APELA and glioblastoma: Because APELA was overexpressed in BTICs, APELA expression was then determined by qPCR in RNA isolated from formalin-fixed paraffin-embedded (FFPE) biopsy specimens obtained from the University of Tennessee Health Science Center (UTHSC) tissue services core from primary low-grade glioma (LGG) (World Health Organization classification I and II), GBM (World Health Organization classification IV), and histologically benign brain samples.