Background: Pan-cytokeratin CK(Pan) mainly markers keratinized epithelium, stratified squamous epithelium, stratified epithelium, proliferating keratinized cells, and monolayer epithelium. It is used in squamous cell carcinoma (including spindle variant), various adenocarcinomas (including adrenal carcinoma, hepatocellular carcinoma), transitional cell carcinoma, small cell carcinoma, malignant mesothelioma, germ cell tumors (except seminoma), some synovial sarcoma, and other types of adenocarcinomas. Leiomyosarcoma can be positively labeled. EMA and CEA can be used in the differential diagnosis of epithelial tumors and non-epithelial tumors, and can also be used in the study of various cancers.