SELL and neoplasm: L-selectin loss was also detected in circulating T and B cells in MTAG mice with a high cumulative mammary tumor burden (~9000 mm3) and moderate MDSC expansion (14% of CD45+ peripheral blood cells), but not in MTAG mice with low MDSC (7% of CD45+ cells) and tumor burdens (~2500 mm3) (Figure 3—figure supplement 3).