Previous reports demonstrated a role for NF-kB in the regulation of MICA expression in different types of cells (e.g. T lymphocytes, endothelial cells and MM cells) (37, 38) NF-kB proteins are constitutively active in MM cells but BMSCs produce many soluble factors, including GAS6, which further trigger this signaling pathway in these tumor cells (16, 20, 39, 40). This evidence concerns the gene MICA and neoplasm.