Lung Adenocarcinoma With Primary LIMD1-BRAF Fusion Treated With MEK Inhibitor: A Case Report

• The incidence of non–small cell lung cancer with primary BRAF fusions is rare, and no therapeutics are approved to treat these gene alterations. • Herein, we report the first case with advanced lung adenocarcinoma harboring a novel de novo LIMD1-BRAF fusion that benefited from the mitogen-activated protein kinase kinase inhibitor trametinib. • This patient achieved partial response and had progression-free survival of more than 7 months. This observation supports the single use of the mitogen-activated protein kinase kinase inhibitor trametinib on BRAF fusions.