IFNB1 and neoplasm: Many studies have shown that MSCs engineered to express anti-tumour cytokines, such as interleukin-2 (IL-2) [54], interferon-beta (IFN-β) [55], TRAIL [45,46,48], and IL-15 [56], are able to deliver these ligands directly to the tumour site and to efficiently induce tumour regression.