SOX2 and adenocarcinoma: Although both components were NKX2-1-negative, markers of gastric differentiation were restricted to the adenocarcinoma component, and markers of squamous differentiation (including ΔNp63 and cytokeratins 5 and 14 (CK5 and CK14), but not SOX2) were selectively expressed in the SCC component (Figure 4B and Figure 4—figure supplement 1C).