Morphology of selected primary patient tumors and the corresponding patient-derived xenograft. A) H&E-stained sections of original patient material and B) first passage xenograft tumors (p1, lower row) demonstrate overall conserved histological features. C) CK-19 staining using human antigen specific antibody on xenograft tumors. D-E) As for panels A-B, for EAC tumors and xenografts. F) CK-19 staining on EAC PDX tissue. G) Pan-cytokeratin staining on EAC PDXs. Scale bar; 200 μm.