DISEASE CHARACTERISTICS: - Diagnosis of primary cancer at age 21 or younger - In active follow-up by a Children's Oncology Group (COG) institution - Date of last visit or contact by a COG institution within the past 24 months - Case group - Development of one of the following key adverse events after initiation of prior cancer therapy: - Cardiac dysfunction, meeting 1 of the following criteria: - Symptomatic cardiac dysfunction, including current or previous diagnosis of congestive heart failure based on any of the following clinical criteria: - Pulmonary and/or peripheral edema - Dyspnea - Orthopnea - Fatigue - Hepatomegaly - Asymptomatic cardiac dysfunction - Ejection fraction < 40% on echocardiogram OR MUGA and/or fractional shortening < 28% on echocardiogram without clinical symptoms - Myocardial infarction, meeting 1 of the following criteria (closed to accrual as of 6/5/06): - Definite ECG changes - Typical, atypical, or inadequately described symptoms AND probable ECG, AND abnormal enzymes, including creatine kinase MB - Typical symptoms AND abnormal enzymes, including creatine kinase MB, AND ischemic ECG, non-codable ECG, or ECG not available - Ischemic stroke, meeting the following criteria: - Fixed neurological deficit lasting more than 24 hours - Confirmed by CT scan or MRI within 7 days of onset of symptoms - No subarachnoid or intracerebral hemorrhage, transient ischemic attacks, or amaurosis fugax - Avascular necrosis, meeting the following criteria: - Clinical symptoms of joint pain, joint stiffness, or decreased range of motion - Confirmed by plain radiographs, CT scan, MRI, or bone scan - Subsequent malignant neoplasm, meeting the following criteria: - Histologically distinct neoplasm developing in patients treated for a primary cancer - Confirmed by an institutional pathology report - Control group - No clinical evidence of any of the following: - Cardiac dysfunction - Myocardial infarction (closed to accrual as of 6/5/06) - Ischemic stroke - Avascular necrosis - Subsequent malignant neoplasm PATIENT CHARACTERISTICS: Age - 21 and under at diagnosis, any age at study entry Performance status - Not specified Life expectancy - Not specified Hematopoietic - Not specified Hepatic - Not specified Renal - Not specified Cardiovascular - See Disease Characteristics PRIOR CONCURRENT THERAPY: Biologic therapy - Not specified Chemotherapy - Not specified Endocrine therapy - Not specified Radiotherapy - Not specified Surgery - Not specified Other - No prior allogeneic (non-autologous) hematopoietic cell transplant