If scientists/doctors were to attribute the single biggest hurdle or blockade to there being a cure for say, HIV/AIDS, what would it be? I’m sure there’s at least one huge thing keeping them back, after all I’m sure they know what causes it and theoretically how to fix it, but it’s just not achievable at this time.
What about cancer? Or could there even be a singular “cure for cancer” considering all the different varieties of cancer?
I don’t know anything specifc but I found this article really helpful in learning about the development of cancer-related drugs.
I suspect that a medical researcher could list a dozen different approaches which might plausibly work for each of those diseases. None of them work just yet, but they probably each have a different stumbling block. So I doubt there’s going to be any single answer to your question.
The short answer: Mutation.
Mutation in the HIV/AIDS virus and cancerous cells within a patient allow these diseases to evade medications. Modern treatments try to attack with cocktails of medications that kill pathogenic cells in different ways, in an attempt to wipe out the buggers before they have a chance to mutate. But, they are tricky. They can decided to go into hiding for a while. Or they’ll start making protiens to protect themselves from the medication. Often, these protiens will make them immune to other similar drugs.
Add to that the fact that these medications are just this side of poison to healthy cells, and what you have is a big damned problem.
The second biggest problem is that you have to get every last HIV virus particle, and every last cancer cell, in order to really be free of the disease. So long as one remains, there is always the chance of the disease coming back.
Cheerful stuff.
Do cancer cells actually have higher rates of mutation than noncancerous cells of a similar type? My understanding was that cancer was caused by somatic mutations that affect the regulatory pathways that control cell growth, and since there are innumerable ways this could happen, different types of cancer could have different causes.
First off: I’m no cancer expert. But, I’ve had a lot of professors talk about neoplasms in the course of my studies. I don’t have a site for any of this because I’m pulling it from multiple places. But, I imagine any good human biology text book will be more thorough and accurate than me.
What I’m going to say applies to both benign and cancerous neoplasms. (What seperates the two is just how screwed up the cells get.) Since more people are familiar with the term cancer than neoplasm, I’ll use it.
What you say is true, cancers happen because of a mutation that causes unregulated cell growth. Because cell growth is regulated lots of ways, there are lots of different mutations that could lead to cancer.
However, regardless of what initially caused the mutation, once they are damaged, cancer cells have a higher rate of mutation over normal cells. It works like this:
Cancer happens when there is damage to either:
DNA replication is complicated, and often mistakes happen in the copying. Normal cells will stop and try to fix their new DNA when they get it wrong, killing themselves if the problem is too bad. They do this this, as they do everything, through a complex series of protein interactions. Many cancer cells won’t stop or suicide because the genes that code for repair or suicide proteins are damaged and the protein is broken. Without a way to either correct DNA or stop themselves, cancer cells will continue to divide and the natural mistakes that would have been corrected build up.
Cancers can be caused by other DNA damage that is initially unrelated to DNA repair, like having a virus stick an unregulated promotor sequence right before a growth promoting sequence, or not making receptors for growth inhibitory signals, or losing the receptors necessary to attach correctly to neighbor cells. For whatever reason, the cell starts dividing rapidly. All this replication frenzy increases the likelihood of incorrect DNA copying because the cell is just going like mad and can’t get together the several proteins it needs to repair the DNA before it’s off to the next stage in cell division. So, even if the initial damage isn’t related to DNA repair, the DNA gets more and more mutated.
Here’s where the problem with cancer therapy comes in:
By the time cancers are of a detectable size, there are already millions of cancer cells present. The cancer will be made of mini-populations of cells that all have slightly different numbers and kinds of mutations.
Anti-cancer drugs and radiation therapy are designed to attack cells that are rapidly dividing. Really, that’s the only universal feature that makes the cancer cells different from your healthy cells. The drugs or radiation get in there and either halt growth pathways or cause more DNA damage. As damaged as the DNA already is, there is some minimal amount of functionality the cancer cell needs to live. Your healthy cells still have working repair systems, so they recover. The cancer can’t. However, especially for drugs that only work by inhibiting growth pathways, cancer cells with subtly different mutations may not need the particular growth pathway that the drug attacks. Pretty soon, all the sensitive cells in the cancer are dead, leaving the resistant ones to flurish. Using drugs that attack by different pathways is therefore preferable. But, these drugs will also hurt the healthy cells in your body that naturally replicate a lot, like the cells lining your digestive tract. That’s one reason why chemo drugs are so toxic.
Other chemo drugs and radiation work by heavily damaging the DNA in replicating cells instead of attacking growth pathways. But, you can see how this is problematic. Yeah, you might kill all the cancer, but you could also induce new cancer in healthy cells. And you still have the problem with cells that naturally divide a lot.
The drug Gleevec mentioned in the linked article above works by attacking cells that are expressing a particular mutated protein. Certain kinds of cancers will have a common mutated protein on their surface. Just happenstance. That lets the drug tell the cancer apart from healthy cells. It’s especially handy in slow growing cancers where normal chemo drugs don’t have the opportunity to attack. But, this only works so long as the cancer cells keep expressing that mutated protein. And, the drug won’t work against other cancer types.
If mutation isn’t the number one reason why there isn’t a cure for cancer, I don’t know what is.
It is the same reason we can’t solve societal problems. Complexity. Our solutions only apply to a limited number of situations. Our understanding of the interactions of the thousands of chemicals in the body is limited. We make small discoveries here and there but we are nowhere near the point where we can map out all the interactions. Sometimes the concentration of chemical involved in a physiological change may be so small as to be barely detectable. Sometimes small changes cascade into a larger overall effect.
Don’t forget that there are hundreds of different types of cancer as well.
By the way, most cancers are preventable. Strive to live a healthy life by eating properly, exercising, reducing stress and you will have a reduced risk for cancer.
Well, many cancers may be preventable, but many are not. Genetics often plays a role as do certain environmental factors that are not related to behavior. So get screened for any cancers you see in family members or in other people your age so that you can catch anything early.
And I think this is because the HIV virus attacks the immune system itself and the cancer cells are a production of our own body so the immune system doesn’t attack them as foreign.
Sorry if this is a hijack, but putting ethics and moral obligations in the medical and scientific community aside, do companies have more motivation in finding a cure or in continuing to make medication to treat HIV/AIDS?
I think a lot of it depends on where you’re talking about, geographically. One article from the world AIDS meeting (last year, I think) said that getting or being a married woman in parts of Africa raises your chances of contracting AIDs simply because women’s rights don’t allow them to refuse sex with their husbands who have been floozing around with infected women. In that regard, one of the biggest hurdles to controlling it’s spread hinges on women’s rights.
In the U.S…it used to be that education seemed to be the key, but I’m not sure that’s the biggest hurdle anymore. According to this article, Injection Drug Use: Background, Pathophysiology, Epidemiology it appears IV drug use accounts for 61% of the HIV/AIDS cases among women in the U.S.
All in all, it looks like peripheral problems need to be fixed before we can get a handle on it.
The OP was asking about curing, not preventing. If we could cure AIDS, the vector of infection would be irrelevant; let people get it: we’ll just cure 'em.
And, pessimistically, I’m sure we’ll have cures to both AIDS and cancer (perhaps nanobots or some similar “universal” cure) long before we have worldwide gender equality and religious freedom–even if we’re centuries away from the cures.
No. If you think it through, you might be able to string people along for awhile, and rake in the dough, but what happens when your competitor does find a cure? All the sudden you have no business and the other guy is rolling in the dough. Unless you think there is some kind of conspiracy between all pharmaceutical companies and they are, or will, suppress the most sought after life-saving cures…