CTNNB1 p.Ser33Phe is a commonly reported missense mutation located within exon 3 which encodes the phosphorylation domain of CTNNB1.[10] This alteration is known to drive nuclear localizations and disrupt phosphorylations.[11] CTNNB1 mutations have not been observed in any of malignant peripheral nerve sheath tumor samples sequenced in COSMIC (COSMIC, November 2015). Here, CTNNB1 is linked to malignant peripheral nerve sheath tumor.