Cluster analysis further underscored the immunophenotypic heterogeneity of small bowel mesenchymal tumors, delineating three main profiles: classical GIST (CD117+/DOG1+/CD34+), a partial GIST/leiomyomatous pattern (CD117+/SMA+/CD34+), and a CD117–/DOG1– non-GIST group encompassing adenocarcinomas, NETs, and lymphomas. This evidence concerns the gene SMN1 and gastrointestinal stromal tumor.