Blood and lymph node cancers can begin in either the lymphatic tissues (as in the case of lymphoma) or in the bone marrow (as with leukemia and myeloma), and they all are involved with the uncontrolled growth of white blood cells. There are many subtypes of these cancers, e.g., chronic lymphocytic leukemia and non-Hodgkin lymphoma. Since there is evidence that these cancers cluster in families, this study aims to understand how genetics and environmental exposures contribute to the development of these cancers.