Dexamethasone, a synthetic glucocorticoid, activates GR signaling, which subsequently induces the expression of CDKN1C/p57, leading to G1/S-phase cell cycle arrest, specifically in Liver Kinase B1 (LKB1)-mutated NSCLC cells, thereby suppressing tumor growth. The gene discussed is STK11; the disease is non-small cell lung carcinoma.