Perthshire cancer survivor who lost her sister to the disease has launched this year’s Swimathon fundraising event in Scotland.Breast cancer claimed the life of Donna McGuire’s sister Gwen Angus in 2011 aged just 50.Donna, who carries the faulty BRCA2 gene – known to increase the risk of breast and ovarian cancer – is determined to do everything she can to support life-saving research and uncover the genetic link to cancer which has cast a shadow over her family’s life.And she has inspired her