Collection of Blood From Patients With Cancer, Other Tumors, or Tumor Predisposition Syndromes for Genetic Analysis

Background: * Genetic polymorphisms in drug-metabolizing enzymes, transporters/receptors might affect an individual's response to drug therapy. * Inter-individual differences in efficacy and toxicity of antitumor agents are especially important given the narrow therapeutic index of these drugs. * During analysis of investigational agents, inter-individual variation in pharmacokinetics (PK) and pharmacodynamics (PD) is most often noted. Genetic variation in genes encoding proteins that regulate or mediate the metabolism and transport of drugs often account for some of the wide variation seen in PK/PD, and ultimately the response to, and toxicity from, pharmaceutical agents. * The administration of probe substrates can be used to determine the phenotype of enzymes and transporters responsible for drug disposition, providing a useful tool to better understand the cause of unexpected AEs or toxicities of clinical trial participants. Objectives: -Explore potential associations between genetic variants discovered with Pharmacoscan involved in inter-individual differences in drug disposition versus the pharmacokinetics, pharmacodynamics of pharmaceutical agents. Eligibility: -Any individual currently enrolled on IRB approved NIH Intramural Research Program (IRP) therapeutic clinical trials. Design: * Exploratory study with a planned accrual of 1,100 participants. * Genomic DNA extracted from blood samples collected from participants (participants with leukemia will have cheek swab samples collected) will be analyzed. * In cases where participants carry genetic variants that related to poor outcome or significant toxicity on a given drug, clinical recommendations will be provided where specific instructions are available in the package insert. * The association between variants in Pharmacoscan-covered genes will be correlated with PK/PD and clinical outcomes such as response and/or toxicity. * Genotyping and/or phenotyping probe administration will be used to identify potential genetic variants with unknown or poorly defined drug interactions, including genetic variants with unknown metabolic phenotype and drugs with poorly defined metabolic pathways in the literature. * The Clinical Pharmacology Program (CPP) will measure the plasma concentration of enzyme or transporter phenotyping probe substrates (or send the sample out to a third party if the assay is commercially available) in select participants enrolled on clinical trials at the CCR.