Methodology: IHC

Clinical Significance:
Identifies neural cell adhesion molecule (NCAM), a cell surface-associated protein expressed by NK cells and a subset of activated T cells, in addition to a variety of neuroectodermally-derived structures. CD56 is expressed on the majority of NK cell neoplasms, and on a subset of T cell neoplasms. CD56 is aberrantly expressed by myeloid blasts, granulocytes, and/or monocytes in a subset of acute myeloid leukemias and myelodysplastic/myeloproliferative syndromes, and by the neoplastic plasma cells in a large subset of multiple myelomas. Finally, CD56 is strongly expressed by small blue round cell tumors of neuroectodermal origin, and by neuroendocrine carcinomas. Subcellular Localization: Membranous

Organ: Brain/CNS

Disease State: Small, Blue, Round Cell Tumors

CPT Code(s): 88342 or 88341 (reference only; CPTs may vary)

Turnaround Time: Within 1-2 business days of receipt

Schedule: Monday - Friday

Specimen Requirements:
• Formalin-fixed, paraffin-embedded (FFPE) tissue block or cell block - OR - • 1 unstained slide for each test requested plus 3-4 additional unstained slides cut at 4µm