EGFR and lung adenocarcinoma: With respect to clinical studies, we are aware of only one small phase II trial encompassing 139 diabetes-free patients with advanced epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma that investigated the therapeutic potential of EGFR tyrosine kinase inhibitors (TKIs) alone and in combination with metformin (NCT03071705) (Arrieta et al., 2019).