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scrangos t1_iw3z136 wrote

Reply to comment by Chiperoni in How do medical researchers obtain lab animals with diseases like specific forms of cancer which arise spontaneously? Do they raise thousands of apes and hope some eventually develop the disease? by userbrn1

I've been meaning to ask something about this, isn't cancer prone to further mutations? When you try to expand it, wouldn't it end up changing sometimes?

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Suricata_906 t1_iw4gg08 wrote

Yes, that is true, but it takes some rounds of replication . That’s why for studies you would want to freeze a big batch of tumor tissue or cells, take out a vial for to use once and go back for another vial later. Essentially you are minimizing genetic drift for experimental purposes. Not perfect, but then what is?

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scrangos t1_iw4i78s wrote

Yeah that makes sense. Are those immortal cancer cells that have been used for a long time also been drifting genetically? Has there been a track record of how they've changed over time?

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GoblinGeorge t1_iw4t5vs wrote

HeLa cells have been drifting. There are studies that show cells from different labs have genetic differences, but I don't think it's possible to track all the variations in all the different lines. There are just too many different lines at this point.

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Suricata_906 t1_iw53p66 wrote

No track record as far as I know, but everyone assumes they are not as originally isolated. HeLa cells still have the original HPV induced mutations but unspecified other ones. When was a lab worker, the protocol was to use cells like that for maybe 15-20 population doublings, then discontinue.

The ATCC (American Type Culture Collection) is the motherlode for all kinds of cells, from the fairly normal, to things like HeLa that I like to say would grow on walls!

Fun fact. Most cells cultures isolated from normal human tissues have an expiration date called the Hayflick Limit of 50 or so population doublings before they become senescent and won’t divide. immortalizing mutations of various kinds override that.

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corduroy t1_iw6n9ae wrote

Just to add, there's a lot less genetic drift when passaging in vivo as compared to in vitro.

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