Are "a549" lung cancer cells a particular type or sub-type of lung cancer, or is this a generic code for lung cancer cells of all types?

Cell culture: A549 are cells that were isolated a long time ago from a lung cancer and maintained in culture for experimental purposes as a model for type II alveolar lining cells

Long cell culture: This was started in 1972 and is still going. It's not really so much about cancer as it's a useful line of cells that grows well. It just happens to be from a lung cancer but is really about human cells. The number indicates a cell line, and has nothing really to do with lung cancer otherwise.

Research cell line: A549 cells are human lung adenocarcinoma cells.The A549 cell line was developed in 1972 through the culturing of cancerous lung tissue. They are responsible for the diffusion of substances, such as water and electrolytes, across the alveoli of lungs. In addition these cells are able to synthesize lecithin and contain high level of unsaturated fatty acids. The A549 cell line is widely used as an in vitro model for drug metabolism and as a transfection host.