Would a state be able (with currently available technology) to cause cancer in its enemies, which it can't silence in a different way? (e.g. staged accidents, assassinations, imprisonment)

The answer should include methods that could be used by states, using only currently available technology, or technology that is very likely to be available within a couple of years.

Also, the method doesn't have to always work; 30% chance of causing cancer would still be enough.

As side-note, Hugo Chavez wondered if the US have discovered a way to cause cancer to their enemies:

It would not be strange if they had developed the technology to induce cancer and nobody knew about it until now ... I don't know. I'm just reflecting

[...] Chavez, Fernandez, Paraguay’s Fernando Lugo, Brazil’s Dilma Rousseff and former Brazilian leader Luiz Inacio Lula da Silva have all been diagnosed recently with cancer. All of them are leftists.

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    $\begingroup$ Cancer isn't a quick disease. How quickly were you wanting your victims to be incapacitated? $\endgroup$
    – user10945
    Commented Nov 30, 2016 at 13:17
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    $\begingroup$ @Pete Indeed, though there are some aggressive types of cancer. Also, it doesn't have to induce cancer out of the blue. It could simply increase the growth of existing cancerous cells (since the average human has 50% chance of getting cancer), meaning it wouldn't take that long. And it doesn't have to always be successful. If 1 in 3 attempts succeed at a cost of a few million.. it would still be worth using. "How quickly " - a couple of years. Probably less than 4 would be ideal, because of presidency duration in many countries. $\endgroup$
    – user
    Commented Nov 30, 2016 at 13:53
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    $\begingroup$ The US spent millions on a heart attack gun, seems better than having a way to make someone who is annoying you now get cancer and die years later. $\endgroup$
    – Snowlockk
    Commented Nov 30, 2016 at 13:54
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    $\begingroup$ Sadly, I have experience of glioblastomas being fatal within a year. However, I wouldn't be able to suggest any plausible method of intentionally causing one other than using a "faulty" x-ray machine. I'm also not sure how effective a "weapon" would be given the 30% chance of killing someone in a four year period. You'd assume that whatever threat the person has posed would be possibly negated after that time. $\endgroup$
    – user10945
    Commented Nov 30, 2016 at 14:07
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    $\begingroup$ @Fermi, I was thinking about pre-sensitizing the victim, and then provoking an anaphylactic hyper-reaction, weeks or months later. (With, for instance an uncommon but not unheard of mold spore into the HVAC system.) Happy to chat -- if I can figure out chat here. (I'm new.) $\endgroup$
    – Catalyst
    Commented Nov 30, 2016 at 22:28

5 Answers 5


Low level radiation poisoning

Alexander Litvinenko was killed, probably by the Russian government, by getting him to ingest a significant quantity of radioactive Polonium-210. He did not die of cancer, he died of acute radiation poisoning.

Cancer does not kill fast, so if you are trying to slowly poison/kill your enemies over time (a year or so), this same sort of radiation dosing would be effective. Polonium-210 was hard to detect despite the fact that Polonium is not common (or present) in the human body. It does not give off much gamma radiation (only on 0.001% of all decays); instead giving off alpha particles that caused significant damage to Litvinenko's internal organs while not penetrating to the outside where they could be detected. The medical and police examinations of Litvinenko did not detect the radiation poisoning, it was only when samples were send to the UK's Atomic Weapons Establishment that the Polonium was identified.

A low level dose from certain other radio-nuclides could be even harder to detect. Polonium-210's activity ($\lambda$) is 8.36$\times10^{-8}$ 1/s; that means that $1 - e^{-\lambda} \approx \lambda $ or 8.36$\times10^{-6}$ % of the material decays every second. We can find a radio-nuclide that has a lower activity and is thus harder to detect. It will have to decay by alpha or beta decays so that it is difficult to detect outside of the body when ingested. It will have to also decay to a relatively common isotope so that the daughter nuclide isn't easily detected. If the poisoning element was a common biological element, it would be difficult to chemically separate from materials already in your body.

Possible poisons

Lets look at this list and a chart of nuclides to find some possibilities.

-Sodium 22 has activity of 1.22$\times10^{-8}$ (about 1/8 of polonium) undergoes beta decay, delivers 500 eV x-ray radiation about 0.1% of the time, is the 9th common element in the body, and decays to stable $^{22}$Ne which is not common but is found at 0.138 ppm dissolved in blood. Sodium-22 is hard to detect in sodium form, and doesn't release many gammas, but does release positrons that can cause annihilation events and follow-on gamma release that would be suspicious. It also might lead to suspiciously high dissolved neon levels in the blood. However, I don't know how many doctors would perform gas chromotography of the blood as part of diagnosis of any symptoms.

-Strontium 90 has activity of 1.22$\times10^{-8}$ (about 1/80) of plutonium, undergoes beta decay, releases zero gammas, is the 17th most common element in the body, and decays to $^{90}$Y. This isn't great because Yttrium-90 itself is not stable, and will decay within hours to $^{90}$Zr. This second decay does release gammas, 200-400 keV ones 97% of the time, but 2.3 MeV ones .002% of the time. The high energy gammas will occur at 1/40 the frequency as the already hard to detect Polonium gammas; the lower energy ones are lower energy and harder to detect, but will occur about a thousand times more frequently than polonium. I don't know if this would be net easier or net harder to detect. In any case, Zirconium is rare in the human body and might stand out. An advantage of Strontium is its chemical similarity to Calcium, so the body will naturally try to deposit in in bones, giving a very good chance of causing a particularly debilitating case of myeloma.

-Phosphorous 32 has activity of 8.10$\times10^{-7}$ (about 10 times polomium), undergoes beta decay, delivers zero energy as gamma radiation, is the 6th common element in the body, and decays to stable $^{32}$S. This is the most common isotope of sulfur, and the 8th most common element in the body. Phosporous-32 will act quickly, blurring the line between acute radiation poisoning and cancer. Its energy delivery is 1/10 that of polonium, but it decays 10 times faster so net energy delivery is about the same. This will kill in weeks. It does not release gammas at all. Its decay products are identical to the 8th most common constituent of the body and is therefore all-but impossible to detect.


There are three decent options for poisioning. Keep in mind, this is with a 10 microgram dose, equivalent to the one that killed Litvenenko.

  • Strontium-90 will almost certainly cause deadly bone marrow cancer in a few years, but might be detectable due to its significant low energy gamma activity and decay into the rare element Zirconium.
  • Sodium-22 releases x-rays that are unlikely to be detected, and will cause chronic radiation poisoning in about a year. However, the body may be apt at flushing sodium, limiting the damage; the decay product Neon might be detectable in the blood; and the positron annihilations may or may not be detectable.
  • Phosphorous-32 releases no gammas, is metabolized directly into ATP and DNA for a whole body radiation kill, and has an undetectable decay product. However, this would kill in a matter of days leaving little question that the victim has been poisoned somehow.

Pick your poison, and happy hunting.

  • $\begingroup$ If you want a subtle kill, just use less of the P32. The short half life is a very good thing, almost all of it will be gone by the time they are investigating the cancer. $\endgroup$ Commented Apr 24, 2021 at 2:54

How to induce cancer to someone, with current technology? The answer is so simple, that you will not like it, so please bear with me (because I will not limit myself to answer no. 1):

The answer is: make the target start smoking!

Yep, that easy. And perfectly within reach.

Tobacco inoculates you with up to 70 carcinogens, being the no. 1 avoidable cause of cancer, inducing cancers from the lung, larynx, head and neck, bladder, kidney, esophagus, stomach and colon. However, as you know, even smokers haven't got as nearly as 100% rate of cancer. The percentage is something as 10-30%.

So this just goes to show you how hard it is to induce cancer the way you want. Because cancer is a disease that is caused by mutations on the DNA that will make the cells go haywire and proliferate uncontrollably. But even after the mutation, the cells have lots of mechanisms to heal that mutation, be it DNA repair systems, be it immune responses against the tumor cells.

And carcinogen induces DNA mutations, either directly or indirectly.

This means that a person that is not exposed to a carcinogen may develop cancer, and a person exposed to a carcinogen may not. It's a matter of probability, of likelihood.

To increase the cancer rates to non-negliglible numbers, you would have to opt between two strategies: a) Expose the target to a single, but super-high dose of the carcinogen (e.g. radiation from an atomic bomb) b) Expose the target to low, but continuous / repeated, doses of the carcinogen

Both of these would increase the rate of detection.

So let's see some ways we could do this, with technologies available today... even though none will be as simple and accessible as tobacco.

1) Exposure to chemical carcinogens

This is the easiest way and it doesn't need much sophisticated technologies to achieve.

For example, sneakly cover the air conditioning of the rooms where the target works with a layer of asbestos. This will increase the risk of lung and pleural cancer.

Or taint the meals of the target with known carcinogens. For instance, make them eat only cereals contaminated with the Aspergillus fungus, that produces aflatoxin, that increases the rate of liver cancer.

Or make your own cocktail of chemical carcinogens and put them on the food or air supplies.

Pros: The access to these carcinogens may be extremely simple, depending on the carcinogen.

Cons: The efficacy will be extremely low. You would need to constantly taint the food and air of the target, which would increase the risk of detection.

2) Radiation

This is your prefered method, but I don't think it is feasible. Contrary to what Pete has said, I have no knowledge of solid evidence demonstrating that constant exposure to CT scans (or to radiation produced by CT machines) increase the risk of cancer significantly... if it means doing a semestral or trimestral CT scan.

Even radiotherapy, with significantly higher radiation doses, will not increase this risk with great orders of magnitude, even though radiotherapy is more limited in time and is fine-tuned to reduce the risk of radiation-induced cancer to the max.

But still, you would need very high doses of radiation AND you would need them to be focused on a very concentrated and constant spot in the body. Even today, radioncologists need to make "armors" and "masks" that completely imobilize the patient and need to constantly recallibrate the machine in order to be certain that the beam is always affecting the same area, or else the therapeutic benefit gets compromised.

There is just no way to achieve this on a moving target with current technology, without using such a dose of radiation that would affect all the neighborhood, increasing the chances of detection.

3) Radioisotopes

But there is a way that you can make radiation find your target. Kingledion has beat me to the punch with that. Just make the person ingest substances containing radiation releasing isotopes. They will decay at regular intervals and innoculate a dose of radiation at each interval.

You can concentrate the radiation on a specific organ by binding the radioisotopes to molecules that concentrate on particular regions of the body.

For example, the only place on our body that uses iodine is the thyroid. Doctors use 131 iodine as a means to concentrate radiation on the thyroid.

Another example, doctors use radionuclides bound to a prostate specific antigen on diagnostic PET. This antigen concentrates the radiation on the prostate, making it easier to detect prostatic cancer by measuring the radiation released.

Kingledion mentioned strontium 90, which is analogous to calcium, which would concentrate the radiation on the bone. This would be helpful, because the bone marrow (the place where you produce the blood) is a place with a high celular division rate and therefore, very sensitive to cancer induction (leukemias, etc...)

Cons: Radiation may be detected,as kingledion as mentioned.

4) Immunity

It is true that immunosupression may lead to cancer, because then there will be no immune cells to detect cancer cells and destroy them. However, that level of immunosupression would be hard to induce without extremely high doses of myelotoxics or radiation. Furthermore, it would be easily detected before inducing cancer... because the target would contract many infectious diseases beforehand, that would make him/her see a doctor, which would easily detect the immunosupression with a blood test.

So I don’t think that’s feasible.

5) Epigenetic tampering

We don’t solely depend on genetics. We also depend on epigenetics. Meaning, all the cells in our organism possess the totality of our genetic code. But which genes we express, on which organs and at which situations depend on epigenetics.

Epigenetics means that we may turn on or off a gene, by adding molecule radicals (namely methyl radicals) to the DNA sequence immediately preceding that gene.

So, if a cancer is promoted by a mutated gene, we could epigenetically turn it off. And vice-versa... we could epigenetically turn on genes that would increase the likelihood of cancer.

At this time, we don’t have a way to manipulate epigenetics at our will. Every anticancer epigenetic drug that I know of has failed on clinical trials. But it is not a stretch to believe that this technology will be available in a couple of years.

Cons: You would need to develop this drug on highly specialized laboratories. Either you make a drug that just tampers with all your epigenetic make-up (and so the consequences will be unpredictable)... or you develop a drug that epigenetically focuses just on one gene, but then you will have a problem. Because you will need to make that drug available to the target on a sufficient dose. Since you can’t make physical contact with him, it means you can’t innoculate the drug. So the drug should be able to traverse the digestive system without being digested and be absorbed on a sufficient dose to achieve the effect. I don’t think this is feasible for a stealthy assassination.

6) Addiction

Remember tobacco? Everyone knows that it causes cancer! Yet everyone still does it.

Why? Because amongst the carcinogens you have nicotine, which is also a neurotransmitter that causes a sense of well-being and therefore, addiction.

Processed meat is a carcinogen, but who can live without that yummy hamburger? You just need to have it. Just one won’t make a difference, right? Cancer just happens to the others, right? You can stop whenever you want, right?

Just make sure that you couple your carcinogen with an addictive substance or behavior. Thereby you will ensure that the target will be exposed to the carcinogen on continuous and regular doses. The target will BEG you for the carcinogen.

In fact, the target will make the job for you. They will rationalize everything, everything, to be able to continue their addiction. This is truer if you make the addictive drug have a hangover effect, that will cause depression or fatigue, so the target will no longer be able to live without it.

This is easy. Every neurological substance that induces addiction may induce (sometimes fatal) abstinence syndromes.

Heck, at a certain time, you can even forget about stealth. The target will be crawling up to you. If he asks for anyone else's help, he/she will stop getting the drug. He/She will not have that, especially if he/she is a dictator that won't have anyone deny him/her something.

Just make your evil chemists develop a carcinogen and highly addictive neurotransmitter, like nicotine.

7) Infection

This is, according to my opinion, the best strategy. Viruses may cause cancer because they are genetic invaders, that will cause DNA damage. Bacteria may cause cancer, because they may produce carcinogens internally.

Any microbiological laboratory would have the technology to genetically alter bacteria or viruses in order to turn them cancerigenous, if they would set their mind on it.

Helicobacter pylori is a bacterium that infects nearly half of the world’s population and it increases the risk of gastric cancer. We know there are strains that are more cancerigenous than others. Taint the food with a genetically altered H. pylori and you’re good to go.

Or why not alter a non-cancerigenous bacteria that is ubiquitous on our intestinal flora, like an E. coli?

Or create a hybrid flu virus. It would be airborne and extremely virulent. But give it genes that would incorporate on the host’s DNA in order to induce mutations. Or make it hijack the cellular machinery to produce and release carcinogens on circulation.

Pros: You would have to inoculate the target just once, thereby decreasing chances of detection. It could be airborne or foodborne (or, if you don't count that as physical contact, sexually transmited - just hire and inoculate a prostitute). Once inside the host, the microbe would self-perpetuate, without the need for more actions from the killer. You could just sit back and enjoy.

In the case of viruses, doctors wouldn’t be able to detect them, because they would be new viruses. They would only be found if the doctors knew a priori what viral antigens they should be looking for.

Cons Theoretically, a doctor could eventually detect the infection.

Pro pro But even if they did diagnose accurately those infections, that doesn’t mean they could treat them. Viral infections are extremely difficult to treat. And you could genetically engineer your bacteria with antibiotic-resistance plasmids.

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    $\begingroup$ Good answer. I would just like to caution that epigenetics as a true scientific discipline is in its infancy, and so most epigenetic theories you hear around are probably pseudoscientific. I don't think there is any evidence as of yet of how 'epigenetic tampering' could be accomplished, so it isn't really in the range of currently available technology, as the OP specifies. $\endgroup$
    – kingledion
    Commented Nov 30, 2016 at 21:52
  • $\begingroup$ @kingledion: Absolutely right. I did mention that on my comment. But I also said: "But it is not a stretch to believe that this technology will be available in a couple of years". Which, if current research proceeds on the current way, it could. $\endgroup$ Commented Nov 30, 2016 at 21:59

Use Stuxnet

Basically, you indirectly supply state-of-the-art medical facilities to your intended target. Let's say a CAT scanner or some other kind of diagnostic device.

When your target is observed going in for a check up, boot up your Stuxnet worm and overload the radiation dose (while logging the correct dose amount to cover up).

Repeat on a yearly/quarterly basis as required.

Bonus Answer (detection of assassination attempt)

Although people tend to trust computer logs implicitly, a suspicious security team may wish to use a radiation detector during use to ensure that the x-ray machine (or whatever) is really delivering the dose it says it is to the victim in question.

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    $\begingroup$ It just takes a bit of psychology. Print a few news stories of how unwell someone is ("Has El Presidente suffered a minor stroke?") and they'll react to disprove those rumours. It might take a few feet on the ground and some subtle tactics, but it could work out. $\endgroup$
    – user10945
    Commented Nov 30, 2016 at 14:36

In the news there was real-world case of man with HIV being infected with cancer from his parasite. His parasite had a cancer, but then its cancer cells invaded his body too because his immune system was too weak to stop them.


So the answer is simple. Induce cancer in a parasite by using radiation and then get your enemy infected by said parasite. But for this plan to work immunity of your enemy politician must be already weak (old age, bad genes, HIV-positive, etc).


Immortalization ex vivo

It sounds like a rather unlikely name for a method of assassination - so much the sneakier. The agent obtains live tissue from the victim by some means - anything from a swapped biopsy sample to perhaps hair follicles on a comb, if they're lucky. Then they do something like this, deleting genes that constrain cell growth, or adding new genes to direct it. Then the "immortalized" (which oddly enough, usually means cancerous) cells are injected back into the victim. The immune system might still do for them, but cancer cells tend to invent well established ways of reducing those risks, which you can have provided to them during your genetic manipulation.

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    $\begingroup$ It's rather depressing how easy it is for states to destroy an individual and not get caught. Great answer btw. I wonder if similar mRNA-based attacks are possible. $\endgroup$
    – user
    Commented May 17, 2022 at 6:20
  • $\begingroup$ @user CRISPR-Cas9 is a lot more involved than an mRNA vector, so "probably not". mRNA prints a protein, nothing else. But if you can successfully inject your target with something, there are definitely easier assassination routes. A drop of dimethyl mercury, say. $\endgroup$
    – jdunlop
    Commented May 17, 2022 at 18:30
  • $\begingroup$ @jdunlop - It should be possible - a classic animal model being Rous sarcoma virus. This could be one way to avoid biopsies and injections. But transmissible cancer viruses may be against the rules at Davos, and more importantly Pedro Gabriel already mentioned this category before I got here. $\endgroup$ Commented May 17, 2022 at 22:05

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