A survey of 501 school children ages 9-16 in Britain indicates they don't know what causes cancer. The poll, conducted for the Macmillan Cancer Support, a British non-profit group that supports those with cancer and their families, indicated 97 percent of the students said they didn't know sunburn could cause cancer and 9 percent didn't know smoking causes cancer. However, 2 percent said they thought cancer was a result of being badly behaved, while 4 percent said they thought it can be caught from someone else. Twenty-one percent said they thought cancer was always fatal, 52 percent said they didn't know what cancer was -- even though 67 said they knew someone diagnosed with cancer, the survey said. Katherine Donnelly of Macmillan Cancer Support said the findings indicated why 53 percent said they were frightened when they heard the word "cancer." "The unknown is always scary and, as our survey has shown, cancer is something school children don't know a lot about. As cancer affects more and more people -- 1-in-3 adults -- the chances of children knowing someone with the condition grows. This can be really distressing and they may feel too worried to ask questions," Donnelly said in a statement. "Just over one-quarter of children have been taught about cancer at school and this needs to improve." The Macmillan/TNS survey of children ages 9-16 was conducted Aug. 3-9 August. No margin of error was provided.