Gastrointestinal stromal tumors (s) represent about 80% of the mesenchymal neoplasms of the gastrointestinal tract. Most s contain oncogenic (85%) or (5%) receptors. The kinase inhibitor imatinib mesylate is the preferential treatment for these tumors; however, the development of drug resistance has highlighted the need for novel therapeutic strategies. Recently, we reported that the adaptor molecule 3 Binding Protein 2 (32) regulates expression and signaling in human mast cells. Our current study shows that 32 is expressed in primary tumors and cell lines from patients and that 32 silencing leads to a downregulation of oncogenic and expression and an increase in apoptosis in imatinib-sensitive and imatinib-resistant cells. The microphthalmia-associated transcription factor (), involved in expression in mast cells and melanocytes, is expressed in s. Interestingly, is reduced after 32 silencing. Importantly, reconstitution of both 32 and restores cell viability. Furthermore, 32 silencing significantly reduces cell migration and tumor growth of imatinib-sensitive and imatinib-resistant cells in vivo. Altogether, 32 regulates and expression and cell viability, indicating a role as a potential target in imatinib-sensitive and imatinib-resistant s.