NKX2-1 and lung carcinoma: While its dual roles in driving lung development and differentiation on the one hand, and lung cancer (often viewed as de-differentiation) on the other seem paradoxical, NKX2-1 fits well into an emerging class of “lineage-survival” oncogenes—often master transcriptional regulators of normal cell lineage that become deregulated in cancers derived from that lineage [12].