Patient has ALL (or a prior history of Non-Hodgkin Lymphoma) at first or subsequent marrow relapse with greater than or equal to 25% blasts in the bone marrow and/or peripheral blood
Prior enrollment in a COG ALL trial at initial diagnosis is not required
Enrollment in a COG therapeutic trial at relapse is not required
No systemic anti-leukemic treatment has been administered for the current relapse
Patients are eligible if they have relapsed while receiving therapy
Age: <31 years of age at the time of initial diagnosis of ALL
Adequate bone marrow or peripheral blood specimens must be sent for eligibility