Human colon cancer screened with Ms anti-PCNA requiered HIER buffer Citrate pH6 (B21C-100) and visualized with DAB Ni (C10-12) resulting in a black nuclear stain. This image is part of a triple stain showing MsxSMActin staining in red using GBI permanent Red (C13-18) and RbxCEA staining in brown using DAB (C09-12). Secondary and chromogens were supplied in TS301B