MUC5AC and carcinoma: Dysplasia and indeed carcinoma can show gastric and intestinal differentiation markers.7 Dysplasia may arise through mutational events in stem cells: hence, dysplasia developing in TFF1+/MUC5AC+ or in TTF3+/MUC2+ committed stem/progenitor cells may account for the origin of the dysplasia in the stem cell zone and also for the several differentiation patterns described.7