Due to these challenges, prior studies have relied on genetically engineered ABCA3 overexpression models in cancer or immortalized cell lines, such as the human embryonic kidney 293 cell line (HEK293) or the lung adenocarcinoma–derived A549 cell line (18–27), neither of which express surfactant genes, produce functional surfactant, or express the NKX2-1–driven gene regulatory network that defines all known endogenous lung epithelia in vivo (28–30). Here, ABCA3 is linked to cancer.