Here, we synthesized two different IVT mRNAs that encode a reporter protein (DsRed) and a growth factor (GM-CSF) and demonstrated that their transfection into MSCs did not affect cells’ hallmarks: MSCs modified with IVT mRNA maintain their phenotypic properties, including the absence of immunogenicity markers and the ability to migrate and engraft into tumours, which are beneficial properties for therapeutic purposes in cancer treatment. The gene discussed is CSF2; the disease is cancer.