In addition, a variety of spindle cell neoplasms are nuclear-positive for beta-catenin: low-grade myofibroblastic sarcoma (LGMS), gastrointestinal stromal tumor (GIST), solitary fibrous tumor (SFT), and desmoplastic fibroblastoma (DF). This evidence concerns the gene CTNNB1 and gastrointestinal stromal tumor.