After three months the tumor was removed and placed in culture. At passage 3, these cells were re-injected into nude mice.
NL20 cells at passage 183 were inoculated into nude mice and a small slowly growing subcutaneous tumor developed from a minor clone in this otherwise stable cell line.
One of the resulting tumors was dissociated, placed in culture and designated NL20-TA. This cell line (ATCC CRL-2504)
remains tumorigenic up to at least passage 250.
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