Inclusion Criteria:

* Enrollment must occur within 6 months of initial disease presentation OR within 6 months of refractory disease, disease progression, disease recurrence, second or secondary malignancy, or post-mortem
* Patients previously enrolled on ACCRN07 are eligible to enroll on Tracking Outcome, Registry and Future Contact components of APEC14B1 any time after they reach age of majority
* Patients with a known or suspected neoplasm that occurs in the pediatric, adolescent or young adult populations are eligible for enrollment as follows:

* All cancer cases with an International Classification of Diseases for Oncology (ICD-O) histologic behavior code of one "1" (borderline), two "2" (carcinoma in situ) or three "3" (malignant)
* All neoplastic lesions of the central nervous system regardless of behavior, i.e., benign, borderline or malignant
* The following other benign/borderline conditions:

* Mesoblastic nephroma
* Teratomas (mature and immature types)
* Myeloproliferative diseases including transient myeloproliferative disease
* Langerhans cell histiocytosis
* Lymphoproliferative diseases
* Desmoid tumors
* Gonadal stromal cell tumors
* Neuroendocrine tumors including pheochromocytoma
* Melanocytic tumors, except clearly benign nevi
* Ganglioneuromas
* Subjects must be =< 25 years of age at time of original diagnosis, except for patients who are being screened specifically for eligibility onto a COG (or COG participating National Clinical Trials Network \[NCTN\]) therapeutic study, for which there is a higher upper age limit
* All patients or their parents or legally authorized representatives must sign a written informed consent and agree to participate in at least one component of the study; parents will be asked to sign a separate consent for their own biospecimen submission

* If patients or their parents or legally authorized representatives have not signed the Part A subject consent form at the time of a diagnostic bone marrow procedure, it is recommended that they initially provide consent for drawing extra bone marrow using the Consent for Collection of Additional Bone Marrow; consent using the Part A subject consent form must be provided prior to any other procedures for eligibility screening or banking under APEC14B1