Here's a breakdown:

* Cancer cells grow and divide uncontrollably: This is the fundamental characteristic of cancer. They don't follow the normal rules of cell growth and division.

* They invade surrounding tissues: Cancer cells can break free from the original tumor and spread into nearby tissues.

* They travel through the body: Cancer cells can enter the bloodstream or lymphatic system, which allows them to travel to distant parts of the body.

* They form new tumors (metastases): Cancer cells can establish new colonies in other organs, leading to secondary tumors.

So, the process of cancer cells spreading and replacing healthy tissue is known as metastasis.