What is cancer?

Alright, imagine your body is like a big city with lots of little buildings called cells. These cells are like tiny workers that do special jobs to keep the city running smoothly. Sometimes, a few of these workers get confused and start doing their jobs all wrong. Instead of stopping when they're supposed to, they keep working and building more and more buildings on top of each other, making a big messy pile.

This messy pile is what we call cancer. It's like when you build too many blocks in one place, and it gets really wobbly and messy. Doctors are like city helpers who try to clean up the mess and help the city work properly again.