NKX2.2

Formalin-fixed, paraffin embedded tissue block or cell block, or 1 unstained charged slide for each test requested plus 3-4 additional unstained slides cut at 4 microns. Adequate space on each slide for control tissue is required.

NKX2.2 gene is an important target of the EWS-FLI-1 fusion protein, and is up-regulated in Ewing's sarcoma/primitive neuroectodermal tumor (PNET). Antibody to NKX2.2 is thus a useful immunohistochemistry marker in the diagnosis of Ewing's sarcoma/PNET; however, it is also known to be positive in olfactory neuroblastoma and a subset of small cell carcinoma, synovial sarcoma, and melanoma. NKX2.2 may also serve as a novel marker for neuroendocrine differentiation, supplementing the conventional neuroendocrine markers, such as chromogranin A and synaptophysin. NKX2.2 is reported to be positive in a high percentage of gastrointestinal and pancreatic neuroendocrine tumors (carcinoid and islet cell tumors) but negative in bronchopulmary carcinoids.