APC and neoplasm: LAT1 staining confirmed that the entire tumor was LAT1-positive in LAT1fl/fl; ApcMin/+ mice and LAT1-negative in LAT1fl/fl; vil-cre; ApcMin/+ mice, which might suggest that LAT1-positive cells in the crypt base include stem cells because Apc Min/+ tumors are shown to develop from stem cells [22] (Fig. S5).