Abstract
1) Susceptibility of ionizing radiation from atomic bomb (A-bomb): Differences on sensitivity to A-bomb radiation are suggested among the survivors. We demonstrated that a rat strain possessing sympathetic hyperfunction showed a lower survival rate, a higher weight loss, and a severer intestinal injury than control animals after a whole body irradiation. Disturbance of the autonomic nervous system, particularly sympathetic hyperfunction might be associated with increased sensitivity to acute radiation injury in human. 2) Multiple primary cancers (MPC) in A-bomb survivors: An increased risk of cancer has continued for decades. We have recently described a higher incidence rate of MPC in the survivors, particularly for those who were exposed at a younger age and at a closer distance from the hypocenter. The occurrence of MPC is considered to be a reflection of systematic exposure to environmental carcinogens or of a predisposition to cancer. These results provide evidence for the involvement of A-bomb radiation in MPC among the survivors. A higher risk of cancer, as a late effect of A-bomb radiation, still persists in survivors. 3) Biological resources from A-bomb survivors: The epidemiologic and molecular analyses regarding carcinogenesis in the survivors require clinical data of individuals and biological materials with pathologic data of tumors. Biological materials for solid tumors from Nagasaki survivors have been mainly kept as formalin-fixed paraffin-embedded tissues at the hospitals in the Nagasaki city. Recently, because of the technical advance, several important molecular data about radiation-related tumorigenesis with archival materials from the survivors have increasingly reported. We are definitely required to collect and reserve these biological resources from the survivors for future studies.
