Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF ++ Jon C. Aster, MD, PhD ++ Professor, Department of Pathology ++ Harvard Medical School ++ Staff Pathologist, Department of Pathology ++ Brigham and Women's Hospital ++ Boston, Massachusetts + ++ H. Franklin Bunn, MD ++ Professor of Medicine ++ Harvard Medical School ++ Hematology Division ++ Brigham and Women's Hospital ++ Boston, Massachusetts