NKX2-1 and adenocarcinoma: Although Nkx2-1+/– mice do not develop spontaneous lung tumors, overexpression of K-RasG12D in Nkx2-1+/– mouse lung results in a larger number of malignant lung tumors (with greater volumes) than in wild-type mice.53 Snyder et al.54 also demonstrated that simultaneous KrasG12D expression and Nkx2-1 deletion in lungs (KrasLSL-G12D;Nkx2-1−/−) results in early onset malignant adenocarcinoma.