Cell line
A population of cells, usually taken from a tumour decades ago, that keeps dividing indefinitely in the laboratory. The workhorse of cancer research: cheap, fast and infinitely reproducible, but a distant cousin of a real tumour.
HeLa, from Henrietta Lacks's cervical cancer in 1951, was the first, and around a thousand cancer cell lines are now in common use, each with its genome, drug sensitivities and gene dependencies catalogued in resources such as the Cancer Cell Line Encyclopedia and DepMap. They are how targets are validated, how CRISPR screens find vulnerabilities, and how drugs are first tested, and they are also the factories that produce therapeutic antibodies and the source material of some off-the-shelf cell therapies. Decades in plastic select for fast growth and remove the tumour's three-dimensional structure, blood supply and immune environment, which is why organoids and patient-derived models were developed.