Open questions addressed in this study include (i) the actual frequency of FGFR1 N546 and K656 hotspot mutations in an unselected collection of low-grade brain tumors independent of their histological designation and (ii) the potential screening role of FGFR1 immunohistochemistry to identify FGFR1 alterations in such tumors. This evidence concerns the gene FGFR1 and brain neoplasm.