Background
Although treatment of childhood leukemia has greatly improved, many cases are severe and current therapies are inadequate. Leukemia is caused by a collection of mistakes in DNA, the blueprint within every cell. A family of proteins called APOBEC3 has recently been proposed as a cause of mutations in the DNA of cancer cells. These proteins normally act in healthy white blood cells to fight infection by causing harmful mutations in the DNA of viruses. However, APOBEC3 proteins can cause mutations in human DNA which may contribute to cancer.