We propose a generic protocol for use in obtaining blood, urine, saliva and dust samples anonymously from adult volunteers for use in laboratory assay evaluation. The samples will be used to determine if new tests are sufficiently valid and precise to be used in epidemiologic studies and for quality control purposes. In epidemiologic studies involving the storage and analysis of laboratory specimens, it is essential to evaluate the performance of available assays in the target population and to actively assess the impact of storage and handling on the quality of samples and laboratory analyses. Specifically, it is essential to 1) demonstrate that an assay is sufficiently reproducible and stable over time such that differences in levels among individuals in the target population can be detected; 2) evaluate assay reliability by sending blinded anonymous samples along with study samples to testing labs for quality control purposes; 3) test proposed laboratories or methods by using replicate samples from the target population in order to choose the laboratory or method with the greater precision; and 4) assess how sample collection, handling, and storage procedures affect measured levels of specific analytes to allow for informed decisions about whether to proceed with a specific analysis. Under this protocol, assays could include evaluation of immunologic parameters, genes and gene products, peptides, proteins, hormones, lipids, viability of cells, evaporation and dilution effects, chemical toxins and their metabolites, micronutrients, metals, and more. For some samples, lymphocytes will be extracted for use in studies of DNA damage and for creation of cell lines. Assays will be performed on lymphocytes prior to freezing and the remaining sample will be cryopreserved to facilitate validation of studies involving frozen lymphocytes and/or immortalized cells. Samples to be collected will include blood and/or urine and/or household dust and/or saliva samples. Although this protocol may be used to evaluate assays for other studies, the primary purpose for this proposal is to provide quality control samples for the Sister Study. Since it is important to collect samples from the target population, this protocol covers collection of samples from non-pregnant women age 35-74 years who have not been diagnosed with breast cancer. The samples will be collected and stored using protocols developed for the Sister Study. This protocol covers two types of collection from non-pregnant adult women. Up to 200 volunteer women will be asked to provide a one-time collection of one blood sample (up to 45 ml) and one urine sample. A subset may be asked to provide a dust sample and/or saliva sample for assay evaluation or develoment purposes. A second group of up to 100 non-pregnant volunteer women will be asked to provide blood (45 ml), urine, household dust, and possible saliva- on as many as seven occasions over a period of approximately one year.