TTF1 and bronchopulmonary dysplasia: Furthermore, transcription factors binding upstream can also be considered as candidates, including TTF-1 increasing gene expression of ABCA3 with relevance for lung development.57, 58 Although another study could not find any significant associations of TTF-1 variants with BPD,59 a possible connection and thus an importance of this transcription factor for the development of BPD remains.