What we are studying
In past studies of children with acute lymphoblastic leukemia (ALL), researchers have found differences in survival rates among patients in different ethnic groups. Researchers have also seen lower survival rates in children who have low blood levels of mercaptopurine (also known as Purinethol or 6-MP) during the last stage of ALL treatment (maintenance/continuation therapy). More research is needed to find out the reasons behind these differences in survival. The purpose of this study is to find out if there are differences in blood levels of mercaptopurine in children of different ethnic backgrounds.