Methodology: IHC

Clinical Significance:
CD1a is a cell surface-associated protein expressed at the "dual-positive" stage of T cell development, which is the stage at which CD4 and CD8 are coexpressed on immature T cells in the thymus. CD1a is expressed on a subset of precursor T lymphoblastic leukemias/lymphomas corresponding to this stage of T cell development. CD1a is also expressed on the great majority of normal and neoplastic Langerhans cells.

Subcellular Localization: Membranous and cytoplasmic

Organ:

Disease State: Langerhans Cell Histiocytosis, Precursor T-Lymphoblastic Lymphoma/Leukemia (T-ALL)

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