All cancers begin in cells. Our bodies are made up of more than a hundred million million (100,000,000,000,000) cells. Cancer starts with changes in one cell or a small group of cells. Usually, we ...

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com. Why is heart cancer so rare? – Jackson, age 12, ...