The goal of this study was to illustrate proper antibody-epitope validation and implement automated image analysis capable of removing confounding background fluorescence in FFPE neuropathology tissue interpretation to test the extent to which a candidate biomarker, Polypyrimidine tract binding protein 1 (PTBP1), could distinguish reactive gliosis versus recurrent glioblastoma. This evidence concerns the gene PTBP1 and glioblastoma.