Treatment with 5-FU effectively reduced both numbers and sizes of tumor organoids derived from intestinal tumors of ApcMin/+/Lgr5EGFP mice and significantly suppressed their growth (Fig. 1a, b); however, in the residual tumor organoids, the intensity of the CSC marker Lgr5 was significantly increased as monitored by GFP signal (Fig. 1c). Here, LGR5 is linked to intestinal neoplasm.