Cancer 101 | National Geographic

What is cancer, and how does it start? Find out how genetics play a role, which types of cancer are the most prevalent, and what is being done to fight this deadly disease. ➡ Subscribe: About National Geographic: National Geographic is the world’s premium destination for science, exploration, and adventure. Through their world-class scientists, photographers, journalists, and filmmakers, Nat Geo gets you closer to the stories that matter and past the edge of what’s possible.