The Ki-67 nuclear antigen is associated with cell proliferation and found throughout the cell cycle; though not in G0 phase (1,2). The assessment of Ki-67 proliferation in breast cancers has shown the Ki-67 labelling index is an important predictor of survival (3). Cytokeratin (CK) 7 is expressed in epithelial cells of the ovary, lung and breast. Rabbit monoclonal CK7 (Clone BC1) is often used in conjunction with CK20 and CDX-2 in distinguishing pulmonary, ovarian and breast carcinomas (CK7+) from most colon carcinomas (CK7-) (4). Clones EP17 and EP30 recognize CK8 and CK18, both of which recognize low molecular weight intermediate filament proteins. In normal tissues, CK8/18 recognizes all simple and glandular epithelium (5). In neoplastic tissues, CK8/18 may prove useful for the identification of most adenocarcinomas and some squamous cell carcinomas. CK8/18 expression patterns may also aid in the classification of tumors of unknown origin and poorly differentiated carcinomas (5-7). CK8/18 rabbit monoclonal may be useful as a staining mask in a multiplex stain with mouse monoclonal antibody Ki-67.
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2. McCormick D, et al. Detection of the Ki-67 antigen in fixed and waxembedded sections with the monoclonal antibody MIB1. Histopathology. 1993 Apr;22(4):355-60.
3. Pinder SE, et al. Assessment of the new proliferation marker MIB1 in breast carcinoma using image analysis: associations with other prognostic factors and survival. Br J Cancer. 1995 Jan;71(1):146-9.
4. Qi W , Tacha D. Characterization and applications of a newly developed rabbit monoclonal antibody to cytokeratin 7 (CK7) for immunohistochemistry. Appl Immunohistochem Mol Morphol. 2009 May;17(3):233-8.
5. Moll R, Divo M, Langbein L. The human keratins: biology and pathology. Histochem Cell Biol. 2008 Jun;129(6):705-33.
6. Dabbs DJ. Diagnostic Immunohistochemistry. Philadelphia,PA: Churchill Livingstone, 2002.
7. Makino T, et al. Cytokeratins 18 and 8 are poor prognostic markers in patients with squamous cell carcinoma of the oesophagus. Br J Cancer. 2009 Oct 20;101(8):1298-306.
8. Center for Disease Control Manual. Guide: Safety Management, NO. CDC-22, Atlanta, GA. April 30, 1976 “Decontamination of Laboratory Sink Drains to Remove Azide Salts.”
9. Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline-Fourth Edition CLSI document M29-A4 Wayne, PA 2014.