Fig. 1. Gimatecan inhibits tumor growth in patient-derived xenograft (PDX) models of esophageal squamous cell carcinoma (ESCC).

a–e In vivo antitumor activity of gimatecan in ESCC PDX models. Tumors were subcutaneously engrafted and grown in NOD/SCID mice until they were 150–200 mm³ in size. Then the mice were treated with saline containing 10% DMSO or gimatecan (0.25 mg/kg, d1–d5/week, oral gavage) for 3 weeks, and tumors were measured twice a week. Tumor volume is expressed as the mean ± SD of at least five mice in each group. Antitumor activity was analyzed using unpaired two-tailed t-tests, and is depicted by tumor growth inhibition. **P < 0.01, ***P < 0.001, f Images of tumors dissected out from killed mice. A representative image of PDX 2 at the end of treatment is shown