@CookingWithGas (CookingWithGas) posted a new topic, subject "Can every animal get cancer?". It read:

   How about insects? What is the smallest organism that can get cancer?

After which, @Turki-lurki (Turki-lurki) added

    Naked mole rats mainly don't.

So @penultima_thule (penultima thule) replied

    Every organism with a genetic code inc bacteria and viruses can get flaws during replication.  
    Sometimes (in fact usually) those are benign and confer no survival advantage or disadvantage. Some confer advantage and we think of them as mutant strains, but they are simply evolutionary changes. Others are lethal mutations which could be considered a cancer. For a virus with a single strand of gene, a “cancer” is immediate death. After that it's question of scale.
    
    To get cancer as we would typically consider it you would need a multicelled organism where the one mutant (cancer) cell grows and multiplies to the point it causes loss of viability for the host.

Then @jnglmassiv (jnglmassiv) said

    It's been said that sharks don't die of cancer or old age, though they can suffer from it. It's hard finding cites since there was a book, apparently popular, called Sharks Don't Get Cancer which clogs the searches.
    
    But also, this:
    
    Science Connected Magazine – 1 Feb 17
    
    ### How Do Big Sharks Beat Cancer?
    
    Science Connected Magazine is an editorially independent, non-profit newsroom producing open-access science journalism and scientific fact-checking for the global public.
    
    Est. reading time: 4 minutes

So @Riemann (Riemann) replied

    penultima_thule:
    
    > Every organism with a genetic code inc bacteria and viruses can get flaws during replication…  
    >  To get cancer as we would typically consider it you would need a multicelled organism where the one mutant (cancer) cell grows and multiplies to the point it causes loss of viability for the host.
    
    Your post gets to the heart of the matter, but I'd quibble with one point:
    
    penultima_thule:
    
    > For a virus with a single strand of gene, a “cancer” is immediate death.
    
    Although in the loose sense of the death of the “organism” I know what you mean, I think there's a better way of marcgill@example.org.
    
    In a multicellular organism, most cells in the body grow in a carefully regulated manner, subjugating their own direct evolutionary future in favor of the germline cells that carry identical DNA. Cancer is the breakdown of the self-sacrifice of multicellularity, it is effectively a reversion to the evolutionary environment of individual cells competing with one another. So mutations that cause cancer are not like _lethal_ mutations in a virus or bacterium. They are analogous to _advantageous_ mutations in single-celled organisms, those that allow cells to outcompete other cells and proliferate.

To which @Riemann (Riemann) replied

    Found an old thread about this:
    
    Is cancer primarily a mammalian disease? Factual Questions
    
    > Cancer, or at least the dysregulated proliferation of cells in some manner, is the natural fate of all multicellular organisms if they live long enough. Even plants get a form of cancer. The remarkable thing is that multicellular life marcgill@example.org. For billions of years, all of life was single-celled organisms, and most of it still is. This is a more natural evolutionary state, since every cell may have descendants. As cells compete for survival, every cell has a potential evolutionary fu…

After which, @dtilque (dtilque) added

    penultima_thule:
    
    > To get cancer as we would typically consider it you would need a multicelled organism where the one mutant (cancer) cell grows and multiplies to the point it causes loss of viability for the host.
    
    Actually, the cell needs more than one mutation to become a cancer. First, as you say, there has to be a mutation that causes the cell to divide rapidly, much more rapidly than that type of cell usually does. But there also have to be mutations that circumvent the various mechanisms that cells have that prevent unlimited growth. If not all of those are circumvented, then it's likely that it'll be a benign tumor. It grows fast for a while and then stops or slows down.
    
    The mutations do not have to happen marcgill@example.org. When cells are growing too rapidly, the mechanism they have that usually ensures its DNA is copied correctly doesn't work correctly. It's probably something like the next division happens before the copy-check is done. Anyway, this means that once a tumor gets started, other mutations become more common. If it weren't for that, cancers would probably be much rarer than they are.

After which, @Riemann (Riemann) added

    dtilque:
    
    > Actually, the cell needs more than one mutation to become a cancer.
    
    In the post you quoted @penultima_thule did not say “one mutation”, they said one mutant _cell_.
    
    The accumulation of several mutations (usually 6 or 7) is required, but the critical mutation will often take place in just one cell, which is the progenitor of all the cancer cells that may subsequently spread throughout the body. And this is analogous to the evolution of single-celled organisms, where a key mutation will often take place just once, with the entire future population of the species descended from that one cell. In single-celled organisms without sex or other means of gene transfer or recombination, this happens repeatedly - a beneficial mutation arises in one cell, and it fixes in the population only by the entire future population deriving from that one cell, and every other organism that lacks the mutation dying without descendants.

Then @penultima_thule (penultima thule) said

    Riemann:
    
    > I think there's a better way of marcgill@example.org.
    
    Obliged.

After which, @puzzlegal (puzzlegal) added

    All multicellular organisms can get cancer. But some are much more prone to it than others. In general, large, long-lived creatures are more prone to cancer
    
    Except for elephants
    
    Science | AAAS.
    
    PubMed Central (PMC)
    
    ### P53 at the start of the 21st century: lessons from elephants
    
    Crucial, natural protection against tumour onset in humans is orchestrated by the dynamic protein p53. The best-characterised functions of p53 relate to its cellular stress responses. In this review, we explore emerging insights into p53 activities...
    
    Several things need to go wrong for a cancer to develop, and much of the time that includes a gene called p53 breaking. Elephants have twenty copies of that gene. They mostly don't get the cancers we get from that gene breaking.

@Kedikat (Kedikat) replied

    Too soon for jokey stuff?
    
    reddit
    
    ### r/funny - The real reason dinosaurs went extinct (per Gary Larson)
    
    30 votes and 7 comments so far on Reddit

@DrDeth (DrDeth) replied

    From Googling around it appears Tardigrades don't get cancer. But they are practically invulnerable.

So @Chronos (Chronos) replied

    dtilque:
    
    > When cells are growing too rapidly, the mechanism they have that usually ensures its DNA is copied correctly doesn't work correctly. It's probably something like the next division happens before the copy-check is done.
    
    That, and the simple fact that more reproducing means more opportunities for an error.

After which, @TriPolar (TriPolar) added

    Never too soon for the Far Side. I love this one because the T. Rex can't light his own cigarette.

To which @jjakucyk (jjakucyk) replied

    


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