schwit1 quotes a report from ScienceAlert: Two scientists have come up with a depressing new hypothesis that attempts to explain why cancer is so hard to stop. Maybe, they suggest, cancer's not working against us. Maybe the disease is actually an evolutionary 'final checkpoint' that stops faulty DNA from being passed down to the next generation. To be clear, this is just a hypothesis. It hasn't been tested experimentally, and, more importantly, no one is suggesting that anyone should die of cancer. In fact, it's quite the opposite -- the researchers say that this line of thinking could help us to better understand the disease, and come up with more effective treatment strategies, like immunotherapy, even if a cure might not be possible. So let's step back a second here, because why are our bodies trying to kill us? The idea behind the paper is based on the fact that, in the healthy body, there are a whole range of inbuilt safeguards, or 'checkpoints,' that stop DNA mutations from being passed onto new cells. One of the most important of these checkpoints is apoptosis, or programmed cell death. Whenever DNA is damaged and can't be fixed, cells are marked for apoptosis, and are quickly digested by the immune system -- effectively 'swallowing' the problem. No mess, no fuss. But the new hypothesis suggests that when apoptosis -- and the other safeguards -- don't work like they're supposed to, cancer just might be the final 'checkpoint' that steps in and gets rid of the rogue cells before their DNA can be passed on... by, uh, killing us, and removing our genetic material from the gene pool.