19p deletion in recurring leiomyosarcoma lesions from the same patient

Ten leiomyosarcomas (LMS) affecting the same patient over a period of 3 yea rs were cytogenetically studied to detect nonrandom chromosomal changes wit h a pathogenetic significance. All tumors, likely metastases of a previous LMS presentation, were classified as small, including eight that developed before chemotherapy; the diagnoses were based on standard immunohistochemis try methods for smooth muscle tumors. Scoring of 613 metaphases revealed mo nosomy of chromosome 22 in six LMS, monosomy of chromosome 19 in three, and deletion of chromosome 19p in all ten. Interphase fluorescence in situ hyb ridization (FISH) of the 22-alphoid-specific probe allowed loss of the targ et chromosome to be detected in four tumors at higher frequencies than thos e detected by cytogenetics. Double-color FISH of the 19p- and 19q-specific YAC performed on one tumor made it possible to distinguish the monosomic an d 19p deleted cells, the relative frequencies of which were found to be 10% and 20%, respectively. The deletion breakpoint could be mapped at 19p13 be tween YAC 957d12 and YAC 947g4. The recurrence of the 19p deletion in a sub set of tumor cells from all of the analyzed LIMS suggests that this structu ral aberration is a significant change in the development of leiomyosarcoma s. (C) 2000 Elsevier Science Inc. All rights reserved.