Chromosomal Gain Aberrations Predominate in Murine Myeloid Leukemia Induced by Continuous Exposure to Low-dose γ-radiation

Abstract

How continuous exposure to low doses of radiation affects lifespan and health status is essentially unknown. Leukemia is a type of blood cancer that develops in humans and mice soon after irradiation. We compared chromosomal aberrations between LDR-induced murine myeloid leukemia (ML) and spontaneous ML to clarify the leukemogenic effect of chronic low-dose radiation (LDR). Formalin-fixed, paraffin-embedded spleens from mice with spontaneous ML (n = 11) and ML that developed after 400 days of exposure to 20 mGy/22 h/day of γ-radiation (n = 11) were analyzed using array comparative genomic hybridization (array CGH). We found that gain aberrations predominated among the chromosomal anomalies of LDR-induced ML, whereas loss aberrations were most prevalent in spontaneous ML. The genomic regions with gain aberrations of LDR-induced ML included the Etv6, Ntrk2 and Rasgrf2 genes that are associated with leukemia or self-renewal. Exposure to chronic LDR induces ML via a mechanism that differs from that of spontaneous ML.