EPO and stroke disorder: Transplantation of stem cells whose genes have been modified using viruses to express neurotrophic and growth factors, such as BDNF, VEGF, NGF, GDNF, Noggin, placental growth factor (PIGF), hepatocyte growth factor (HGF), erythropoietin (EPO), angiopoietin-1 (ANG-1), and IL-10 has been proven to be more effective in promoting neuronal tissue regeneration compared to the unmodified stem cells in experimental stroke animal models (Wang et al., 2004; Ding et al., 2011; Chen et al., 2013; Nakajima et al., 2017; Wang et al., 2018; Moxon et al., 2019).