Having been studied extensively over the past few decades, A549 cells have become one of the major players in the lung carcinoma field. With numerous applications in cell signaling studies and cancer oncogene evaluations, A549 xenografts have become prime targets for transfection experiments and related research. The cells are set apart by their ability to synthesize lecithin and their internal environment; a high level of unsaturated fatty acids that contribute to the maintenance of membrane phospholipids in lung epithelial cells. The cell line has been used extensively as an in vitro host capable of receiving nucleic acids and responding effectively in drug metabolism studies.