Patients with cancer are frequently treated with chemotherapy and/or radiation therapy. A small subgroup of these patients develops a type of leukemia called Therapy-related Acute Myeloid Leukemia (tAML) as a complication. It is a deadly disease with more than 90% of patients dying within 5 years. Based on our recent work, we think the chemotherapy exposure to normal blood stem cells causes the stem cell to undergo rapid aging; then, the aged stem cells turn into cancer. The proposed study is to test this idea and the process to discover how aging of blood stem cells causes leukemia.