For example, in rodents, administration of chemotherapy agents used for breast cancer have been associated with reduced hippocampal neurogenesis (Seigers et al., 2008; Janelsins et al., 2010), hippocampus-related cognitive deficits (Foley et al., 2008; Walker et al., 2011), and reduced levels of brain-derived neurotrophic factor (BDNF) in the hippocampus (Mustafa et al., 2008), a molecule known to be a mediator of neurogenesis and critical for memory formation (Figurov et al., 1996; Kang and Schuman, 1996; Pang et al., 2004). This evidence concerns the gene BDNF and Cognitive impairment.