This study was performed to demonstrate the transportation of an engineered MSC-produced intracellular anticancer gene product between mesenchymal stem cell (MSC) and cancer cells.  MSC-mediated anticancer strategy has held great promise owing to MSCs’ capacity of tumor-directed migration and the availability of specific anticancer genes.  All anticancer genes that have been used in previous MSC-mediated anticancer studies were limited in functioning via extracellular mechanisms, mainly because of the restriction by cell membrane to macromolecules including proteins.  In order to apply the majority of potent anticancer genes to the MSC-mediated anticancer system, a specifically designed expression vector which bears an intracellular anticancer gene, PTEN, is utilized to demonstrate the feasibility of the system in cancer therapies.  A transacting activator of transcription (TAT) was introduced into an expression vector followed by a segment for PTEN-RFP fusion protein.  A direct demonstration of PTEN-RFP transportation between MSC and cancer cells was obtained from direct co-cultures.  A marked cancer cell death was observed in indirect co-cultures with conditioned media from PTEN-transfected MSCs.  The demonstration of PTEN-engineered MSC-produced PTEN transportation indicates the feasibility of applying intracellular anticancer gene expression system in MSC-mediated strategies for cancer therapy.