NGFR and central nervous system cancer: Frozen tumor tissue was digested in lysis buffer and analyzed by western blots using a p75NTR cytoplasmic-specific antibody that not only detected the full-length p75NTR protein, but also detected p75NTR-positive fragments migrating at 24 and 19 kDa, respectively, in the p75NTR-positive specimens (eight of nine GBMs and two of five Grade III glioma) (Figure 1A).