Submitted by SnooRegrets2663 t3_ylxnkc in askscience
Let's say that a person who didn't know they had a malignant tumour gave a blood donation which happened to contain cancer cells. Ignoring the processes of cleaning and keeping the blood fresh, could it cause cancer if it were transfused into another patient or would white blood cells just destroy it?
Not really. This article does a decent job of discussing the topic. In short, it is theoretically possible that certain cancers could be "transmissible," but the subject isn't very well understood. However, a big study of medical registry data in Scandinavia found no statistically significant increased risk of cancer among people who had received a blood transfusion from someone who developed cancer.
Key takeaway is here:
>The researchers identified 978 cases of cancer among all the blood recipients but after statistical analysis they found no excess risk of cancer overall among individuals who had received one or more blood products from a precancerous blood donor. The relative risk was not substantially affected by sex age, calendar period, or number of transfusions. What is more, there was no excess risk when patients who received blood from people with cancers at sites that are thought to have the highest risk of metastasising through blood---the lung, liver, skeleton, and central nervous system---were combined.
Similar studies in the US have found the same thing: "Results did not imply any concrete association between cancer risk and history of blood transfusion. These findings would help in debunking the myth of increased cancer risk following blood transfusion."
There are cases of transmissible cancers in animals, but these are mostly in highly bottlenecked populations with low genetic diversity (i.e., the cancer is less likely to seem foreign to a new host).
The few cases in humans involve a degree of immunosuppression.
So like the other poster said, it's not impossible, but it's pretty unlikely.
Yeah sounds about right, there are after all many different factors which can increase the risk, so its pretty much mitigated even if it were the case.
I don't know about blood, but there are only three known cases of transmissible cancer. Probably the most famous one is the CTVT. It's sometimes wrongly called by the press "immortal dog". https://en.m.wikipedia.org/wiki/Canine_transmissible_venereal_tumor
You say blood transfusion. This doesn't necessarily mean a cancer cell that is being past.
There is a programmable virus that has the ability to start cancer on target tissue (that is you can program it to target a specific type of tissue, like lung for example). I don't remember the name, but I think it was first discovered on chicks. Now, I'm thinking that if one person somehow had that or similar type of virus capable of starting cancer, and they had a blood transfusion...
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Rous sarcoma virus?
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Newcastle Disease Virus?
How about cancer transmission from a tapewrom to a human to give you some nightmares?
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Man, I forgot about that one. Switching off the body's firewall settings sure does cause weird and awful things to happen sometimes...
Cervical cancer is transmitted by a virus that transforms the human cells. The cancer itself isn't what's transmitted. The cancer-causing agent is transmitted.
Is it possible to target cancer cells? Give cancer cancer?
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This shouldn't be the one, cuz wikipedia says that this one doesn't cause cancer but on the contrary, it prefers infecting and killing cancer cells. So, it's the vice versa situation. It's also interesting though. I mean, does it really work? And if so, then why don't they use it more often instead of chemotherapy? Guess even they don't know if it works or not. Hope they make it useful somehow.
I think cancer cells are making themselves more cancer already, I mean, mutating more, getting broken more, getting out of control more, spreading more... What you need to do is to either fix them, or kill them. Killing sounds easier.
But thinking about it now, perhaps if you could specifically find and broke them to the point which they can't function at all anymore, that might work too. But still, if you could find them, why not just kill them?
The Newcastle virus stuff which /u/Med_vs_Pretty_Huge has mentioned above sounds like something you may be interested in. In wikipedia it says that it prefers infecting and killing cancer cells more than they do ordinary cells, somehow.
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Well I just saw that others made this comment too, so consider this redundant.
There are actually transmittable (they can spread ok their own) types of cancer, however only three are know to occur in mammals (dogs, tasmanian devils and syrian hamsters).
https://en.wikipedia.org/wiki/Clonally_transmissible_cancer?wprov=sfla1
The transmission of facial tumor from Tasmanian devil to Tasmanian devil comes to mind:
If the recipient is immunosuppressed, yes. Such as an organ donor recipient who takes immune suppressing drugs in order to not reject the donor organ.
Under normal circumstances, your immune system will see the cancer as someone else's cells and mark it for destruction. In the 20th century before medical ethics was really a thing, there were experiments done on prisoners where tumours were transplanted from one person to another. The immune system identified the tumours as foreign, and they became necrotic. Your body is also frequently identifying potential tumours from your own mutated cells and destroying them, when some dysregulated, immortal cells avoid detection by the immune system, then you can send up with a tumour or a cancer.
You said a programmable virus that you can program to target a specific tissue that was discovered in chicks. NDV is a virus in chickens that can be programmed to do that.
Yes, NDV (and other viral vector-based) cancer therapies are in development. They are not ready for primetime because it's a delicate balance between a viral vector that won't be immediately cleared by the immune system but also won't cause a severe infection and then you need a mechanism of action against the tumor that the virus can encode that isn't toxic to the person while also being effective at killing cancer cells. Also, unlike drugs, these viruses can potentially mutate which is another safety concern.
One of the main issues with cancer, is that it is your own cells that are going haywire, so your immune system isn’t going to attack yourself and the cells replicate unchecked. If you introduce a cancer cell from another body, it will be recognized as foreign and initiate an immune response. It would be far more difficult to grow as it would be a foreign cell.
I read of a man getting organ Transplant from woman who had survived cancer many years before. He developed cancer in the same organ she had it in, not the transplanted organ. Her body had developed immunity to recognize and kill her cancer cells. The recipient didn't have them and was taking immunosuppressive drugs for the Transplant. Thus he didn't have any defense. I have read (Dr. Thomas sigfried) that inserting a cell mitochondria from a cancer cell into a normal cell creates a cancer cell. Inserting a ell nucleus from cancer cell into normal cell does not create a cancer cell. Which make cancer a cellular metabolism disease.
One of the theory to explain why large animals like whales have less cancers than smaller ones is that cancerous tumors can themselves get cancer and die off. Evolution is also a possible explanation. Kurzgesagt made a video about that.
There hasn't been reports of cancer transfer through blood transfusions (very rate and if any) but there are reports from solid organ transplants.
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The first thing is what exactly is cancer. Cancer is still a mystery to scientistic/medical community.
In simplest terms cancer is your own cells running amok. Obviously there is a "switch" that as your organs form it knows to stop dividing. For example, imagine if your heart cells, in utero forgets to "turn" off and keeps dividing. Somehow, it knows once it forms a "heart" it stops dividing.
Cancer cells do not know how to turn itself off. It keeps dividing and growing.
So to answer your question, can a transfusion spread cancer to another person. It is the so call "switch" that has become elusive in science. You would need to transfer whatever triggers the cancer cell from the donor body into the host body and the host cells would then need to incorporate it.
NFκB is an important signaling pathway that is involved extensively in cancer development and progression. The protein molecule has been studied at least over a decade. But simply blocking it does not necessarily prevent/treat cancer but research is ongoing.
However, we also know that some viruses can "spread" cancer like HPV. The human papilloma virus, which is associated with cervical and head and neck cancers, encodes a protein, E6, that promotes degradation of p53, while another viral protein, E7, inactivates pRB and CKIs, among other effects (Munger and Howley 2002). However, HPV is spread person to person through contact.
Hepatitis B can cause liver cancer and is spread through blood.
There are reports of cancer transmission from solid organ transplants.
the canid cancer that is the last living descendant of the north american dogs
Also not blood transfer, but there are cases that children acquire cancer from their mothers during birth.
Here is one example and the mention other cases in this article as well: https://www.upi.com/Health_News/2021/01/07/Women-can-transmit-cancer-to-infants-in-childbirth-reports-suggest/7101609975411/
>these are mostly in highly bottlenecked populations with low genetic diversity
Don't humans have remarkably low genetic diversity though? Especially outside of Africa.
Turns out the firewall is there for a reason who knew! Xd it's always terrifying and fascinating when one of the many complicated and interwoven systems of our body breaks down. It's so cool to me how widespread the effects can be, even for seemingly minor changes (doesn't apply here but still)
I see. Thank you for the explanation.
I remember people talking about personalized drugs for cancer in past, which wouldn't have the problems of infection or immune response, but I'm guessing that would be extremely expensive.
Perhaps the researchers can find a way to target all sorts of cancer cells, and somehow develop a vaccine, so the immune system itself can cleanse any possible cancer. They can't even find a general vaccine for flu though. So, I don't have much hope. May be if they could target cells with something other than their outer surface... But they must have already been thinking about it. Hard stuff.
Your intuition and comparison to flu is correct. The genome of flu is miniscule and yet it mutates enough every year to render prior vaccines and infections less effective. "Cancer" is hundreds or thousands of different diseases with different mutations etc. It will be a marvel when market approval comes for a vaccine that eliminates a single type of cancer (e.g. a melanoma "vaccine"). A universal cancer vaccine will likely never happen. It's like having a single vaccine for every virus and bacteria on the planet.
Internal antigens are certainly investigated but yes, they are harder because they will only be exposed to the immune system in small pieces on MHC class 1 molecules and thus it can be even harder to differentiate tumor from normal. The checkpoint inhibitors enhance the immune system's ability to do this to an extent but they are non-specific boosters of immune function and can result in life-threatening autoimmune disease.
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