What is Intra-tumor evolution?

Intra-tumor evolution is when cancer cells inside a tumor change and become different over time.

Imagine you have a big pile of toy blocks, all red at first. But as you play, some of the blocks start to change color: one becomes blue, another turns green, and so on. These changes happen because each block is like a cancer cell, and they can grow and change in different ways.

Think of a tumor like a garden. At first, all the plants are the same, maybe all roses. But as time goes by, some roses start to grow taller, others get more colorful, and a few even turn into daisies! This is because each plant (or cancer cell) can have its own way of growing and changing.

This change inside the tumor makes it harder for doctors to treat. Just like how you might need different tools to take care of different types of plants, doctors may need different treatments for the different kinds of cancer cells inside a tumor.