As preclinical proof of concept, drug combinations of clinically advanced HSP90 inhibitors32 with trametinib or MTA potently suppressed cancer cell viability and tumor growth in various tumor models, including a PDX model of KRAS-mutant lung adenocarcinoma, validating a long-sought and readily implemented therapy for the most devastating subset of lung cancer. Here, KRAS is linked to lung adenocarcinoma.