4 ms·

Yes, but other people are unaffected by that one person. That doesn't mean 100 percent chance of cure, but the chance remains the same for every person.

dekhn 13y ago
you're just pointing out a minor difference in my analogy. in cancer, the "population" is the tumor cells in a single human's body, while with bacteria, the "population" includes invading cells that infect multiple people and carry resistance between them. In both cases, the dividing cells propagate their inherited traits that allow them to evade the immune system or treatment. When you treat a person with a cancer drug, the cancer tumor population evolves (selection and natural variation), when you treat a population with an antibiotic, the bacterial population evolves. That was the point of my analogy.
- emiliobumachar 13y ago
  The analogy is valid, but the difference is not minor. With infectious disease, if there are ten possible mutations to make the pathogen resistant to treatment, each with a 1% chance of happening within the course of the disease in one patient, then pretty soon all mutations would be present in most of the whole pathogen population on Earth, because of natural selection. With non-infectious diseases such as cancer, in the same scenario, there would be about a 10% chance of the cancer cells developing one or more of the mutations in each patient, period. A tragedy for those 10% of patients, but a cure for the other 90%.
  - dekhn 13y ago
    you're missing the point. cancer is internally infectious. Primary tumors don't even really kill people that much- patients almost always die from metastases. These metastases typically are more resistant. Please read the entire book "Molecular Biology of Cancer". I'm just explaining small parts of it.
    - scribu 13y ago
      I guess the question then becomes: can the cancer cell population in a single patient evolve fast enough to evade the newly improved immune system, before it gets killed off completely?
      - dekhn 13y ago
        It seems unlikely. The genetic diversity was already created. Even when people report "we cannot detect any cancer cells in this person's body, so they're cured", they aren't saying there are no repositories in the body that harbor some resistant cells, whcih will then go walk up the exponential growth curves every aggressive tumor always does.

dekhn 13y ago

you're just pointing out a minor difference in my analogy. in cancer, the "population" is the tumor cells in a single human's body, while with bacteria, the "population" includes invading cells that infect multiple people and carry resistance between them. In both cases, the dividing cells propagate their inherited traits that allow them to evade the immune system or treatment. When you treat a person with a cancer drug, the cancer tumor population evolves (selection and natural variation), when you treat a population with an antibiotic, the bacterial population evolves. That was the point of my analogy.

emiliobumachar 13y ago
The analogy is valid, but the difference is not minor. With infectious disease, if there are ten possible mutations to make the pathogen resistant to treatment, each with a 1% chance of happening within the course of the disease in one patient, then pretty soon all mutations would be present in most of the whole pathogen population on Earth, because of natural selection. With non-infectious diseases such as cancer, in the same scenario, there would be about a 10% chance of the cancer cells developing one or more of the mutations in each patient, period. A tragedy for those 10% of patients, but a cure for the other 90%.
- dekhn 13y ago
  you're missing the point. cancer is internally infectious. Primary tumors don't even really kill people that much- patients almost always die from metastases. These metastases typically are more resistant. Please read the entire book "Molecular Biology of Cancer". I'm just explaining small parts of it.
  - scribu 13y ago
    I guess the question then becomes: can the cancer cell population in a single patient evolve fast enough to evade the newly improved immune system, before it gets killed off completely?
    - dekhn 13y ago
      It seems unlikely. The genetic diversity was already created. Even when people report "we cannot detect any cancer cells in this person's body, so they're cured", they aren't saying there are no repositories in the body that harbor some resistant cells, whcih will then go walk up the exponential growth curves every aggressive tumor always does.