Molecular features of pleomorphic xanthoastrocytoma.

Pleomorphic xanthoastrocytoma (PXA) is a rare central nervous system tumor occurring mostly in children and young adults. Next-generation sequencing of 295 cancer-related genes was used to investigate the molecular profiles of 13 cases of PXA. We found that BRAF V600E (5/13; 38%), FANCA/D2/I/M (5/13; 38%), PRKDC (4/13; 31%), NF1 (3/13; 23%), and NOTCH2/3/4 (3/13; 23%) alterations were the most frequent somatic gene mutations. However, neither PTEN nor EGFR mutation, which is frequently present in glioblastoma, was detected. The KRAS mutation in PXA is reported for the first time in these tumors. Microsatellite stability was present in all cases. Because mutations of FANCA and BRAF and copy number variations of CDKN2A/B are more frequent in PXA than in glioblastoma, they might be used to distinguish the 2 tumors. The MAPK pathway is involved in the pathogenesis of PXA and may be an effective target for treatment.