Indian Journal of Science and Technology

Abstract

Importance of subtelomeric chromosome rearrangements associated with idiopathic mental retardation and with methylation of gene expression in neoplastic cells has been shown. In order to observe incidence of deletions or translocations involving subtelomere region in leukemias and lymphomas, 41 patients were observed precisely by chromosome metaphase fluorescent in situ hybridization (FISH) using subtelomere probes and so on, specially focus on the end of long arm of chromosome 11 or short arm of chromosome 17. The abnormalities of subtelomere region on chromosome 11 were frequently observed in 7 of 17 patients (41.6%) with 11q22-q25 abnormalities, which were 3 of 9 patients with add(11)(q23-q25) and 3 of 7 patients with del(11)(q22-25), and 16 of 24 patients (66.0%) with 17p13 abnormalities, which were 2 of 6 with translocation between 17 and other chromosome, 6 of 10 with add(17)(p13) and all of 8 with del(17)(p13). Lymphoid disease had slightly higher abnormalities of subtelomere region than myeloid disease in patients with 11q22-25 or 17p13 abnormalities. Chemo- or radiotherapy treated patients had also subtelomeric chromosomal rearrangements. These results indicate that leukemia and lymphomas have many abnormalities at subtelomere region and possible association of chromosome instability, relating to pathogenesis of these diseases especially after therapy. Furthermore, FISH and chromosome analyses were performed on long-term cultured HL-60 leukemic cell line after irradiation using three different sources, and the results confirmed the higher induction of chromosome instability involving subtelomere region after α-rays irradiation. 
Keywords: Chromosome instability, subtelomere, telomere, radiation, α-rays, γ-rays, β-rays, leukemia cell line, FISH analysis