Cytokeratin 5 / 6 are high molecular weight cytokeratin (58 kDa and 56 kDa), which are expressed in basal cells and echinoderm cells of the skin, some basal cells of the prostate and other single layer glandular epithelium. They are mainly used for the differential judging of mesothelioma and adenocarcinoma. They can be used in the differential judging of benign and malignant prostatic lesions in combination with 34bae12 and P504S.