The Histopathology Core will be responsible for supporting all the histological, immunocytochemical, and in situ hybridization methodology for three research projects in this application. The histological analysis of a skeletal tissue provides a unique challenge due to its mineralized nature and virtual impenetrability to stains, antibodies, and probes. Thus, the dedication of an independent core unit under the direction of an experienced pathologist is of paramount importance for the completion of the proposed work. Described within this Core, outlined are the methods and pitfalls associated with working with skeletal tissues as well as a comprehensive bibliography demonstrating the ability of the staff to solve problems in the analyses of the tissues. All expenses related to tissue and cell processing for the 3 research projects will be administered through the Histopathology Core.