A549 is an adenocarcinomic cell line that was established in 1972 from the lung tissue of a 58-year-old Caucasian male. A549 is categorized as a non-small-cell lung carcinoma, which is more common yet less aggressive than small cell lung carcinoma. A549 cells are hypotriploid, have a modal chromosome number of 66, and exhibit an epithelial-like morphology with adherent cultural properties. A549 cells are suitable transfection hosts for in vivo and in vitro models, and an A549 Transfection Reagent can be found at Altogen Biosystems . An A549 xenograft model drawn from an in vivo transfection can be found here . The A549 cell line widely serves as a model for the study of not only lung adenocarcinoma, but also respiratory infections, asbestos exposure, and viral infections stemming from asthma.