1. Specific Aim 1 is to describe the PLCO biospecimen collection, processing, and storage procedures. This includes the blood samples obtained from screened arm participants, buccal cells obtained from control arm participants, and tissue samples obtained for creation of tissue microarrays. The processes that the individual screening centers and central repository undertook will be compared and contrasted against the SOPs that were developed for the PLCO Trial. 2. Specific Aim 2 is to describe PLCO biospecimen data management procedures. This includes: a) the QC procedures to ensure that accurate biospecimen related data were entered into the appropriate systems, and b) description of the biospecimen variables, such as pre-analytic and processing variables, that are maintained as part of the PLCO Trial. 3. Specific Aim 3 is to provide information regarding the past and current uses of PLCO biospecimens in order to give insight to the potential utility of the PLCO biospecimens in a wide range of potential studies. In addition, we will include a brief description of how the samples are accessed by investigators and tracked by the coordinating center; another PLCO proposal (2008-007) deals with a more in depth analysis of the PLCO and PLCO EEMS review and approval processes. Depending on the amount of data obtained, we will examine how the pre-analytic variables (aim 1) may affect biospecimen integrity and their use in various assays; if we have sufficient amount of data, we will submit a separate addendum to describe the analytical approach proposed to examine the relationship of pre-analytic variables to specimen integrity/utility.