While A549 cells — an adenocarcinoma cell line thought to be derived from AEC2s — lack surfactant protein or NKX2-1 gene expression and thus do not recapitulate normal AEC2 physiology, we were surprised to find that A549 cells do model many of the intracellular features of our iAEC2 mutant ABCA3 model system. The gene discussed is NKX2-1; the disease is adenocarcinoma.