Manuel A. Sobrinho Simões, MD, PhD, is a Specialist in Clinical Hematology at Centro Hospitalar de S. João; an Invited Auxiliary Professor of Medicine at the Faculty of Medicine of the University of Porto; and an affiliated researcher of the Cancer Drug Resistance group at IPATIMUP. He is as a clinician, treating patients with acute and chronic hematological malignancies. His main research interest is in myeloid malignancies, with an emphasis on chronic myeloid leukemia. His work has contributed to demonstrate that molecular biomarkers of minimal amounts of residual leukemic cells are detectable in patients that have responded very well to therapy. He is particularly interested in the clinical significance of these persistent residual leukemic cells, and in the mechanisms that underlie their drug resistance and quiescence.