Aleksandra Klimczak is the Head of the Laboratory of Biology of Stem and Neoplastic Cells at the Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences. Her scientific activity is associated with a wide range of research related to mesenchymal stem cell biology, regenerative medicine, and transplant immunology, both in experimental models and in clinical applications. Earlier research by Prof. Klimczak, related to transplant immunology, significantly contributed to the understanding of the mechanisms of immune tolerance in cell transplantation and in composite tissue allografts. Currently, Professor Klimczak is conducting intensive research on the biology of somatic mesenchymal stem cells residing in the tissues of an adult organism in the context of using their biological potential in regenerative medicine. Moreover, she is also conducting research on the biology of cancer stem cells. Currently, she is the author and co-author of over 120 publications, including nine book chapters and over 300 conference abstracts, mainly presented at international conferences.