Fig. 3

Pathology of endoscopic biopsies. (A) Poorly differentiated adenocarcinoma was confirmed on biopsy of the thickened pylorus. (B–D) The tumor was diagnosed as primary gastric adenocarcinoma based on immunohistochemistry: CDX2-positive, GATA3-negative, and MUC5AC-positive. (E) Poorly differentiated adenocarcinoma was also confirmed on biopsies of the depressed lesions in the gastric corpus. (F–H) The tumor was diagnosed as metastatic breast cancer based on immunohistochemistry: CDX2-ngeative, GATA3-positive, and MUC5AC-negative (the brown areas in the MUC5AC stain are artifacts; the cytoplasm is stained instead of the nucleus)