In human hematopoiesis, CD56, also known as neural cell adhesion molecule 1 (NCAM1) is highly expressed in natural killer (NK) cells. In addition, NCAM1 expression was found in rare subsets of T and B lymphocytes, dendritic cells, and neural or mesenchymal stem cells. NCAM1 belongs to the immunoglobulin superfamily of adhesion molecules. NCAM1 plays an important role in the regulation of neurogenesis, neurite outgrowth, proliferation, and cell migration.