Comment by hinkley
1 day ago
Tumors excreting chemicals to prevent destruction doesn’t sound like DNA damage, that sounds like evolution.
We know some cancers can be caused by viruses. And we know a few cancers that act like viruses in dogs and Tasmanian devils, and some rare cases in humans.
We only figured out that ulcers are bacterial in origin within the lifetimes of many HN readers, and there are signs that other GI issues may be bacterial or viral (or bacteria-targeting viral) as well.
Maybe we need to start culturing and DNA testing cancers.
We already culture and DNA test cancers. Sometimes we can point at a secondary tumor and say "it came from this primary tumor". And we already know viral and bacterial infections can increase the likelihood of people getting malignant tumorws.
Most scientists wouldn't call the hallmarks of cancer "evolution". I think instead most would say that cancer is an almost certainly unavoidable outcome of the complexity of eukaryotic organism's control of cellular replication.
There's a series of papers organized around the "Hallmarks of Cancer" which help explain why nearly all tumors show the same properties- and how they are effectively due to dysregulation of evolutionary checkpoints and signalling. generally, an organism with a malignant tumor is less likely to reproduce. However, it's really far more complex than that ,
Do we understand the early dynamics of cancer? Do the hallmarks need to appear more or less at the same time by chance, or can the cancer cells acquire them sequentially, which would then induce a local microevolution process?
>>> generally, an organism with a malignant tumor is less likely to reproduce.
Huh?
What is meant by this? Like if you have cancer, you are less likely to want to reproduce? Or, less likely to reproduce due to the illness?
You're right, DNA damage is just one of the types of genetic variation in cancer. There are many other structural variations that act like remixes.
"Maybe we need to start culturing and DNA testing cancers." I assure you this is being done at a massive scale.
Due to cellular stress, cancer cells disobey multi-cellular governance. They behave more like independent organisms fighting for survival, reverting to primal programming.
Oh I know we are trying to genomically test them for oncology research and potential treatment plans, but do they do paternity tests on them?
I was trying to remember which mammal in Australia gets tumors from fighting, and I found a reference to a mother getting melanoma from her daughter. It’s unclear to me whether the cancer transmission was rare or the identification is rare.
There’s very often a comparison to the somatic (i.e. non-cancer) genome of the same patient. It’s a great way to quality control that there wasn’t some sample mixup in the lab.
Transmission of cancer is rare in humans—if it were not, it would make someone’s career to find many cases of it. While we can’t say that all sheep are white, we’ve looked at enough of them to say that black sheep are not common. Furthermore, it’s very clear how the Tasmanian devil cancer is spread—it’s around the mouth while they are biting each others faces; it’s not as obvious how one would spread most human cancers.
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tasmanian devils [edit: I guess you already said that] https://en.wikipedia.org/wiki/Devil_facial_tumour_disease
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Tasmanian devils.
The cancer problem always struck me as more of a control theory challenge than a purely biological one.
A cancer is necessarily a line of cells that survived despite the mechanisms that should prevent it from surviving. It's evolution in a way - genotype a sequence of random mutations and environmental factors away from the original that allows the cell line to sidestep the immune system. Coincidentally the immune system based off of the same original genotype. The ones that don't survive are not causing cancer.
To provide more color on cancers caused by viruses, the World Health Organization (WHO) estimates that 9.9% of all cancers are attributable to viruses [1].
Cancers with established viral etiology or strong association with viruses include:
- Cervical cancer - Burkitt lymphoma - Hodgkin lymphoma - Gastric carcinoma - Kaposi’s sarcoma - Nasopharyngeal carcinoma (NPC) - NK/T-cell lymphomas - Head and neck squamous cell carcinoma (HNSCC) - Hepatocellular carcinoma (HCC)
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC8831861
>Tumors excreting chemicals to prevent destruction doesn’t sound like DNA damage, that sounds like evolution.
One cell's DNA damage is another cell's evolution.
> ulcers are bacter
To be clear, some peptic ulcers are caused by H. pylori, but not all ulcers.
The guy who won the Nobel prize for giving himself an ulcer estimated it as 90%, which is very comfortably “most”. If that has been drastically estimated down I hadn’t heard.
Also don’t abuse advil, kids. OTC painkillers can burn a hole in your digestive tract. I in fact know someone missing a few feet of intestine because of chronic back pain and overuse of non narcotic painkillers.
> The guy who won the Nobel prize for giving himself an ulcer estimated it as 90%
That's worldwide. In developed countries the proportion is closer to 10 to 15% [1, 2]
[1] https://www.jwatch.org/na50875/2020/02/24/prevalence-h-pylor...
[2] https://pubmed.ncbi.nlm.nih.gov/31972622/
I did the oops too much Advil on myself naively over years. Gastritis and resolves once the cause is figured out but scared me to respect otc meds more.
Yeah the real outcome of all this was "stress is not a cause of ulcers and other GI issues, but it can increase the negative impact" and "some uclers and other GI issues can be treated by antibiotics".
Stress of course makes pretty much all multicellular organisms more susceptible to pathogens and environmental toxins. But it’s the trigger not the bullet.
They do genetically sequence cancers today, at least looking for specific markers.
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https://de.wikipedia.org/wiki/Alfons_Weber_(Mediziner,_1915)