically interacts with oligodendrocyte transcription factor 1 (Oligo 1, a class-II bHLH transcription factor) to disrupt its TGF-β signaling-dependent association with Smad2/3 and that overexpression of GCIP suppresses TGF-β-induced cell growth and cell migration in glioma (40).