KIAA1549 and pilocytic astrocytoma: In general, somatic duplication of 7q34 is specific for pilocytic astrocytomas and molecular analysis of tumor samples for KIAA1549:BRAF fusions is diagnostic [19] in absence of co-occurring 1p deletions, which points to the differential diagnosis of a morphologically distinct diffuse leptomeningeal glioneuronal tumor [20].