DFMO inhibits ESCC progression in a PDX model. A PDX model of mice implanted with human ESCC (EG20) were divided into three groups and treated with vehicle or 2% (v/v) or 4% (v/v) DFMO in drinking water for a total of 33 days. a From the 1st day of treatment, body weight and tumor volume were measured every 3 days. DFMO did not significantly reduce mouse body weight compared with the vehicle group. b From the 9th day of treatment, the average tumor volume of both DFMO-treated groups appeared to be significantly less than the vehicle-treated group. c Compared with vehicle, DFMO treatment significantly decreased the weight of the PDX tumors. d IHC analysis was performed to determine the expression levels of PCNA, Ki-67, cleaved caspase 3, and Bcl-2 in ESCC PDX tumors treated with vehicle or DFMO. Representative photographs for each antibody and each group are shown. The integrated optical density (IOD) was evaluated using the Image-Pro Plus software (v.6.0) program. All data are shown as mean values ± S.D