Li-Fraumeni Syndrome (LFS) and Li-Fraumeni-like (LFL) Syndrome are cancer predisposition syndromes due to germline aberrations in the TP53 gene. Patients with classical LFS have a lifetime malignancy risk between 80-90%, with 21% of those cancers occurring by the age of 15 years. There are established guidelines for screening patients with LFS that have led to earlier detection and treatment of cancer in this population. There are a number of important issues facing patients identified to have germline TP53 variations. First, with the advent of massively parallel sequencing, increasing numbers of patients are now being identified with a wide range of clinical phenotypes associated with germline TP53 mutations, and the natural history of these patients is less well understood. Second, surveillance for malignancy in LFS and other TP53-associated syndromes involves frequent laboratory and radiologic studies that are imperfect measures of disease onset; therefore, more specific, less invasive biomarker-driven screening methods are needed. Finally, studies to date have not yet identified whether tumors which form in LFS or other germline TP53-associated tumors have unique aberrations or signatures that could be exploited in precision medicine treatment of these patients. In order to study these important issues in LFS, this protocol will establish a TP53 Clinical Database and Biobank. The Investigator plans to use this biobank to study genotype-phenotype correlations in patients with LFS and other germline TP53-associated syndromes, mechanisms of tumor formation, and novel methods of cancer screening in this high risk population.