IDO1 and neoplasm: Based on the gene expression profile of each subpopulation, we classified the tumor cells into several categories, including brain acid-soluble protein 1 (BASP1)_fib, dual specific phosphatase 1 (DUSP1)_fib, indoleamine 2,3-dioxygenase 1 (IDO1)_fib, KIT low DOG+ SMA+_fib, PDGFRA_fib, and KIT-_fib, which were observed in all samples (Fig. 3a, b; Supplementary Fig. 4b).