Pasmant and colleagues identified a recurrent somatic alteration in PNFs, the 9p21.3 deletion (including the CDKN2A/B-ANRIL locus), in 6 out of 22 PNF tumors from 18 NF1 patients, analysed by a genome-wide array of comparative genomic hybridization. Here, CDKN2A is linked to neurofibromatosis type 1.