About the Author: Shan-Rong Shi, MD, is professor of clinical pathology at the Keck School of Medicine of the University of Southern California. He is the Associate Editor of The Journal of Histochemistry and cytochemistry, he is on the Editoral Board of Applied Immunohistochemistry and Molecular Morphology and is also on the Overseas Editorial Board of the Chinese Journal of Pathology. Dr. Shi is the ineventor of the antigen retrieval (AR) technique. Clive R. Taylor, MD, PhD, is Senior Associate Dean, Professor and Chairman of Pathology at the Keck School of Medicine. Dr. Taylor is Editor in Chief of Applied Immunohistochemistry and Molecular Morphology. Dr. Taylor is a world renowned expert in immunohistochemistry and clinical pathology.