CSF2 and cancer: 17, 18 The levels of GM-CSF were found to increase in cancer patients, which induced accumulation of MDSCs.19, 20, 21 We therefore treated bone marrow cells from Balb/c mice with 20 ng/ml of GM-CSF for 5 days and found that more than 70% of Balb/c bone marrow CD11b+CD11c− cells were Ly6Ghi gMDSCs and <10% of them were Ly6Chi mMDSCs (Figure 3b).