STAT3 and Mungan syndrome: Signal transducer and activator of transcription 3 (STAT3) belongs to the STATs family, and may be the most intimately linked to tumorigenesis.1 Activation of STAT3 is initiated by phosphorylation, followed by dimerization and translocation into the nucleus to regulate transcription of target genes.2 As a master transcription factor and also an oncogene protein, STAT3 is transiently activated in normal cell, but is constitutively activated in malignant gliomas (MGs).