Dr. Jeffery Klco obtained his B.S. in Chemistry from Boston College. After graduation, he worked for the Howard Hughes Medical Institute in the laboratory of William G. Kaelin, MD, before moving to Washington University School of Medicine for the Medical Scientist Training Program. After receiving his MD and PhD, he completed his residency in Anatomic Pathology and his fellowship in Hematopathology, respectively. This was followed by a post-doctoral fellowship with Timothy Ley, MD, focusing on the genomics and biology of acute myeloid leukemia (AML).

In 2014, Dr. Klco started his independent research program at St. Jude Children’s Research Hospital as an Assistant Member and clinician-scientist in the Department of Pathology. He has maintained his clinical activity in the Hematopathology service and served as Medical Director from 2020 to 2023. In 2019, he was promoted to Associate Member and shortly thereafter to Director of the Division of Hematopathology and Molecular Pathology. In this capacity, he oversees the activities of clinical faculty members and clinical laboratories for immunopathology, hematopathology, and molecular diagnostics.  In 2024, he was promoted to Full Member at St. Jude. His research program is focused on identifying and functionally characterizing the genetic drivers of pediatric AML and myelodysplastic syndromes (MDS). His group has led efforts to recognize new molecular alterations, including germline mutations in SAMD9/SAMD9L and somatic alterations in BCL11B, CBFB, and UBTF. His efforts have had an immediate impact on the classification and treatment of different pediatric myeloid tumors. He mentors graduate students, clinical fellows, and postdoctoral fellows and was recognized as St. Jude Mentor of the Year in 2022.