Fig. 6

Distinct anti-tumor effects of cetuximab on xenograft tumors derived from epithelial- and mesenchymal-like ESCC cells. a Time-course volumes of TE-11R (epithelial-like ESCC cells) or TE-8 (mesenchymal-like ESCC cells)-derived xenograft tumors in vivo. TE-11R or TE-8-derived xenograft tumors were treated with intraperitoneal injection of cetuximab (50 μg/kg) or vehicle on days 0, 4, and 7. Cetuximab significantly inhibited tumor growth in TE-11R-derived xenograft tumors, but not in TE-8-derived xenograft tumors. (*p < 0.05 vs. vehicle control; n.s., not significant; n = 5). b Hematoxylin and eosin and immunohistochemical (involucrin) staining in serial sections. Keratin pearl formation, characterized by involucrin protein expression, was found in TE-11R-derived xenograft tumors treated with cetuximab but not the vehicle control. On the other hand, no expression was observed in TE-8-derived xenograft tumors in the presence or absence of cetuximab treatment