IL2 and neoplasm: In cancer therapy approaches, MSCs have been used for tumor delivery of immunostimulatory cytokines and chemokines (interferon [IFN]-α [4], IFN-β [5–8], interleukin [IL]-2 [9], IL-12 [10, 11], and CX3CL1 [12]), suicide genes (thymidine kinase [13] and cytosine deaminase [14]), growth factor antagonists (NK4) [15], and oncolytic viruses [16, 17] after systemic administration, taking advantage of their tumor-homing capacities, or by intratumoral inoculation.