Olga Zajac-Spychala is an assistant professor at the Department of Pediatric Oncology, Hematology, and Transplantology of the Medical University of Warsaw, Department V of Hematology and Oncology for Older Children. She is the coordinator of a nationwide project on infectious complications in patients treated for cancer or undergoing hematopoietic stem cell transplantation and the National Coordinator of the treatment of acute leukemia with mixed phenotype.