Living in Space
Integral Understanding of life-regulation mechanism from "SPACE"

Estimation of carcinogenic risk after exposure to space radiation by pathological and genomic analyses – Publicly Invited Research 2016－2017

1. A01 Akiyama
2. A01 Ochi
3. A01 Chatani
4. A01 Seiki
5. A01 Nikawa
6. A01 Kawakami
7. A01 Tomita
8. A01 Honda

1. A02 Shinohara
2. A02 Maekawa
3. A02 Ohgami
4. A02 Nishimura
5. A02 Kawano
6. A02 Iwase
7. A02 Furuichi
8. A02 Myung
9. A02 Kitamura

1. A03 Nakamura
2. A03 Harada
3. A03 Ide
4. A03 Shirai
5. A03 Kakinuma

1. B01 Lazarus
2. B01 Miwa
3. B01 Kunieda
4. B01 Shimada
5. B01 Kitaya
6. B01 Sawano

Research Subject	Estimation of carcinogenic risk after exposure to space radiation by pathological and genomic analyses
Research Group Leader	Shizuko Kakinuma Director, Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology Website http://
Research Collaborator(s)	Takamitsu Morioka principal researcher, Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology Yi Shang Researcher, Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology Yoshiko Amasaki Researcher, Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology Kazuhiro Daino Senior Researcher, Department of Radiation Effects Research National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology

Unlike on the earth's surface, in space we are exposed to a different spectrum of radiation including cosmic radiation. Cosmic radiation includes high energy heavy particles such as iron ions, as well as protons and neutrons, with the potential for high biological effectiveness. Although the biological effects of radiation and the relation between dose and carcinogenic risk can be understood from epidemiological data, such as that on atomic bomb survivors, there is insufficient data on carcinogenic risk from the mixed radiation field at low doses / low dose rates relevant to the space environment. Although the fluence of heavy particles in space is low, the dense and complex DNA lesions that can be formed from the passage of such ions as iron or silicon through the cells make the repair of cells more difficult, and may have greater biological effectiveness and thus greater cancer risk than for low LET radiation.

In this study, we will analyze tumor samples obtained from lifespan experiments in B6C3F1 mice after irradiation with iron, silicon or argon ions. First, we will perform pathology analysis of tumors induced after heavy ion exposure from a variety of organs, and then analyze genomic mutations in the tumors. We aim to compare the pathology and genomic data to similar data from previous low LET radiation studies, in order to understand the differences in carcinogenic mechanisms and risk due to high energy heavy ion exposure, such as would be experienced in the space radiation environment.