CD56 (CD56 Antigen, Cell Adhesion Molecule Neural 1, MSK39, Neural Cell Adhesion Molecule 1, NCAM 1, NCAM1, NCAM-1, N-CAM-1, NCAM)

CD56 is involved in intercellular adhesion and plays a role in outgrowth of neurites and the development of the nervous system. Several other isoforms have been identified which are expressed in a developmental and tissue specific pattern. At the international Workshop on SCLC antibodies 123C3 has been categorized as cluster 1 antibody (Stahel et al 1994). Most importantly, 123C3 can be used on routing formalin fixed paraffin section after retrieval. All cells in small cell carcinomas and carcinoids of the lung are strongly positive for 123C3. A minority of cases of other major types of lung carcinoma are sometimes positive as well: however this positivity is generally weak and focal. Adenoid cystic carcinomas of bronchial glands are strongly positive. Neuroblastoma's and Wilms tumors also usually stain strongly positive. In non small lung cell carcinomas, 123C3 staining has been associated with more advanced stage and a decreased survival after surgery (Kibbelaar et al. 1991). Positive staining with other tumors, include medullary thyroid carcinomas and some ovarian tumors. CD56 is a marker for natural killer: 123C3 can be used to distinguish NK cells from other haematopoietic cell populations. Although expression of CD56 is uncommon amoung lymphomas, this feature has defined a distinctive and important category of lymphoma: the putative natural killer (NK) cell lymphoma, which shows a predilection for the upper aerodigestive tract, skin, skeletal muscle and other extranodal sites and pursues an agressive clinical couse. Furthermore, this antibody can be used to support diagnosis of lymphoma or to detect residual disease for cases of CD56 positive T/NK -cell lymphoma in which the neoplastic lymphoid cells are small and show minimal atypia, especially in small biopsies. Applications: Suitable for use in Immunofluorescence and Immunohistochemistry. Other applications not tested. Recommended Dilution: Immunohistochemistry: 1:10 Formalin fixed paraffin sections should be pretreated in microwave or pressure cooker. Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.