A recent study has demonstrated that inflammatory molecules such as PGE2 (163) interleukin-1β (IL-1β) (164) and IL-6 (165) produced by tumor cells induce the stem cells present in the bone marrow of tumor-bearing mice to differentiate into Gr-1+CD11b+ MDSCs and to accumulate in the tumor tissue. This evidence concerns the gene IL1B and neoplasm.