Pancytokeratin

Pancytokeratin:PanCytokeratin AE1/AE3

Because of its broad reactivity, cytokeratin AE1/AE3has been referred to as a "pancytokeratin" by some pathologists. Cytokeratin AE1/AE3 is a very commonly used reagent in diagnostic immunohistochemistry.As its name implies, cytokeratin AE1/AE3 is a mixtureof two different clones of anti-cytokeratin monoclonalantibodies, AE1 and AE3. Both of these individualclones detect certain high and low molecular weightkeratins. AE1 detects the high molecular weigh tcytokeratins 10, 14, 15, and 16, and also the low molecular weight cytokeratin 19. Clone AE3 detectsthe high molecular weight cytokeratins 1, 2, 3, 4, 5,and 6, and the low molecular weight cytokeratins 7and 8. By combining these two reagents, a singlereagent with a broad spectrum of reactivity againstboth high and low molecular weight cytokeratins isobtained. Notably absent from this cocktail is reactiv-ity to cytokeratin 18, one of the simple epithelialcytokeratins (along with cytokeratin 8), that isexpressed in hepatoma and many other carcinomas. As pointed out before ,b ecause of its broad reactivity, cytokeratin AE1/AE3has been referred to as a "pancytokeratin" by some pathologists. However, since it does not detect allcytokeratins (such as 17 and 18), it is not really a pan-cytokeratin reagent. Personally, I think the use of theterm "pancytokeratin" in diagnostic reports is counter-productive, since if not further qualified, this term doesnot provide information on the particular clones pres-ent within the reagent used, information that can be ofcritical importance in a number of differential diag-nostic situations. In addition, I fear that some pathol-ogists May Be lulled into a false sense of security byassuming that a negative “pancytokeratin” stain rules Rodney T. Miller, M.D., Director of Immunohistochemistry, 2003/ref>