Nonrandom rearrangements of 6p in malignant hematological disorders

It is very uncommon to observe nontranslocation abnormalities (NTAs) involv ing the short arm of chromosome 6 (6p) in malignant hematological disorders (MHDs). Br using conventional cytogenetics and fluorescence in situ hybrid ization (FISH) with chromosome-microdissection probes specific for 6p21 and 6p25, we observed five patients with myeloid malignancies and two patients with lymphoid malignancies to hare 6p NTAs. On the basis of our data and t hose in the literature, it is possible to dir-ide 6p NTAs into the followin g three groups in MHD: The first group presents with 6p NTAs as a sole or p rimary change in myeloid malignancies. There are only two cases reported in this group, including one case with del(6)(p23) and the present case with ins(6)(q23p23p25) identified by FISH only. The second group presents with 6 p deletions as a sole or primary change in lymphoid malignancies. Three cas es have been reported in this group, including one case with del(6)(p21p23) , one with del(6)(p21), and the present case 2 with del(6)(p21). The third group has lip deletions in addition to other known primary changes, present in both myeloid and lymphoid disorders, with 36 cases reported, including five cases from our series. Deletions involving 6p21, 6p22, or 6p23 have be en observed in both myeloid and lymphoid disorders. The present data provid e cogent information for further molecular characterization of 6p anomalies in MHD. (C) 2000 Elsevier Science Inc. All rights reserved.