33. Karen Joy Miller

After being diagnosed with breast cancer at 42, Miller wanted to know how and why she got cancer and how she could have prevented getting the disease. Since then, she has become an expert on the subject, helping to inform others on how to prevent breast cancer and other environmental diseases. In 1992, she founded the Huntington Breast Cancer Action Coalition, a not-for-profit grassroots organization designed to educate people on awareness and prevention, and help those coping with the disease. She also founded Prevention is the Cure, which believes that disease is not caused by genes alone but by the interaction of environment triggers and genetics.