BLOC1S3 and neoplasm: In zebrafish, MPNSTs are a very rare spontaneous tumor type, but various genetic mutations can predispose fish to develop them including heterozygosity for nf2a (albeit at low penetrance), heterozygosity for any one of various ribosomal protein (rp) genes and homozygosity for an inactivating tp53 mutation, tp53M214K[27], [28], [35].