Graft-versus-tumor effect

Okay kiddo, so imagine that your body is like a castle with lots of warriors to protect it. Sometimes bad guys, like germs or viruses, try to attack your castle and make you sick. But your warriors are there to fight them off and keep you safe.

Now, imagine that someone gets really sick with cancer. The cancer cells start to grow and multiply out of control, which is very bad. They are like an army of bad guys attacking your castle.

One way to fight cancer is to use medicine called chemotherapy or radiation therapy. These treatments can kill the bad cancer cells, but they can also hurt the good cells in your body.

Another way to fight cancer is to get a new set of warriors to help fight the bad cancer cells. These warriors are called stem cells, and they can be taken from someone else and put into the sick person's body. This is called a "graft" or a "transplant."

But here's the cool part. When the new warriors – the stem cells – enter the sick person's body, they not only fight the bad cancer cells, but they also remember what the bad cancer cells look like. So even after the cancer cells have been killed off, the new warriors keep patrolling the sick person's body to make sure they don't come back.

This is called the "graft-versus-tumor effect." The new warriors – the stem cells – are attacking the bad cancer cells, and this is helping to keep the sick person safe. It's like having a whole new army to fight off the bad guys, and they won't stop until every last bad guy is gone.