Our study revealed 7.7% (4/52) of ALK expression in PDGFRA-mutant GISTs, indicating that molecular tests were required to rule out the possibility of PDGFRA-mutant GISTs when encountering ALK-positive mesenchymal tumors with CD117-negative or weakly positive in immunohistochemical staining. Here, KIT is linked to mesenchymal cell neoplasm.