What started out like a typical stomach virus for 7-year-old Eva quickly revealed itself to be something much more serious: a Wilms tumor. While Wilms tumor is the most common kidney tumor in kids and has a high cure rate, Eva's stage IV anaplastic Wilms tumor was very rare and challenging. After months of aggressive treatment at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, Eva has recovered and is focusing her attention on her favorite sport: horseback riding: http://ms.spr.