CREB1 and lung adenocarcinoma: Therefore, the specific mechanism of P4/Org inhibition of lung adenocarcinoma cell growth can be summarized as follows: P4/Org → binding mPRα→activation of Gαi → downregulation of cAMP→inhibition of PKA/CREB and PKA/β‐catenin signaling pathways→inhibition of lung adenocarcinoma cell growth.