A549 cells are adenocarcinomic human alveolar basal epithelial cells. The A549 cell line was initiated from the removal and culturing of cancerous lung tissue in the explanted tumor from 58-year-old male, in 1972. A549 cells is able to synthesize lecithin and contain high level of unsaturated fatty acids, which are important to maintain the membrane phospholipids in cells. A549 cell line are widely used as an in vitro model for a type II pulmonary epithelial cell model for drug metabolism and as a transfection host.