Bone marrow section showing acute myeloid leukemia with a c-KIT D816V mutation. (A) The hematoxylin and eosin–stained bone marrow biopsy shows replacement by blasts with prominent nucleoli and eosinophilic cytoplasm (shown at ×400 magnification). (B) c-KIT D816V mutation detected in bone marrow. DNA was extracted from bone marrow and exon 17 of c-KIT was amplified by polymerase chain reaction (PCR). The PCR product was purified and analyzed by standard direct DNA sequencing procedures using an Applied Biosystems 3730 DNA Genetic Analyzer. A missense A>T mutation is detected at position 2447, which results in a D816V amino acid change.