TGFB1 and neoplasm: Immune dysregulation in the bone marrow is driven in part by soluble components such as transforming growth factor (TGF)-β, interleukin (IL)-10, IL-6, and prostaglandin E2, which are produced by the malignant plasma cell and by other suppressive cell populations in the tumor microenvironment, including regulatory T cells, myeloid derived suppressor cells (MDSCs), and bone marrow stromal cells (6).