Microarray CGH analyses of chromosomal 20q deletions in patients with hematopoietic malignancies

The chromosomal abnormality del(20q) is mostly found in various myeloid disorders, including myelodysplastic syndromes, myeloproliferative neoplasms, and acute myeloid leukemia. Here, microarray comparative genomic hybridization (aCGH) analyses of 14 patients cytogenetically confirmed to carry the del(20q) aberration in their bone marrow demonstrated that all deletions were interstitial and both the proximal and distal breakpoints varied among individuals. The centromeric breakpoints were located in the 20q11.21-12 region, and the telomeric breakpoints, in the 20q13.13-13.33 region. The extent of the deletion ranged from 11.2 to 27.3 Mb, and the commonly deleted region (CDR) was estimated to be 7.2 Mb in size. Two commonly retained regions were present, the proximal region adjacent to the centromere (20q11.1-11.21) and a subtelomeric one (20q13.33). The CDR of our study was more distal than reported previously. Furthermore, in three patients fluorescence in situ hybridization (FISH) demonstrated that del(20q) cells were detected at a higher frequency in the karyotype analyses than by interphase FISH and aCGH analyses. As the size and breakpoints of del(20q) have been reported to vary among patients, the presence of one or more tumor suppressor genes in the CDR has been suggested. Our study will contribute to the identification of candidate tumor suppressor genes on 20q.