2 different protocols from very different antibodies. The Abcam antibody is a polyclonal, whereas the Thermo D11915 is a monoclonal but both have nearly identical results. Abcam’s antibody ab197942 states “for use on IHC-P(paraffin)” and positive controls listed on the data sheet are human liver cancers and human gastric cancers. The Thermo Fisher antibody lists “flow cytometery and immunofluorescence” only. These antibodies were tested using Formalin Fixed Paraffin Embedded(FFPE) human tissues.