A new nonrandom unbalanced t(17;20) in myeloid malignancies.

Deletions of chromosomes 17 and 20 are well-described abnormalities in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) but translocations involving these two chromosomes are uncommon. We present five male patients, one with MDS and four with AML, in whom a new, nonrandom unbalanced dicentric t(17;20), resulting in deletions of 17p and 20q, was identified. Conventional cytogenetics showed additional karyotypic abnormalities in most of the patients, including deletions of 5q, deletions or monosomy of chromosome 7, and deletions of 18q. Fluorescence in situ hybridization showed a deletion of the tumor suppressor gene TP53 on 17p. Of the four cases with follow-up data available, only two had received combination chemotherapy. Overall survival in these two cases was 6 and 7 weeks, respectively. Two other patients who had no active therapy administered died 6 weeks and 9 months after diagnosis, respectively. These five cases highlight a rare but recurrent abnormality in MDS and AML, potentially involving genes on 17p and 20q of importance in myeloid leukemogenesis.