title: MSCs, macrophages, and cancer: a dangerous ménage-à-trois.
abstract: Two studies in this issue of Cell Stem Cell highlight context-dependent roles for MSCs in controlling tumor growth. Lee et al. (2012) show that preactivated MSCs have antitumor effects upon adoptive transfer in vivo, and Ren et al. (2012) show that tumor-resident MSCs can promote tumor growth by influencing macrophages.
authors.affiliation: Humanitas Clinical and Research Center, University of Milan, Via Manzoni 56, 20089 Rozzano, Milano, Italy. alberto.mantovani@humanitasresearch.it
authors.forename: Alberto
authors.initials: A
authors.lastname: Mantovani