Besides, the deletion of TTF-1 seems to induce the phenotype of mucin through the subsequent release of Foxa1/Foxa2, and human lung infiltrating mucinous adenocarcinomas almost always express HNF4A and have a significant connection with negative TTF-1 expression and positive KRAS mutation status [52]. The gene discussed is TTF1; the disease is mucinous adenocarcinoma.