NGFR and neoplasm: The p75 neurotrophin receptor (p75NTR), also known as NGFR/CD271, is a component of the tumor necrosis factor receptor superfamily that commonly binds to neurotrophins, such as neurotrophin-3 and -4/5, nerve growth factor, and brain-derived neurotrophic factor.19 p75NTR mediates cellular events such as cell apoptosis, adhesion, differentiation, and invasion, and may be involved in intracellular signaling.19,20 Besides being a tumor marker, especially in the gastrointestinal tract,21 p75NTR is regarded as a marker of mesenchymal and epithelial stem cells.