title: Tumorigenicity Evaluation of Umbilical Cord Blood-derived Mesenchymal Stem Cells.
abstract: Mesenchymal stem cells (MSCs) have been identified in multiple types of tissue and exhibit characteristic self-renewal and multi-lineage differentiation abilities. However, the possibility of oncogenic transformation after transplantation is concerning. In this study, we investigated the tumorigenic potential of umbilical cord blood-derived MSCs (hUCB-MSCs) relative to MRC-5 and HeLa cells (negative and positive controls, respectively) both in vitro and in vivo. To evaluate tumorigenicity in vitro, anchorage-independent growth was assessed using the soft agar colony formation assay. hUCB-MSCs and MRC-5 cells formed few colonies, while HeLa cells formed a greater number of larger colonies, indicating that hUCB-MSCs and MRC-5 cells do not have anchorage-independent proliferation potential. To detect tumorigenicity in vivo, hUCB-MSCs were implanted as a single subcutaneous injection into BALB/c-nu mice. No tumor formation was observed in mice transplanted with hUCB-MSCs or MRC-5 cells based on macroand microscopic examinations; however, all mice transplanted with HeLa cells developed tumors that stained positive for a human gene according to immunohistochemical analysis. In conclusion, hUCB-MSCs do not exhibit tumorigenic potential based on in vitro and in vivo assays under our experimental conditions, providing further evidence of their safety for clinical applications.
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Woojin
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Ok-Sun
authors.initials: OS
authors.lastname: Kim
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Sunyeong
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Su-Yeon
authors.initials: SY
authors.lastname: Han
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Jeong
authors.affiliation: Research Institute, Genexine Co., Seongnam, Korea.
authors.forename: Hyun-Shin
authors.initials: HS
authors.lastname: Park
authors.affiliation: Research Institute, Genexine Co., Seongnam, Korea.
authors.forename: Hea-Won
authors.initials: HW
authors.lastname: Kim
authors.affiliation: Department of Toxicological Evaluation and Research, Korea Institute of Toxicology, Daejeon, Korea.
authors.forename: Kyoung-Sik
authors.initials: KS
authors.lastname: Moon
keywords: Immunohistochemistry; Mesenchymal stem cells; Soft agar assay; Tumorigenicity