Hello everyone!  I recently took a class in macroevolution (evolution on a long time scale, "the big picture") and learned the basics behind why cancer develops.  This is a generalization of the story behind the evolution of cancer. (Don't worry I am not going to throw a bunch of super complicated words at you!). Disclaimer: if you do not believe in the evolution of cells, please do not be offended by my story below.

In the beginning….there were single celled organisms called prokaryotes (ex. bacteria).  Billions of years later slightly more complex organisms called "eukaryote-like" organisms started appearing and it is the friction between these two that has led to what we know as cancer today.

Once these eukaryote-like organisms started roaming the world, they sought to "exploit" these prokayotes by "eating" them, but not digesting them. This way inside their cell, they could use the prokaryote's machinery for its own purposes. One example is the modern day chloroplast in plant cells which allows them to carry out photosynthesis.  This progressed into a "symbiotic" relationship (means both sides get something out of it) because the prokaryotes got protection and the eukaryote-like things get to exploit their machinery.  This cooperative effort led them to co-evolve together and make the modern day eukaryotes (humans and dogs fit into this general group!).

As with any relationship between two beings, parent-child, husband-wife…there is friction. There is a sort of "competition" for maximizing what is best for each one, but without rules, it would be detrimental to the other. So in order for the prokaryote and the eukaryote to get along, these "rules" got encoded into the DNA as a way to regulate one another. When these rules are broken because someone is being selfish and wants to "maxamize" itself, BAD THINGS HAPPEN!

How Cancer fits into this story: These "rules" have been around for billions of years and are the same "rules" that regulate all the different cells in our body. Pretend the cells in your body are the prokaryotes and your body is the eukaryote. The cells are supposed to be working for you and in return, you provide them with a well-fed, perfectly temperature regulated environment. This is how the symbiotic relationship should be.

        When the "Rules" are broken cancer develops. How you ask? Lets pretend that some of the cells figure out how to "break" the rules because they are tired of being told how much they can grow, how fast they can grow etc… So once these little mutinous cells break the rules, they start going crazy and grow differently than the rest of their obliging compatriots. There are some "enforcers" like our immune system, but they are no match for these cells with newfound freedom and once the "enforcers" are overwhelmed, the cancer starts affecting the body.  These selfish cells want to party on their own terms, but really they will die once the body does. It is essentially counter productive, but they don't care because they are having the times of their lives…

So basically cancer is part of who we are because it is inextricably tied to where we came from.

I hope this can give you a better understanding of why there is cancer in the world and I hope I wrote it in an entertaining manner

-Chloe's mom (aka. Major Bio Nerd)

The technical term for a cell "eating" another cell is called phagocytosis. I think this image explains it perfectly:

kbryant said:

 But my question is why haven't we been able to come up with a way to manage this disease like we do with say heart disease or diabetes…. we've talked about this on the forum before – it's an interesting concept to look at it this way vs. finding the cure (which would be great if that were possible.) Cancer seems to fall so far behind in the advances that have been made with these other chronic diseases….just doesn't make sense if that makes sense. It's truly perplexing….

Well, from my limited knowledge on the subject (being a bio major), I seem to recall in my genetics course that the way cancer develops (or any genetic trait for that matter) depends on a variety of factors (these are the biggies).

   1. Environmental influences: certain external sources (environment) can "trigger" the cancer.  Such as carcinogenic substances found in cigarettes, which when exposed to it (depending on exposure level amount and number of times) can make you more likely to develop cancer.

   2. Genetic predisposition: some DNA sequences that lead to cancer are slightly different from one another and affect how and when the cancer can be triggered.  

   3. Individual health: as with any ailment, the condition of your body definetly affects whether or not you will get sick. Like being physically fit vs obese, eating healthy vs eating junk food…

   4. Level of expressitivity: Basically means how "bad" or "less bad" the cancer will affect the body based on criteria of #1-3. That is why some people can go through chemo, go into remission and live out the rest of their life cancer free. They most likely had a "light" version of the cancer.

Because there are so many criteria that go into how a person is affected by the cancer, it is hard to find a "cure". I know that there are some controversial studies about "Gene therapy" (won't get into too much detail), but basically trying to rid the affected cells of the "bad genes" and replace them with a benign sequence.  The most controversial part of this is "correcting" of ailments is in fetusus in vitro since the individual would have no consent and the procedure is not guaranteed to work (no known studies have been done with this, it was just discussed as a theoretical possibility for preventing certain congenital issues that could be diagnosed pre-birth).

There are some new "nuclear" science methods that basically use a fluorescent tagged molecule that is bound to a specific nutrient that a particular type of cancer likes. This nutrient is used to a far greater extent than the surrounding body cells, so when special "Cat Scan" type of test is run on the body, the affected areas are "lit up". The cancer is metabolizing that nutrient much greater than the other cells, so there is a higher concentration of fluorescent dye in it.  The only down side is that it takes SO long to figure out the right type of fluorescent molecule and the right type of nutrient so that the individual having the tests run on them doesn't get sick from ingesting the radioactive stuff.  There is an accompanying procedure (I don't remember exactly from my physics class), that has been used for certain types of cancers and targets ONLY those "lit" up areas.   With the computer programming now a days there are 3D images that pop up on the screen, so no invasive surgery is needed, the cancer cells are the only ones affected and the patient has minimal side effects (because it isnt killing everything). Probably best to look up more Nuclear Medicine facts on your own, since this is my limited knowledge on the sugject. This is probably the most "cutting edge" stuff that is out there for curing cancers. 

Ok I think I have written enough and I hope I didn't lose anybody along the way!

-Chloe's mom