CK5 is more sensitive than CK5/6 in identifying the "basal-like" phenotype of breast carcinoma.
Multiple immunohistochemical stains, including cytokeratin (CK)5/6, are used in a panel format to identify "basal-like" carcinomas. We set out to determine the sensitivity and specificity of the CK5 antibody (clone XM26) and compared its expression with that of CK5/6 (clone D5/16B4) in a variety of breast carcinoma cases. The study was performed on 3 breast carcinoma tissue microarrays (TMAs). TMA-1 consisted of 59 consecutive breast carcinoma cases. TMA-2 (n = 16) and TMA-3 (n = 11) consisted of basal-like breast carcinomas previously characterized morphologically and immunohistochemically at our institution. Of the 86 total cases, 20 were positive for CK5 and CK5/6, 14 were positive for CK5 only, and 52 were negative for both. The sensitivity of CK5 for identifying basal-like tumors was 97% compared with 59% for CK5/6. Both antibodies had comparable specificity of more than 95%. For positive cases, the percentage and intensity of staining was much higher with CK5 than with CK5/6 (P = .0001).
Department of Pathology, Magee-Womens Hospital of the University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
Rohit
R
Bhargava
Sushil
S
Beriwal
Kim
K
McManus
David J
DJ
Dabbs
D000328:Adult; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D002280:Basal Cell Carcinoma / Q000175:diagnosis / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D053555:Keratin-5 / Q000032:analysis* / Q000276:immunology; D053553:Keratin-6 / Q000032:analysis* / Q000276:immunology; D012680:Sensitivity and Specificity
D053555:Keratin-5; D053553:Keratin-6