This week's artwork was donated by Vansom, a pediatric cancer patient who received treatment at The Children's Hospital of Philadelphia .
Tumor grade refers to the degree of abnormality of cancer cells compared with normal cells.
The body is made up of many types of cells. Normally, cells grow and divide to produce new cells in a controlled and orderly manner. This controlled cell division is the process that heals wounds and replaces aging tissues. Sometimes, however, new cells continue to be produced when they are not needed. As a result, a mass of extra tissue called a tumor may develop.