Daskalakis and colleagues have analyzed the transcriptomic profile within the blood and key-stress sensitive brain areas (i.e. amygdala and hippocampus) in PTSD-susceptible and resilient rats, and they found that 22 genes encoding for growth factors were differentially expressed, and 5 of them (angiotensinogen, epidermal growth factor, fibroblast growth factor 2, nerve growth factor, TGF-β1) were convergent across tissue Daskalakis et al., 2016. This evidence concerns the gene NGF and post-traumatic stress disorder.