ATRX and glioma: To identify the biologic relevance of ATRX loss in NF1-associated gliomagenesis, we studied four previously characterized Nf1+/−Trp53+/− murine glioma lines (130G#3, 158D#8, 1491-9, and 1861-10) representing all of the histologic diffuse glioma grades, 2–4 [21].