O.O I don’t know if this has been published in a paper and been peer-reviewed yet, but holy crap!
Can you imagine the wtf moment when the poor technician/grad student/post doc checked the implanted mutant cancer cells for mitochondrial DNA and FOUND DNA where they expected there to be none?
And then the heart stopping moment when the mitochondrial DNA was determined to have come from the surrounding healthy tissue???
I’m no oncologist, so here’s my non-professional take on the significance of this discovery: cancers result when a cell acquires mutations that causes it to stop responding to signals in its environment and instead, allows/encourages it to start dividing. A cell that starts dividing unchecked will form a tumor. As a tumor grows, some cells will slough off and travel via the blood stream to other parts of the body, where it lodges and divides and forms more tumors.
Sometimes, surgeons can “catch” a cancer by removing a tumor before cells start to slough off. Sometimes, because the tumorous cells are in an inaccessible place or because the tumor has already started sloughing off cells, oncologists will use chemotherapy or radiotherapy to kill the cancerous cells. Sometimes, after a round of treatment, cancer returns – and if this happens, it is much harder to kill – because these new cancer cells have acquired mutations that allow it to survive particular chemo/radiotherapy. Think of superbugs (MRSA, etc) that result from the overuse and abuse of antibiotics – if you don’t finish your round of antibiotics and therefore don’t wipe out all of the bacteria in you that is making you sick, then the bacteria that have survived will continue to reproduce and your infection will come back. Or, if this resistant bacteria now makes its way out of you, it can encounter other bacteria and give DNA to these other bacteria that also confer antibiotic resistance properties to them. Hence, super bugs.Or, in the context of cancer, cancer that kills.
Now, we know that cancerous cells have a lot of mutations in them – when we sequence the DNA of individual cells in a tumor, we can see distinct populations and lineages of acquired mutations – and the more varied the mutations in a population of cancerous cells, the more difficult it will be to eradicate that cancer (this is my conjecture, cancer researcher FB friends pls feel free to jump in). We know that bacteria can exchange DNA. What we did NOT know was that cancer cells may also be able to do this, which is what this article is showing. This contributes to our understanding of why some cancers are so deadly and if we can understand how or why they have this property – do normal mammalian cells have this property? – we may be able to short circuit it and prevent cancer cells from “acquiring beneficial DNA” that will help them grow… or alternatively, we may be able to sabotage it by inducing cancer cells to take up normal/cancer-repressing DNA to compensate for cancer-encouraging mutations.