NGFR and glioma: The role of processing of p75NTR was not limited to a single glioma cell line and was a general mechanism observed in glioma cells established from genetically distinct individuals (U87p75, U251p75, U343p75, and U118p75).We found that in all p75NTR-positive glioma cell lines, full-length p75NTR was cleaved to generate two fragments of 19 and 24 kDa: ICD and CTF, respectively (Figure 1C).