GTF2B encodes transcription factor IIB (TFIIB), one of the ubiquitous general transcription factors essential for transcription initiation by RNA polymerase II (Pol II). Localizing to the nucleus, TFIIB forms a complex with transcription factors IID and IIA and serves as a critical bridge between TFIID-the factor that initially recognizes the promoter-and the Pol II machinery, thereby enabling pre-initiation complex (PIC) assembly and Pol II recruitment to promoter DNA. Beyond this core architectural role, TFIIB is subject to regulatory acetylation and autoacetylation, and emerging evidence links its dysregulation to pathological states, including potential contributions to proliferation in hepatocellular carcinoma and tumor phenotypes in growth hormone-secreting pituitary adenomas.