title: Low dose effects of ionizing radiation on normal tissue stem cells.
abstract: In recent years, there has been growing evidence for the involvement of stem cells in cancer initiation. As a result of their long life span, stem cells may have an increased propensity to accumulate genetic damage relative to differentiated cells. Therefore, stem cells of normal tissues may be important targets for radiation-induced carcinogenesis. Knowledge of the effects of ionizing radiation (IR) on normal stem cells and on the processes involved in carcinogenesis is very limited. The influence of high doses of IR (>5Gy) on proliferation, cell cycle and induction of senescence has been demonstrated in stem cells. There have been limited studies of the effects of moderate (0.5-5Gy) and low doses (<0.5Gy) of IR on stem cells however, the effect of low dose IR (LD-IR) on normal stem cells as possible targets for radiation-induced carcinogenesis has not been studied in any depth. There may also be important parallels between stem cell responses and those of cancer stem cells, which may highlight potential key common mechanisms of their response and radiosensitivity. This review will provide an overview of the current knowledge of radiation-induced effects on normal stem cells, with particular focus on low and moderate doses of IR.
authors.affiliation: Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany. Electronic address: katrin.manda@uni-rostock.de.
authors.forename: Katrin
authors.initials: K
authors.lastname: Manda
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom. Electronic address: j.kavanagh@qub.ac.uk.
authors.forename: Joy N
authors.initials: JN
authors.lastname: Kavanagh
authors.affiliation: Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany. Electronic address: dajana.buttler@uni-rostock.de.
authors.forename: Dajana
authors.initials: D
authors.lastname: Buttler
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom. Electronic address: k.prise@qub.ac.uk.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Prise
authors.affiliation: Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany. Electronic address: guido.hildebrandt@uni-rostock.de.
authors.forename: Guido
authors.initials: G
authors.lastname: Hildebrandt
keywords: Carcinogenesis; Irradiation; Low dose; Normal stem cells