ID1 and neoplasm: We found that, similar to defects seen in tumour-bearing mice, Id1-overexpressing mice exhibited a decrease in splenic DCs (1.5-fold; Fig. 3a) and an increase in MDSCs (2.7-fold; Fig. 3b) compared with control vector mice, with both granulocytic and monocytic populations being equally affected (Supplementary Fig. 3A,B).