Abstract
Our previous studies about the effects of continuous low dose rate gamma-irradiation on lifespan and carcinogenesis showed a plausible correlation between the life-shortening and an early occurrence of some neoplasms in mice irradiated with 20 mGy/day; however, the molecular mechanism underlying the early occurrence after irradiation remains to be elucidated. In the present study, we analyzed chromosomal aberrations in malignant lymphomas, which were the most frequently observed, lethal neoplasm in both the non-irradiated control and the irradiated groups, by array-based comparative genomic hybridization (array-CGH) method. We constructed a mouse BAC microarray that contained 672 DNA fragments covering the following important genetic loci: oncogenes, tumor suppressor genes and candidate disease genes identified near the common retrovirus integration sites listed in Retroviral Tagged Cancer Gene Database. The present analysis in a total of 21 lymphomas showed that deletion in a part of chromosomes 19 was observed in about 40% and 18% in non-irradiated control and irradiated groups, respectively. In addition, amplification in a distal part of X chromosome and trisomy 15 were associated preferentially with non-irradiated control and irradiated groups. This work was carried out with financial support from Aomori Prefecture, Japan.
