Surfactant proteins B and C (SFTPB and C) are small hydrophobic surfactant proteins that maintain surface tension in alveoli. Both SFTPB and C are regulated by a key factor, transcription termination factor 1 (TTF1), in lung cells (Evers & Grummt 1995). Thyroid transcription factor 1-associated protein 26 (CCDC59 aka TAP26, BR22) (Yang et al. 2003) binds to TTF1 and enhances TTF1-transactivated SFTPB and C promoter activity (Yang et al. 2006).