STK11 and neoplasm: SIK1/3 are key effectors of LKB1-mediated tumor suppression in lung cancer, and Sik-targeted tumors also exhibit lower expression of ATII markers relative to tumors driven by oncogenic KRAS alone, suggesting that SIKs may mediate the activation of the C/EBP-driven ATII differentiation program downstream of LKB1 (Fig. 6h and Supplementary Fig. 11g)35,36.