NKX2-1 and lung adenocarcinoma: We have previously shown that Nkx2-1 deletion augments ERK activity in KRASG12D-driven lung adenocarcinoma (Snyder et al., 2013), and feedback inhibition of the MAPK pathway is known to be rate-limiting for the growth of KRASG12D-driven tumors in vivo (Shaw et al., 2007).