Radiosensitivity and expression of nucleotide excision repair genes in peripheral blood mononuclear cells of myelodysplastic syndrome patients

Abstract

Myelodysplastic syndrome (MDS) is the only other radiogenic blood disease apart from leukemia. Clinically, MDS involves dysplastic hematopoisis and an increased risk of leukemic transformation. We compared the micronucleus (MN) frequency in the peripheral T lymphocytes of atomic bomb survivors with MDS and normal individuals. The spontaneous and X-ray-induced MN frequencies were significantly higher in MDS patients than in normal individuals. To explain the cause of unusual radiosensitivity, we measured the expression levels of nucleotide excision repair (NER) genes in peripheral blood mononuclear cells using an RT-PCR method. The reduction of NER genes was expressed in only 1 of the 10 patients with mild symptoms, but in 4 of the 11 patients with severe symptoms. Our data suggest that chromosomal instability and DNA repair defects may be involved in the pathophysiology of disease progression.