CAM5.2 is not identical to cytokeratins 8 and 18.

To the Editor In an article entitled “Prognostic Significance of CXCL12 Expression in Patients With Colorectal Carcinoma,”1 we found that the authors may have inadvertently annotated CAM5.2 as cytokeratins (CKs) 8 and 18 by using a pair of square brackets to reference some reports, which might suggest that CAM5.2 is identical to CK8 and CK18. Becton Dickinson (BD) Biosciences revised the data sheet for CAM5.2 (BD 23-3190-01) in July 1997 that lists the primary reactivity as CK8 and, to a lesser extent, CK7. In addition, it shows no reactivity with CK18 or CK19.2-5 However, we can still find several current reports that improperly infer that CAM5.2 is the same as CK8/CK18. We want to comment that anticytokeratin CAM 5.2 reagent (BD), which is composed of the clone CAM5.2, reacts with human CK intermediate filament proteins of 48 kDa and 52 kDa, identified as CK7 and CK8, respectively.2-5 This letter can help to clarify the critical point that CAM5.2 is not identical to CK8 and CK18 and anticytokeratin CAM5.2 reagent does not stand for antibodies CK8 and CK18.2-9 Jeng-Dong Hsu, DDS, MS Departments of Pathology Chung-Chin Yao, MD, PhD Departments of Surgery Chung-Shan Medical University Hospital and School of Medicine, Chung Shan Medical University Taichung, Taiwan Lih-Wen Han Clinical Medicine Program Peking University Health Science Center Beijing, People’s Republic of China Chih-Ping Han, MD, PhD Department of Obstetrics and Gynecology and Clinical Trial Center Chung-Shan Medical University Hospital and Institute of Medicine Chung-Shan Medical University Taichung, Taiwan