Monoclonal antibody Cam 5.2 targeted mainly CK8, but not CK18 — Comment on: “Chromophobe renal cell carcinoma with liposarcomatous dedifferentiation - report of a unique case. Int J Clin Exp Pathol. 2010 May 5; 3 (5):534-40.”

Dear Editor:

We read with great interest the contribution by Dr. Petersson et al regarding the report, entitled “Chromophobe renal cell carcinoma with liposarcomatous dedifferentiation - report of a unique case” [1].The authors presented a good case report and implemented a comprehensive discussion; but the article contains an error in Table 1 that may misguide the readers. In the footnotes of Table 1, the authors have erroneously stated that Cam 5.2 targets CK,8,18[1].

Becton Dickinson Biosciences (Franklin Lakes, NJ) manufactured and globally marketed the anti-cytokeratin CAM5.2, which is derived from the clone CAM5.2. This clone recognizes human cytokeratin intermediate filament proteins at 48 and 52 kDa, which are identified as cytokeratins 7 and 8, respectively. Occasionally, anti-cytokeratin CAM5.2 has been mistakenly believed to recognize cytokeratins 8 and 18, since previous results by Makin et al are attributed to breakdown products of cytokeratin 8, giving smaller molecular weight fractions on im-munoblots [2]. However, Becton Dickinson Biosciences has revised the data sheet for CAM5.2 (B.D.) since 1997. It is now well known that CAM5.2 is specific for cytokeratin 8 and to a lesser extent for the closely related cytokeratin 7, but shows no reactivity with 18 [3, 4].

We believe this information is of great help to clarify the critical point that monoclonal antibody CAM5.2 recognized mainly CK8, but not CK18.