Story highlights BethAnn Telford, 47, will run seven marathons in seven days on seven continentsTelford was diagnosed with brain cancer in 2005Her goal is to raise $1 million to support brain cancer research(CNN) For the past three years, BethAnn Telford has trained for a grueling athletic achievement, the World Marathon Challenge. It's seven marathons on seven continents over seven days. "I am the only USA woman and the only person with live cancer cells in my body [competing]," she said. Long before Telford's cancer diagnosis, she was an avid marathoner. In October 2004, as she headed toward the Marine Corps Marathon finish line, she heard a loud pop in her head.

Source: CNN January 19, 2017 22:31 UTC