This MAb recognizes the 56.5kDa (CK10), 50kDa (CK14), 50kDa (CK15), 48kDa (CK16), 40kDa (CK19) keratins of the acidic (Type I or LMW) subfamily. Twenty human keratins are resolved with two-dimensional gel electrophoresis into acidic (pI <5.7) and basic (pI >6.0) subfamilies. The acidic keratins have molecular weights (MW) of 56.5, 55, 51, 50, 50 , 48, 46, 45, and 40kDa. Many studies have shown the usefulness of keratins as markers in cancer research and tumor diagnosis.