CSF2 and liver cancer: To examine the effect of HSCs on the differentiation of MDSCs in the tumor environment in vitro, HSCs were added into the BM cell culture at a ratio of 1:40 with or without an equal amount of liver cancer cells (HCCs; Hepa 1-6 cells originated from the mouse hepatoma cell line) in the presence of GM-CSF (8 ng/mL).