Reply to “Anti-cytokeratin CAM5.2 Recognized CK8 Mainly, but not CK18: Comment on ‘Early Assessment of Axillary Response with ¹⁸F-FDG PET/CT During Neoadjuvant Chemotherapy in Stage II–III Breast Cancer: Implications for Surgical Management of the Axilla. Ann Surg Oncol. 2013;20(7):2227–35’”

To the Editors:

We agree with Chao and Han that uncertainty exists about the cytokeratins recognized by the CAM5.2 antibody in immunohistochemistry.1,2 It has become clear from immunoblot experiments that CAM5.2 is specific for cytokeratin 8 and to a lesser extent for the closely related cytokeratin 7, but not for cytokeratin 18.3,4 Nevertheless, CAM5.2 is generally accepted to be suitable for detection of metastatic breast cancer in (sentinel) lymph nodes because almost all breast carcinomas also strongly express cytokeratin 7.