Bio q-pack question #5

[theonlytycrane]

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The question stem states that bacterial infection may cause stomach cells to multiply. Wouldn't this possibly cause cancer in itself?

I wasn't sure why the answer was stating that a mutation would need to occur in addition to bacterial infection for cancer to occur.

 

[aldol16]

Well, proliferating cells do not cause cancer per se. Cell proliferation is just one aspect of cancer. Cancer cells must also perform other tasks, e.g. shut down apoptosis, upregulate angiogenesis, etc. So you need either the turning on of an oncogene or turning off of a tumor suppressor for these cells to become cancerous. Otherwise, they've just increased in number, maybe causing a thickening of the stomach lining.

 

[wizzed101]

It sorta does. Cancer happens when there are errors in the genome. Errors can be caused by many things but generally, the more cells multiply, the more susceptible they are. There are tons of things that can go wrong during mitosis and likewise, tons of mechanisms to repair the damage. But they are not 100% effectively. It's just a number game. You have, say 0.001% chance to get cancer per mitosis. Would you want your cells to regenerate every 20 days or every 2 days?

 

[aldol16]

It sorta does. Cancer happens when there are errors in the genome. Errors can be caused by many things but generally, the more cells multiply, the more susceptible they are. There are tons of things that can go wrong during mitosis and likewise, tons of mechanisms to repair the damage. But they are not 100% effectively. It's just a number game. You have, say 0.001% chance to get cancer per mitosis. Would you want your cells to regenerate every 20 days or every 2 days?

To visualize the above point, OP, you imagine the logic of the question going like this (it's flipped relative to how we normally think of cancer). Instead of genetic mutations -------> proliferation ---------> cancer, it goes proliferation --------> genetic mutations --------> cancer. For the first case, if you have proliferation, then you have cancer. In the second case, there's an intervening step between proliferation and cancer.