Twenty human keratins are resolved with two-dimensional gel electrophoresis into acidic (pI 6.0) subfamilies. This antibody cocktail recognizes acidic (Type I or LMW) and basic (Type II or HMW) cytokeratins, with 67kDa (CK1); 64kDa (CK3); 59kDa (CK4); 58kDa (CK5); 56kDa (CK6); 55kDa (CK7); 52kDa (CK8); 56.5kDa (CK10); 53kDa (CK13); 50kDa (CK14); 50kDa (CK15); 48kDa (CK16); 46kDa (CK17); 45kDa (CK18) and 40kDa (CK19). Many studies have shown the usefulness of keratins as markers in cancer research and tumor diagnosis. KRT-PAN is a broad-spectrum anti pan-cytokeratin antibody cocktail, which differentiates epithelial tumors from non-epithelial tumors e.g. squamous vs. adenocarcinoma of the lung, liver carcinoma, breast cancer, and esophageal cancer. It is useful in characterizing the source of various neoplasms and to study the distribution of cytokeratin containing cells in epithelia during normal development and during the development of epithelial neoplasms. This antibody stains cytokeratins present in normal and abnormal human tissues and shows high sensitivity in the recognition of epithelial cells and carcinomas.