Trisomy 4 in acute nonlymphocytic leukemia. Report of two cases and review of the literature.

Two patients with M2 subtype of acute nonlymphocytic leukemia (ANLL) and trisomy 4 as a primary karyotype change are described. The abnormality was observed in 100% of bone marrow (BM) metaphases in both cases. It appeared alone in one case and was associated with trisomy 13 in 94% of metaphases in the other. These are the second and third cases of ANLL with trisomy 4 documented in Italy. Neither patient appears to have incurred any environmental or therapeutic insult.

In vitro bone marrow cell culture and cytogenetic analysis in a case of myelodysplasia.

A case of refractory anemia with sideroblastosis and a number of bone-marrow blasts slightly over the limit which separates the I/II and III FAB-subtypes of myelodysplastic syndromes is described. The leukemic-like type of in vitro growth and the multiple karyotypic changes observed in the bone-marrow cells at presentation were both indicators of the malignant nature of the disorder and underlined the importance of these studies in assessing diagnosis and prognosis in patients with preleukemic disorders. The role that the chromosome aberrations, del(11)(q14) and del(18)(q21), both found in 100% of the bone-marrow metaphases examined, may play in the pathogenesis of the disease is also discussed.

Partial trisomy 1q in idiopathic myelofibrosis.

Three cases of idiopathic myelofibrosis with partial trisomy of the long arm of chromosome 1 are described. Partial trisomy 1q was the only karyotypic change detectable in unstimulated peripheral blood cell cultures of one and bone-marrow cultures of two patients at diagnosis. The extra segment from chromosome 1 was located on different karyotype sites, i.e. 1qter, 1p34 and 6p22-23; 1q21-32 was the shortest overlapping region and the only trisomic segment in one of the three patients. These findings suggest that partial trisomy 1q is a primary chromosome aberration in myelofibrosis relevant in the pathogenesis of this hematologic disorder.

Evolution of multiple cytogenetic clones and leukemic transformation in a case of myelodysplastic syndrome.

The cytogenetic follow-up of a case of refractory anemia with excess of blasts (RAEB) that rapidly evolved to acute myeloblastic leukemia (M1-FAB type) is described. Bone marrow analysis at presentation revealed two chromosomally abnormal clones that shared an interstitial deletion of the long arm of chromosome 5 (5q-) and a terminal deletion of the short arm of chromosome 12 (12p-), but that differed from one another in the localization of a very similar segment of chromosome 17 (i.e. 17q11-12qter) on two clearly distinct karyotypic sites: 2q37 and 17q25. Fourteen percent of the metaphases examined bore the 2q+ marker and 38% the 17q+ marker; the remaining cells had a normal karyotype. A second study carried out 4 months later, at onset of the acute phase, revealed that the clone with normal karyotype had almost completely disappeared and that there had been an inversion in the ratio of the two abnormal cell populations. In the final study, made 1 month before death, the cells with t(2;17) had totally effaced the other clone. These findings seem to indicate that, among the karyotypic changes that occurred in an original clone with 5q- and 12p-, only the t(2;17) could have played a crucial role in the final leukemic transformation.

5q- syndrome terminating in acute myeloid leukemia. Karyotype evolution and immunologic characterization of blast cells.

We report a case of 5q- syndrome that progressed to acute nonlymphocytic leukemia after 9 years of clinically and morphologically stable disease. The transition from the chronic to the leukemic phase was characterized by the appearance of an additional cytogenetic anomaly [inv(2)] in the cell carrying the 5q-, together with the expansion of a clone showing an apparently normal karyotype.

ins(6;11) in a case of peripheral T-cell lymphoma.

Cytogenetic investigation of lymph node-derived cells taken from a peripheral T-cell lymphoma patient revealed an insertion of the segment 11q21q25 into the band p22 of chromosome #6 as the only anomaly. The probable role of the three rearranged chromosomal regions on the development of this neoplasia is discussed.

Variant Philadelphia translocation in an immunologically and clinically typical case of chronic myeloid leukaemia.

Cytogenetic analysis of bone marrow from a chronic myeloid leukemia patient in chronic phase revealed a classical Philadelphia chromosome from a complex translocation t(2;9;22). The break points on 9 and 22 were, apparently, the same as for the standard translocation (9;22). However, whereas the terminal band of 9 (9q34) was translocated in the usual site, that is on 22q-, the tract deleted from 22 was present on band p13 of chromosome 2. The finding of this rare 22 translocation in classical CML would seem to support the hypothesis that the crucial event in the pathogenesis of CML is the translocation of band 9q34, that contains the c-abl oncogene, onto the Ph' chromosome, rather than the translocation of the tract deleted from 22 to some other chromosome site.