The alternative lengthening of telomere phenotype is significantly associated with loss of ATRX expression in high-grade pediatric and adult astrocytomas: a multi-institutional study of 214 astrocytomas.

Loss-of-function of alpha thalassemia/mental retardation syndrome X-linked (ATRX) protein leads to a phenotype called alternative lengthening of telomeres (ALT) in some tumors. High-grade astrocytomas comprise a heterogeneous group of central nervous system tumors. We examined a large cohort of adult (91) and pediatric (n=88) high-grade astrocytomas as well as lower grade forms (n=35) for immunohistochemical loss of ATRX protein expression and the presence of ALT using telomere-specific fluorescence in situ hybridization, with further correlation to other known genetic alterations.