Figure 4: Existence and manner of clonal expansion of Lgr5+ cells in developing small intestinal tumors and colon tumors.

(a,c,e) The percentage of the developing tumors that contained Lgr5+ positive cells was calculated by observing EGFP using tumor-bearing Lgr5^{EGFP-IRES-CreERT2/} mice of three models; FAP model (a), two-step carcinogenesis model (c), and sporadic carcinogenesis model (e). To assess the percentage of the tumors containing Lgr5+ cell-derived clone, FAP model, two-step caricinogenesis model, and sporadic carcinogenesis model were set up using Lgr5^{EGFP-IRES-CreERT2/+}; Rosa26^rbw/+ mice, followed by tamoxifen induction and chase to trace the lineage of Lgr5+ cell (a,c,e): Day7 and Day28. This analysis excluded GFP+ clones because we cannot judge whether the origin of the GFP+ clone is the cell that expressed GFP accompanied by Lgr5 or the Lgr5-negative cell, owing to ubiquitous expression of GFP in Rosa^rbw mice. The number of mice and tumors analyzed were shown in Supplementary Table 3. (b,d,f) The number of the cells that comprised each Lgr5+ cell-derived clone was measured, and the average is shown. Cell number per clone at day28 after tamoxifen induction was compared with day7. Error bars indicate standard deviation. **p < 0.01, *p < 0.05. The number of tumors analyzed and the raw data are shown in Supplementary Table 2.