Systematic collection of tissue specimens and molecular pathological analysis of newly diagnosed solid cancers among atomic bomb survivors

To elucidate precise mechanism of radiation-induced cancers, it is important to analyze the genetic and epigenetic alterations in cancer cases among atomic bomb (A-bomb) survivors. Stored tissue samples are damaged in a certain extent, and fresh tissue samples are suitable for molecular analyses. We have established a network system comprising major hospitals in Hiroshima area, Hiroshima University and Radiation Effects Research Foundation (RERF) to conduct systematic collection and storage of fresh tissue samples of newly diagnosed solid cancers among A-bomb survivors. The project is carried out as “The Ministry of Health, Labor and Welfare of Japan Group Study on A-bomb Diseases.” The subjects of this study are RERF Life Span Study (LSS) cohort members (> 0 dose) who have been diagnosed with cancer of the stomach, colorectum, esophagus, breast, or lung, and have undergone surgery. As controls, LSS cohort members (= 0 dose) and non-LSS members matched by sex, age, and medical institution are selected. Using the tissue samples thus collected, we are searching for genetic and epigenetic events involved in the development of solid cancers. We have developed custom-made 3-dimension oligo-DNA microarray with a total of 207 genes including those related to DNA damage response and repair. We identified 10 genes whose expression levels in the tumors were significantly different between A-bomb survivors (LSS: > 0 dose) and control subjects. They might be candidate genes which participate in radiation-induced carcinogenesis and possible genetic markers for radiation-induced solid cancer.