RecruitingUNC Childhood, Adolescent, and Young Adult Cancer CohortPurpose: This study aims to create a registry of childhood, adolescent, and young adult patients with cancer (\<40 years-old at cancer diagnosis), entitled the 'UNC Childhood, Adolescent, and Young Adult Cancer Cohort' (UNC-CAYACC). This resource will serve to support cancer outcomes research among pediatric and young adult cancer patients with a primary focus on enrolling patients treated as adolescents or young adults (AYAs, 15-39 years). Procedures: As appropriate for age, participants will complete physical and cognitive functional assessments; questionnaires to assess health-related quality of life and other patient-reported outcomes; will undergo body composition and anthropometric measurements; and will be asked to provide biospecimens for biobanking. Assessments will be collected (as possible) at diagnosis, during active treatment, following treatment completion, and annually in survivorship to assess outcomes throughout the treatment and survivorship trajectory. Sociodemographic and clinical information such as cancer treatment modalities and cumulative doses will be collected by medical record abstraction. Participants will be eligible to enroll at any time from diagnosis through survivorship. This registry will provide data to better understand the manifestations of accelerated aging and key contributing factors among children, adolescents, and young adults with cancer.