Suppression of REV7 enhances cisplatin (CDDP) sensitivity in vivo. (a) Growth of inoculated tumors in nude mice with and without systemic CDDP treatment. REV7-knockdown (shREV7) or control (shCont) ovarian clear cell carcinoma TOV-21G cells (1 × 107) were used in this analysis. The means ± SDs of tumor volume are shown. *P < 0.05; **P < 0.01. (b) Macroscopic images of transplanted tumors excised at day 32. (c) Reduction of tumor volume by CDDP treatment. Tumor volumes of the CDDP-treated group relative to the mean tumor volume of the PBS-treated group were calculated, and the means ± SDs of relative tumor volumes are shown. *P < 0.05. (d) Immunohistochemical analysis of excised tumors for REV7, cleaved caspase-3, and phospho-H2AX. Excised tumor tissues at day 32 were immunohistochemically stained with anti-REV7 (upper panels), anti-cleaved caspase-3 (middle panels), and anti-phospho-H2AX (lower panels) antibodies. Scale bar = 50 μm. (e, f) Quantitative assessment of cleaved caspase-3-positive cells (e) and phospho-H2AX-positive cells (f) in shREV7 and shCont tumors. Cells were counted under high power fields (HPF). The data obtained from five separate fields are shown as means ± SDs. **P < 0.01.