Effect of CHST15 siRNA on tumor histology in a xenograft model.

<p>(A, B) Tumors in nude mice at day 19 were stained with HE (original magnification ×100). Representative pictures were shown. Widespread necrosis lesions were prominent in the CHST15 siRNA treated mice (A) compared to the control siRNA treated mice (B). (C, D, E, F, G) Immunohistochemical staining of CHST15 (brown, original magnifications ×100 for C, D, x400 for E, F, G) in xenografts at day 19. Representative pictures were shown. Although almost all tumor cells in xenograft were positive for CHST15 in control siRNA treated mice (D), strong positive signal was observed in the invasive front rather than the center of tumor. CHST15-highly positive tumor cells exhibited mesenchymal-like morphology (E) while CHST15-low positive cells exhibited cord-like morphology (F), In contrast, small number of remnant tumor cells was weakly positive for CHST15 in CHST15 siRNA treated mice (C).