BDNF and astrocytoma (excluding glioblastoma): The absence of p75NTR neurotrophin receptor in astrocytomas included in this study erases the possibility of apoptosis mediated by binding of pro-neurotrophins (pro-NGF and/or pro-BDNF) to p75NTR, even in the presence of survival-promoting Trk receptors [5-8], in these tumors.