It's not clear what causes Wilms' tumor.

Doctors know that cancer begins when cells develop errors in their DNA. The errors allow the cells to grow and divide uncontrollably and to go on living when other cells would die. The accumulating cells form a tumor. In Wilms' tumor, this process occurs in the kidney cells.

In a small number of cases, the errors in DNA that lead to Wilms' tumor are passed from parents to children. In most cases, there is no known connection between parents and children that may lead to cancer.

Nov. 06, 2014