This gene encodes a cell adhesion protein from the immunoglobulin superfamily involved in cell-to-cell and cell-matrix interactions during development It regulates neurogenesis neurite outgrowth and cell migration in the nervous system and supports the expansion of T lymphocytes B lymphocytes and natural killer (NK) cells in immune surveillance It also plays a role in signal transduction by interacting with fibroblast growth factor receptors N-cadherin and components of the extracellular matrix activating signaling pathways like FYN-FAK MAPK and PI3K A prominent isoform CD56 is implicated in myeloproliferative disorders like acute myeloid leukemia CD56 expression is linked to disease progression with higher levels correlating to lower survival in leukemia patients and severe COVID-19 associated with decreased CD56 NK cells Alternative splicing produces multiple isoforms