- Developmental cooperation of leukemia inhibitory factor and insulin-like growth factor I in mice is tissue-specific and essential for lung maturation involving the transcription factors Sp3 and TTF-1. Pichel, J.G., Fernández-Moreno, C., Vicario-Abejón, C., Testillano, P.S., Patterson, P.H., de Pablo, F. Mech. Dev. (2003)