Anti-Cytokeratin CAM5.2 Monoclonal Antibody Reacted with Both Cytokeratin 7 and 8, but not Cytokeratin 18. Comment on: Hepatocellular Carcinoma Metastatic to the Gingiva as a First Manifestation of Hepatocellular Carcinoma. J Maxillofac Oral Surg (JMOSI), Published on Line: 25 February 2011; DOI: 10.1007/s12663-011-0187-z.

Abstract

We read with great interest the contribution by Dr. Terada T regarding the study, entitled ‘‘Hepatocellular carcinoma metastatic to the gingiva as a first manifestation of hepatocellular carcinoma’’ [1]. The author presented a good case report, and implemented a comprehensive discussion. However, there was a typo in the ‘‘Abstract’’ section that CAM5.2 was misspelled ‘‘CAM6.2’’. Additionally, this article contains a wrong identification in the second paragraph of the ‘‘Case Report’’ section that I believe, may misguide the readers. Dr. Terada T may have inadvertently annotated that ‘‘CAM5.2 reacted with both cytokeratin 8 and 18’’. We would like to explain that the anti-cytokeratin CAM 5.2, clone CAM 5.2, is marketed by Becton–Dickinson Biosciences (Franklin Lakes, NJ). This clone primarily recognizes both human cytokeratin proteins 7 and 8, whereas it is lesser specific to cytokeratin 7. Both peptides are found in most epithelial cells, with the exception of stratified squamous epithelium [2]. As a result, it is clarified that anti-cytokeratin CAM5.2 monoclonal antibody is a marker for cytokeratin 7 and 8 but not for cytokeratin 18. This letter can help us elucidate the critical points that CK8/18 is not equivalent to CAM5.2; as well as anticytokeratin CAM5.2 should not be mistaken for monoclonal antibody CK8/18 [2, 3]. However, this finding does not detract from the study results and impressions that hepatocyte paraffin-1 (HepPar-1) (OCH1E5, Dako) is a relatively specific marker of hepatocytes and hepatocellular carcinoma. Hepatocellular carcinoma can manifest as small gingival tumors, and careful hematoxylin-eosin stain and immunoreactive HepPar-1 are useful in the diagnosis of hepatocellular carcinoma in extrahepatic metastatic sites [1].