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Background and Objective: From 5-8% of Philadelphia (Ph) positive patients with chronic myeloid leukemia (CML) show variant translocations in which at least a third chromosome in addition to 9q34 and 22q11 is involved. The formation mechanisms and clinical significance of variant Ph translocations are still unclear. The BCR/ABL chimeric gene encoding for chimeric proteins is always present and maps on the 22q- regardless of the type of translocation. We studied two apparently Ph negative CML patients with unusual karyotypes both showing a typical b3a2 rearrangement., Design and Methods: Dual-color fluorescence in situ hybridization (FISH) can visualize BCR and ABL genes and localize the BCR/ABL fusion gene. We used FISH to study the formation mechanisms of variant Ph translocations in two patients., Results: The chimeric BCR/ABL gene was located on a locus other than the expected 22q11 in both patients. In the first case the fusion signal was present on the 9q34 band whereas in the second patient it was detected on chromosome 8, involved in masked Ph formation., Interpretation and Conclusions: The location of the hybrid BCR/ABL gene on chromosomes other than 22q- is a rare event which can only be observed using the FISH technique. When these unusual translocations occur the hypothesis most often put forward is that several consecutive cytogenetic events have taken place. The factors which regulate the formation of these breakpoints have yet to be clarified. The FISH technique allows the identification of chromosome rearrangements that could not otherwise be detected by conventional banding procedures. The location of the hybrid BCR/ABL gene on sites other than 22q11 represents a rare type of variant Ph translocation. The real frequency and clinical significance of such rearrangements need to be investigated.

Background and Objective: The best post-remission therapy for patients with acute lymphoblastic leukemia (ALL) is controversial, and hemopoietic stem cell transplantation (HSCT) is one therapeutic option. The goal of this study is to describe long term results of HSCT in high risk ALL patients., Design and Methods: Between 1978 and 1996, 170 patient with ALL and a median age of 22 years (1-49), underwent an allogeneic HSCT from HLA-identical siblings (n = 149), family mismatched donors (n = 18) or unrelated HLA matched donors (n = 3); 92% of patients had at least one adverse prognostic factor for high risk ALL at diagnosis; one third (33%) were in first remission (CR1) and the majority (85%) received an unmanipulated HSCT with cyclosporin-methotrexate prophylaxis of graft-versus-host disease (GvHD)., Results: After a median follow-up of over 6 years, 59 patients are alive and 111 patients have died of leukemia (46%) or transplant related complications (54%). The actuarial 10 year survival is 53%, 38% and 20%, for patients in CR1, CR2 or advanced phase, respectively. The actuarial survival of patients with (n = 24) of without (n = 46) cytogenetic abnormalities, grafted in CR1/CR2 was respectively 45% and 48% (p = 0.5). The year of transplant had a significant impact in multivariate analysis on transplant related mortality (TRM) (p = 0.0009) but not on relapse (p = 0.3). Chronic GvHD was the most important favorable prognostic factor for survival (p = 0.0014) and relapse (p = 0.0019)., Interpretation and Conclusions: This study confirms that long term survival can be achieved with HSCT in ALL patients, even those with cytogenetic abnormalities. Transplant mortality has been significantly reduced in recent years, whereas leukemia rate relapse has remained unchanged: the latter is influenced by the occurrence of chronic GvHD. Immune intervention post-HSCT may be considered to address this problem.

Background and Objective: Cytogenetic analysis of acute leukemia yields important information which has been demonstrated to be correlated to patient survival. A reference laboratory was created in order to perform karyotype analysis on all cases of acute leukemia enrolled in the AIEOP (Associazione Italiana Emato-Oncologia Pediatrica) protocols., Methods: From January 1990 to December 1995, 1115 samples of children with ALL or AML were sent in for cytogenetic analysis. The results of cell cultures were screened in the Reference Laboratory and then the fixed metaphases were sent to one of the six cytogenetic laboratories for analysis., Results: The leukemic karyotypes of 556 patients were successfully analyzed. An abnormal clone was detected in 49% of cases of ALL and in 66% of AML. In ALL the most frequent abnormality was 9p rearrangement. Other recurrent abnormalities were t(9;22), t(4;11) and t(1;19). In AML t(8;21), t(15;17) and 11q23 rearrangement were the most frequent structural abnormalities. These findings are similar to the results obtained in other multicenter studies using a similar approach., Interpretation and Conclusions: Our data confirm the feasibility of performing cytogenetic analysis in a centralized laboratory on mailed samples of bone marrow and/or peripheral blood; this is very important considering that cytogenetic analysis of neoplastic tissue requires a special laboratory and expert staff.

A case of chronic myelomonocytic leukemia with a reciprocal translocation (12;13)(p13;q14) and other numerical and structural abnormalities is described. Most of the metaphases examined showed duplication of the der(13)t(12;13), leading to trisomy of the translocated segment of chromosome 12. Using fluorescence in situ hybridization we observed that the breakpoint on chromosome 13 is centromeric to the retinoblastoma gene. Since other cases with apparently similar t(12;13) have recently been reported, we conclude that this structural rearrangement may be a rare but non random event in hematologic disorders.

Background: Elderly patients with acute myeloid leukemia (AML) those refractory to induction chemotherapy and those with so-called secondary leukemia have unfavorable prognoses and require innovative therapeutic approaches. Fludarabine allows an increased accumulation of Ara-CTP in leukemic cells and inhibits DNA repair mechanisms; therefore its association with Ara-C and mitoxantrone results in a synergistic effect., Materials and Methods: From May 1993 to February 1996, fludarabine-containing regimens (FLAG and FLANG) were employed as induction therapy in 51 high-risk AML patients. Diagnosis of AML in 22 patients was preceded by a myelodysplastic syndrome lasting more than six months; 8 of the 29 de novo AML cases (28%) were refractory to previous chemotherapy, 9 (31%) were treated for early relapse, 12 (41%) presented poor prognostic factors at diagnosis. The median age was 64 (range 33-76) years and the FAB subtypes were the following: M0 3, M1 5, M2 28, M4 7, M5 8. Forty-eight per cent of patients showed poor prognosis chromosomal abnormalities. FLAG (24 patients) consisted of both fludarabine 30 mg/sqm over 30 minutes followed 4 hours later by Ara-C 2 g/sqm over 4 hours (for 5 days) and G-CSF 300 micrograms/day administered 12 hours before fludarabine, for a total of 5 doses. FLANG (27 patients) had a shorter duration (3 days), reduced Ara-C dosage (1 g/sqm) and administration of mitoxantrone (10 mg/sqm) at the end of Ara-C infusion., Results: Recovery of both neutrophils (PMN > 0.5 x 10(9)/L) and platelets (Plt > 20 x 10(9)/L) required a median of 16 days from the end of therapy. Overall, 30 patients (59%) achieved CR, 6 (11%) PR and 10 (20%) were refractory; 5 (10%) experienced early death (cerebral hemorrhage or infection). The length of complete response ranged from 2 to 26 months with a median follow-up of 8 months. De novo and secondary AML registered 62 and 54% CR rates, respectively. Eight out of 10 patients refractory to conventional schemes achieved CR (80%) but only 3 out of 10 treated for relapse obtained CR (30%)., Conclusions: FLAG and FLANG showed similar activity and toxicity while proving to be highly effective and relatively well-tolerated treatments for high-risk de novo AML. Secondary leukemias seemed to be responsive as well, but the presence of an unfavorable karyotype alteration lowered the response rate.

Background: Cytogenetic abnormalities have been described in a few patients with otherwise typical severe aplastic anemia (SAA), and the possible clonal nature of this disease is a controversial issue., Materials and Methods: Sixty-nine patients with acquired severe aplastic anemia underwent cytogenetic examination on bone marrow cells at the time of diagnosis (n = 34) and/or at least twice after immunosuppressive therapy (IS) (n = 35)., Results: We identified 2 major groups. Group A: 51 patients (74%) were normal and remained normal. Group B: 18 patients (26%) had at least one abnormal cytogenetic analysis. This second group could be further subdivided as follows: (B1) chromosomal abnormalities not present at first examination and acquired in the course of the disease (n = 7); (B2) clonal cytogenetic abnormalities present at first examination and persisting (n = 3); (B3) reversible cytogenetic abnormalities (n = 8). The most frequent abnormality was trisomy 8 (n = 8) followed by monosomy 7 (n = 2); 82% of patients are alive in group A and 61% in group B. Three patients developed acute leukemia, all from group B. This represents 4% of all patients or 17% of those with at least one abnormal cytogenetic test., Conclusions: Thus the majority of SAA patients have normal karyotypes in marrow cells at presentation and at follow-up. Patients with abnormal karyotypes exist and can be further subdivided into those with reversible and those with persistent abnormalities. The latter are at risk of developing myelodysplasia or acute leukemia.

Myelodysplastic syndromes (MDS) are stem cell diseases but it is still controversial whether chromosomal abnormalities occurring in these disorders affect a multipotent stem cell or a committed progenitor. We studied a case of refractory anemia with ringed sideroblasts (RARS) and monosomy 7 in 100% of examined metaphases. Using the fluorescence in situ hybridization (FISH) technique with a probe specific for the centromeric region of chromosome 7, we demonstrated that 15% of BM cells fixed in acetic acid/methanol exhibited a normal diploid karyotype. Applying the FISH technique on PB cells smeared onto a slide, we observed that lymphocytes maintain two chromosomes 7, whereas other leukocytes exhibited monosomy 7. Our study confirms that chromosomal abnormalities found in MDS can occur in cells capable of differentiation along granulocytic and monocytic lineages, but not along the lymphocytic lineage.

Background and Methods: Infantile leukemia is a rare disorder, and few cytogenetic studies have been performed on this condition., Results and Conclusions: The authors present the cytogenetic analyses performed on 14 cases of infantile leukemia. The most frequent chromosomal changes are rearrangements involving 11q (4 cases) and gains of one or more chromosomes 21. Patients with chromosomal rearrangements show a worse prognosis than those with only hyperdiploidy or a normal karyotype, although the difference was not statistically significant due to the small size and short median follow-up.