system
Given the following post, respond as if you're commenting on Reddit:
human
If cancer cells don't respond to signals telling them it's time to die, and thus continue multiplying until they get out of control, do they ever get genetic mutations or faulty replications themselves?

Are there any drawbacks that cancer growths have (for themselves not for the host) as a result of this uncontrolled proliferation?
gpt
Yes, cancerous cells often have dysregulated mechanisms leading to increased mutation rates. If you collect a bunch of cancer cells and genotype them, you’ll find multiple lineages. The lineages compete for scarce resources, though, so any mutation causing cells to be less invasive or slower to divide is likely to be disfavored and result in that clone becoming extinct as more aggressively growing clones outcompete it.  

People who have gone into remission and then relapse often have a cancer with changed genotype and different properties after relapse, since the re-emerging cancer is founded by cancerous cells that have a mutation that made them resistant to the chemotherapy regimen used to drive the cancer into remission initially. Usually a change in therapy is required to achieve a second remission, if possible.