By Samuel Meade Gareth Southgate and Gary Lineker are among those in the world of sport to have sent wishes of support to Kate Middleton after the Princess of Wales confirmed a cancer diagnosis. The Royal spoke out in a video on Friday to announce she has begun preventative chemotherapy treatment. Buckingham Palace says they will not be sharing any further private medical information, including the type of cancer. The Princess said it was a “huge shock” after an “incredibly tough couple of months”. The video statement from Kate explained that when she had abdominal surgery in January, it was n…