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Where do established cell lines often come from?

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tissue culture Tissue culture often requires sterile working conditions and thus is typically performed in a laminar flow cabinet (or tissue culture hood), which circulates filtered air to reduce the risk of culture contamination.

Established cell lines, which are capable of indefinite replication, typically originate from two primary sources:

Tumor biopsies: Many established cell lines are derived directly from tumour tissue collected from patients.1
Mutated primary cells: These lines can also be generated from primary cells that have acquired specific mutations, allowing them to overcome the Hayflick limit—the point at which normal cells typically undergo replicative senescence and stop dividing.1

Unlike primary cultures, which are mortal and excised directly from living organisms via biopsy, established cell lines are immortalized, often through processes involving oncogenic expression or the activation of telomerase, an enzyme that prevents the shortening of telomeres during cell division. Because these cells continue to accumulate mutations over time, researchers must perform authentication to verify the identity of the cell lines used in experiments.21