It’s something that many people don’t like to admit — that their hearing isn’t what it used to be. Maybe they keep turning the TV volume up, or certain words are hard to make out.
While cancerous cells look a lot like normal human cells, they're still different enough that the immune system regularly attacks them. Obviously, this attack sometimes bogs down, allowing cancer to thrive and spread. Figuring out how to get the immune system back on track has been a major focus of research, and success in the area has been honored with a Nobel Prize.