NKX2-1 and mucinous adenocarcinoma: However, deletion of Nkx2-1 in adult lung does not induce adenoma.53, 54 Therefore, inactivation of Nkx2-1 appears to be involved not only in tumor initiation but also in the transition from adenoma to mucinous adenocarcinoma, although deletion of Nkx2-1 alone does not result in the development of adenoma.54