Given that changes in the subcellular distribution of CLDN1 are shown to be an independent marker of aggressiveness and poor outcome in a broad spectrum of human malignancies (e.g., colon and triple-negative breast cancer, urothelial carcinoma), we initially compared the subcellular distribution of CLDN1 between IM-sensitive and -resistant GIST. Here, CLDN1 is linked to gastrointestinal stromal tumor.