Patients enrolled in this study will not receive investigational therapy. Any treatments rendered will be standard and based on appropriate medical care. Should a patient become eligible for an experimental therapy protocol, the normal process of enrollment and informed consent will be followed.

This protocol will enable the Pediatric Branch to follow selected children with cancer or HIV infection who are not immediately eligible for protocol enrollment but who are likely, within the next year, to become candidates for protocol entry. It will also enable the Pediatric Branch to follow children who present with either clinical findings that constitute important educational experiences for the NCI trainees or who have unique or unusual medical problems that are likely to benefit from the research expertise of the NCI.

Children with cancer (or a precancer syndrome) or HIV infection, between the age(s) of 3 months to 30 years, who are evaluated by the Pediatric Branch and are found to be not immediately eligible for an ongoing protocol but are likely to become a candidate for a future protocol.

Children with cancer (or a precancer syndrome) or HIV infection, who present with disease manifestations of special interest to Pediatric Branch investigators, because they are likely to shed light on disease.

Patients who, when evaluated by the Branch, are determined to likely never become eligible for a Pediatric Branch protocol are not eligible for this protocol.

No patients younger than 3 months of age or older than 30 years of age are eligible for this protocol.