As previously reported, GA-amide was found to bind with TrkA at the juxtamembrane regions, an event that was determined to be necessary for the membrane penetration of GA-amide since the deficiency of TrkA in the area prevented the entry of GA-amide into the cells.18 Based on this, we examined the expression of TrkA in normal brain tissues and glioma tissues from the same mice. This evidence concerns the gene NTRK1 and central nervous system cancer.