BDNF and colorectal cancer: Although neurotrophins are best known for their effects on neurons and tumors of the nervous system, they also exert effects on tumors outside the nervous system.32 Neurotrophin signaling has been implicated in leukemogenesis,33 and is a prognostic factor in human pancreatic and colorectal cancer.34, 35 It is plausible that DOK6 mediates neurotrophin/NGF signaling because DOK5, which occupies the same phylogenetic branch of the DOK family, functions as an adaptor in neurotrophin-3/TrkC signaling.36