CDKN2B-AS1 and plexiform neurofibroma: Interestingly, the polymorphism rs2151280 located in the lncRNA ANRIL (CDKN2B antisense RNA 1) [12] was associated with the number of plexiform neurofibromas (PNFs) in NF1 patients, and 9p21.3 deletions, including the CDKN2A/B–ANRIL locus, are detected in PNFs [13].