Establishing a new evaluation system to characterize radiation carcinogenesis by stem cell dynamics (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; National Institutes for Quantum Science and Technology*

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Establishing a new evaluation system to characterize radiation carcinogenesis by stem cell dynamics" conducted in FY2020. In this study, the long-term clonal expansion of mammary stem cells after high- to low-dose radiation exposure was investigated using stem-cell lineage tracing technology that can permanently label stem cells and their progenies. The purpose of this study is to characterize radiation-induced breast cancer based on the dynamics of radiation-exposed stem cells by capturing proliferation and analyzing it using a mathematical model.