Cytokeratin 5/6 (CK5/CK6) antibodies are for example applied to identify basal cells or myoepithelial cells for ruling out invasive breast and prostate cancer, to detect squamous cell origin in poorly differentiated carcinomas [6], and to distinguish epithelioid mesothelioma (mostly CK5/6 positive) from lung adenocarcinoma (mostly CK5/6 negative) [5]. This evidence concerns the gene KRT5 and prostate carcinoma.