DFMO, an FDA-approved drug for treatment of Trypanosomiasis, is an enzyme-activated irreversible inhibitor of ODC and acts to deplete polyamine pools. The antitumor effects of DFMO on various solid tumors, including colon cancer,50 skin cancer,14 pancreatic cancer,51 and breast cancer, has been reported in both preclinical and clinical studies.52 However, DFMO is generally cytostatic in mammalian cells, causing a reduction in the rate of proliferation in the absence of cell death.53 Based on our studies using shODC, DFMO’s effect on ESCC was examined. As expected, DFMO treatment not only suppressed proliferation, but also induced apoptosis of ESCC cells by inhibiting ODC activity (Fig. 5).