KIT, also known as proto-oncogene c-Kit or tyrosine-protein kinase Kit or CD117, is a growth factor receptor of the tyrosine kinase subclass III family, normally expressed in a variety of tissue types. Signaling through CD117 plays a role in cell survival, proliferation, and differentiation. Altered forms of this receptor may be associated with some types of cancers. Somatic mutations of KIT in lung adenocarcinoma are relatively rare, reported up to 3.3% of the cases. The predictive and prognostic significance of KIT mutations in lung adenocarcinomas needs further elucidation. Results should be interpreted in conjunction with other laboratory and clinical findings.