Specificity: This antibody recognizes two proteins (185kDa & 145kDa), identified as two isoforms of neural cell adhesion molecule (NCAM/CD56). It is used as a tumor marker in various cancers such as NK lymphomas and Merkel cell carcinoma. NCAM is expressed on most neuroectodermal derived lines, tissues, and neoplasms such as retinoblastoma, medulloblastoma, astrocytoma, and neuroblastoma. It is also expressed on some mesodermally derived tumors such as rhabdomyosarcoma and also on natural killer cells.