TGFB1I1 (transforming growth factor beta 1 induced transcript 1) encodes a coactivator of the androgen receptor, a transcription factor which is activated by androgen and has a key role in male sexual differentiation. The encoded protein is thought to regulate androgen receptor activity and may have a role to play in the treatment of prostate cancer. Multiple transcript variants encoding different isoforms have been found for TGFB1I1.