BDNF and cancer: We identified five pathway clusters with highly interconnected common functional pathways (Figure 4): (1) neurotransmitter systems, such as “glutamatergic synapses” and “GABAergic synapses;” (2) brain function, including “long-term potentiation” and “oxytocin signaling;” (3) intracellular signaling cascades, such as “Ras signaling,” “neurotrophin signaling,” and “ErB signaling;” (4) cancer related, such as “prostate cancer,” “pancreatic cancer,” chronic myeloid leukemia;” and (5) stem cell renewal, including “hippo signaling,” TGF-beta signaling,” and “Wnt signaling.”