EPOR and neoplasm: Doxycycline-induced knockdown of EPOR significantly increased tumor tripling time from 12.0±1.6 (shSCR−dox), 11.2±1.5 (shSCR+dox), 12.0±1.0 (shEPOR−dox) days to 23.6±2.6 (Figure 5B).