Detection of BCR/ABL rearrangements in adult acute lymphoblastic leukemia using a highly sensitive interphase fluorescence in situ hybridization method (D-FISH).

INTRODUCTION: One hundred-and-six adult cases of acute lymphoblastic leukemia were prospectively investigated using a highly sensitive interphase fluorescence in situ hybridization assay which utilizes DNA probes that detect a double BCR/ABL fusion signal (D-FISH) in cells carrying the t(9;22) to evaluate the reliability and specificity of this method for the detection of the Ph translocation. The results were compared with those obtained in the same cases by conventional cytogenetics and by reverse-transcription polymerase chain reaction. MATERIALS AND METHODS: The study was performed using DNA probes that span the common breakpoints of the t(9;22) translocation and that detect a double BCR/ABL fusion in cells carrying this karyotypic anomaly, one on the abnormal chromosome 9 and one on the Ph chromosome. RESULTS: Interphase D-FISH detected a high number of rearranged cases (22/106) compared to conventional cytogenetics (15/106) and RT-PCR (21/106). CONCLUSION: Interphase D-FISH emerges as a reliable, fast and relatively inexpensive tool for the detection of BCR/ABL rearrangements in adult ALL patients at diagnosis. It has a sensitivity clearly higher than conventional karyotyping and it may prove also superior to that of RT-PCR in cases with unusual BCR/ABL breakpoints. Our results suggest that D-FISH might be considered as the initial test for the diagnosis of Ph+ adult ALL.

Use of dual-color interphase FISH for the detection of inv(16) in acute myeloid leukemia at diagnosis, relapse and during follow-up: a study of 23 patients.

The value of dual-color fluorescence in situ hybridization (FISH) for the detection of inv(16), using two contigs of cosmid probes mapping on both sides of the chromosome 16p breakpoint region, was evaluated in 23 acute myeloid leukemias (AML) in different phases of the disease. At diagnosis interphase FISH detected inv(16) in 19/19 (100%) cases with conventional cytogenetics (CC) evident aberration and excluded the rearrangement in two patients with CC suspected inv(16). Moreover, it also identified an associated del(16p) in two patients. At relapse, it revealed the inv(16) in 8/8 (100%) studied cases. These results were concordant with those of reverse transcriptase-polymerase chain reaction (RT-PCR). From 13 patients who obtained at least one complete remission (CR), 31 follow-up samples were analyzed using interphase FISH. Twenty-nine specimens scored negative for inv(16) and two were positive. RT-PCR detected CBFbeta/MYH11 transcripts in four of the nine CR samples analyzed, being more sensitive than interphase FISH. Eight of the 13 patients relapsed at a median time of 6.5 months (range 1-15) from the last negative FISH analysis. Of the two patients with positive FISH in CR, one relapsed soon after. At diagnosis and relapse, interphase-FISH proved to be an effective technique for detecting inv(16) appearing more sensitive than CC. Prospective studies with more frequent controls and possibly additional FISH probes are needed to assess the value of interphase FISH for minimal residual disease (MRD) and relapse prediction.

Sequential molecular monitoring of chimerism in chronic myeloid leukemia patients receiving donor lymphocyte transfusion for relapse after bone marrow transplantation.

Recent observations of chimerism in patients relapsed following an allotransplant suggest the persistence of immunotolerance, thus offering a biologic rationale for the use of donor lymphocyte transfusion (DLT). In this study, we have analyzed by PCR amplification of several VNTR regions, sequential bone marrow and peripheral blood DNA samples in four patients who received DLT for CML relapse after bone marrow transplantation. Prior to DLT, all patients showed mixed chimerism in peripheral blood cells while two had mixed chimerism and two no chimerism in the BM. None of these four patients showed evidence of chimerism at the cytogenetic level (all had 100% +ve metaphases). After DLT, a complete hematologic and molecular remission (ie disappearance of the BCR/ABL fusion transcript) was obtained in the two patients who had bone marrow mixed chimerism prior to DLT. The two patients without evidence of marrow chimerism prior to DLT converted to a pattern of mixed chimerism after DLT, but both developed a severe bone marrow aplasia occurring at day 56 and 36, respectively. With regard to the sequential analysis of bone marrow chimerism after DLT we observed that: (1) the disappearance of BCR/ABL +ve cells paralleled the conversion to a pattern of full donor chimerism; and (2) the time interval to achieve CR was inversely correlated with the percentage of donor DNA in bone marrow. In conclusion, we have shown here that the assessment of bone marrow pre-DLT chimerism by PCR analysis might predict the response in patients with favorable characteristics, and also might identify patients at high risk of developing severe myelosuppression.

Combined cytogenetic, FISH and molecular analysis in acute promyelocytic leukaemia at diagnosis and in complete remission.

This study reports the results of a simultaneous application of cytogenetic fluorescence in situ hybridization (FISH) and molecular analysis (RT-PCR) in 28 APL cases (23 M3 and five M3v; 26 studied at diagnosis and two at relapse). FISH on metaphases identified the t(15;17) in all cases who were positive for the PML/RAR alpha transcript by RT-PCR. Conventional cytogenetics revealed the t(15;17) in only 68% of cases. However, it enabled the detection of additional chromosome changes in five cases, three of whom were M3v. 11 patients were also investigated during complete remission (CR) by both FISH and RT-PCR, in order to evaluate residual disease; the duration of CR at the time of analysis ranged between 1 and 16 months, with three patients being studied twice. Comparison of RT-PCR and FISH results showed a very good correlation. In fact, of the 10 samples which were RT-PCR positive for residual disease, all were also recognized by interphase FISH, and eight were positive by metaphase FISH. Of the three samples negative at RT-PCR, all were also negative at the interphase FISH. The results of this study indicate that: (a) the t(15;17) is present in all cases positive for the PML/RAR alpha rearrangement, thus in virtually all true APLs; (b) standard cytogenetics, capable of unravelling the t(15;17) in only 68% of cases, enables recognition of additional chromosome changes of potential clinical and prognostic significance; (c) FISH on interphase nuclei is a reliable tool for the monitoring of residual disease, with a sensitivity greater than that of FISH on metaphase cells and superimposable to that of RT-PCR.

Acute leukemia presenting a variant Ph chromosome with p190 expression, dup 3q and -7, developed after malignant lymphoma treated with alkylating agents and topoisomerase II inhibitors.

We describe the occurrence of a variant Ph chromosome (v-Ph) in a therapy-related acute leukemia (s-AL), developed after 8-year treatment for a NHL with alkylating agents, anthracyclines and topoisomerase II inhibitors. The v-Ph originated from a complex t(2;9;22) translocation, expressed a p190bcr-abl fusion protein, and was associated to other specific changes, such as dup(3) (q21q26) and -7. The s-AL, apparently not preceded by a dysplastic phase, presented with signs of trilineage dysplasia with 10% micromegakaryocytes; it was classified as M5 according to FAB. The complex genetic changes observed in the present case may reflect distinct leukemogenic effects by different chemotherapeutic agents.

Application of fluorescence in situ hybridization in defining a complex t(9;21;22) Ph formation.

We describe the application of fluorescence in situ hybridization (FISH) in a case of suspected chronic myelogenous leukemia (CML), cytogenetically characterized by a t(21;22) with no clear involvement of chromosome 9. The dual color FISH technique, performed using specific painting probes for chromosomes 9,21,22 and a BCR/ABL translocation probe, enabled us to confirm the diagnosis of CML by detecting the BCR/ABL rearrangement on chromosome 22q and the involvement of chromosome 9 in a variant translocation t(9;21;22).

Trisomy 14 in hematologic diseases. Another non-random abnormality within myeloid proliferative disorders.

Two cases of myelodysplastic syndrome (MDS) and a case of acute nonlymphoblastic leukemia (ANLL) with a trisomy 14 are presented. The series of results derived from our cases, and those previously reported, strongly suggest that this anomaly may be another nonrandom change, confined within myeloid disorders and associated with patients' advanced age, marked tendency to bone marrow dysplastic features, normal platelet values, and not unfavorable prognosis.

Management of chronic myeloid leukemia in chronic phase with autologous stem cell transplantation and alpha-2 interferon: cytogenetic and clinical results.

Forty-eight patients with chronic myeloid leukemia (CML) in chronic phase (CP) were treated by autologous stem cells transplantation (ASCT) and alpha Interferon (IFN) with three approaches: 1) ASCT at diagnosis followed by IFN, 2) ASCT post IFN with cells collected after an interval from IFN discontinuance, followed by IFN, 3) ASCT in patients selected by cytoconversion obtained with IFN, performed soon after IFN discontinuance. Following ASCT, a major karyotype response (more than 65% Ph1 negative cells, MKR) was observed at least once in 40%, 53% and 83% of patients from the three groups, respectively. At last follow-ups (median 39, 40 and 21 months, respectively) 19%, 13% and 67% of patients still present a MKR with 2 patients from group 1 and 4 patients from group 3 being 100% Ph' negative. Projected survival from diagnosis is 77% at 52 months for patients from group 1 and 47% at 75 months for patients from group 2. Present data indicate that 1) IFN can stabilize results obtained with ASCT, 2) ASCT can potentiate responses to IFN, 3) combined ASCT and IFN can improve survival. Longer follow-up of patients and randomized studies are required to define the real impact on disease outcome by these treatment approaches.

Ph-negative and bcr-negative atypical chronic myelogenous leukemia: biological features and clinical outcome.

We report the clinical, hematologic, cytogenetic, and molecular characteristics of 13 patients with Philadelphia-negative (Ph-), bcr-negative atypical chronic myelogenous leukemia (CML). In the majority of cases, the phenotypic features at presentation resembled those of typical CML. However, these patients presented with a higher median age, lower median hemoglobin levels, and lower leukocyte and platelet counts than patients with Ph-positive CML. Cytogenetic analysis showed an abnormal karyotype in only one case. Southern blot investigation, using probes exploring the entire M-bcr region, demonstrated the absence of genomic bcr-abl rearrangements. The assessment of clonality in five patients (study of X-methylation patterns in females heterozygous at the DXS255 locus) indicated the proliferation of a monoclonal cell population. Disease evolution was mostly characterized by bone marrow failure, extramedullary infiltrates, and poor response to chemotherapy, without evidence of overt acute transformation. Our observations suggest that some hematologic and clinical features and the modalities of disease progression are presently the most helpful factors in distinguishing these bcr/abl-negative patients from those with typical bcr+CML. The differences existing also with chronic myelomonocytic leukemia (CMMoL), allow the consideration of ph-/bcr- CML as a separate entity, the nature of which remains to be elucidated.

Interferon therapy for Ph1 positive CML patients relapsing after T cell-depleted allogeneic bone marrow transplantation.

Eighteen chronic myeloid leukemia patients with hematological (four patients) or only cytogenetic (14 patients) relapse occurring after T cell-depleted allogeneic bone marrow transplantation (BMT) have been treated with alpha 2b interferon (IFN) at a starting dose of 5 x 10(6) i.u./m2 subcutaneously three times a week. All four patients with hematological relapse achieved long-lasting hematological remission without reduction of bone marrow Ph1 positive cells. When IFN was started the median percentage of bone marrow Ph1-positive metaphases was 50% (range 9-100) for the 14 patients with cytogenetic relapse. Twelve (85.7%) of these patients are alive with a median follow-up of 25 months (range 20-37 months) from cytogenetic relapse and 33 months (range 27-49 months) from BMT. Six (43%) of the 14 patients progressed to hematological relapse and eight patients (57%) are still in hematological remission with two patients achieving complete cytogenetic remission confirmed at molecular level by disappearance of the M-BCR rearranged band. IFN therapy may be a good alternative to conventional chemotherapy for transplanted CML patients with hematological relapse and the treatment of choice for patients with a persistent cytogenetic relapse occurring after T cell-depleted BMT.

Cytogenetic follow-up after allogeneic bone-marrow transplantation for Ph1-positive chronic myelogenous leukemia.

Serial cytogenetic studies were carried out on 36 patients with Ph1-positive chronic myelogenous leukemia treated with allogeneic bone-marrow transplantation from unlike sex (21 patients) or like sex (15 patients) donors. Fourteen of the 21 sex-mismatched and 12 of the 15 sex-matched donor marrows were T cell depleted. Disease relapse was documented in 19 of the 26 patients who received T cell-depleted marrow, and in none of the 10 patients who received non-T cell-depleted marrow. In the group of patients with unlike sex donor, a triple donor/normal recipient/Ph1-positive recipient or a double donor/Ph1-positive recipient chimerism was documented during the subsequent months, while on alpha-interferon treatment for relapse. Two of these patients subsequently showed a complete disappearance of the Ph1 chromosome. Unstable and/or stable, clonal or non-clonal chromosome changes were detected in Ph1-positive cells from 12 of the 19 patients who relapsed. Analysis of the identified stable changes showed a non-random distribution of breakpoints with clustering to chromosome nos. 1, 4, 7 and 12.

Alpha-2b-interferon as single therapy for patients with chronic myeloid leukemia relapsing after T-cell depleted allogeneic bone marrow transplantation.

20 CML patients with hematological (5 pts) or only cytogenetic (15 pts) relapse occurring after allogeneic BMT have been treated with alpha-2b-interferon (IFN) at a starting dose of 5 x 10(6) IU/m2, subcutaneously, three times a week. All 5 patients with hematological relapse achieved hematological remission without reduction of bone marrow Ph1-positive cells. With a median follow-up of 43 months (range 6-48) from the hematological relapse, 3 patients are alive and 2 patients died from non-lymphoid blast crisis. 7 out of 15 patients with only cytogenetic relapse remain in hematological remission at a median of 37 months (range 3-45) from cytogenetic relapse, with 2 patients achieving complete cytogenetic remission confirmed at the molecular level by disappearance of the bcr rearranged band. With a median follow-up of 21 months (range 6-46), 8 patients progressed from cytogenetic to hematological relapse: 4 patients died from blast crisis and the other 4 patients are currently alive in chronic phase. For the 15 patients, the actuarial survival from BMT is 71% at 5 years.

Acute myeloblastic leukemia with t(8;21) following Philadelphia positive acute lymphoblastic leukemia.

A patient with Philadelphia positive (Ph'+) acute lymphoblastic leukemia (ALL), in remission for over 4 years, developed an acute myeloblastic leukemia (AML), M2-type. During the second disease, the blast cells displayed a typical t(8;21)(q22;q22) translocation, in the absence of the Ph' chromosome. This is the first observation in the same patient of two leukemias displaying different cell phenotypes and each associated to one of the most characteristic chromosome changes. Cytogenetic characteristics and clinical aspects of the diseases are suggestive for the occurrence of two independent leukemic processes.

Molecular characterization of Ph' + hybrid acute leukemia.

The configuration of the immunoglobulin heavy chain (IgH), T-cell receptor (TcR) beta and gamma chain regions, and the major breakpoint cluster region (M-bcr) genes were analysed in four cases of Ph' + acute leukemia (AL). Monoclonal rearrangements of the IgH region were detected in three cases exhibiting two phenotypically distinct cell populations (i.e. one lymphoid and one myeloid. In one of these cases, identical genetic events were observed by molecular analysis of FACS separated blasts. Multi-lineage rearrangements involving also the TcR gamma gene were observed in a biphenotypic AL showing co-expression of markers. The lack of rearrangements within the M-bcr gene, together with demonstration in one case of the Ph' + AL specific p190 protein product, pointed against the occurrence of chronic myeloid leukemias presenting in blastic transformation. Our results imply that such cases are to be considered as true AL and should therefore be included in the definition of hybrid AL.

Cytogenetic and molecular characterization of a masked Philadelphia chromosome in chronic myelocytic leukemia.

A case of typical chronic myeloid leukemia with an apparently Philadelphia-negative karyotype is described. Molecular studies confirmed the cytogenetic interpretation of a standard Ph rearrangement, with secondary involvement of 22q- in a translocation with chromosome #5, leading to its masking. The chromosomal regions engaged in the standard t(9;22) were not modified and the molecular rearrangements of Ph were also conserved. The hematologic and clinical features were apparently not influenced by the events leading to the masking of Ph. Further similar observations with both cytogenetic and molecular characterization are needed to better identify the possible clinical consequences of these complex changes.

The karyotype of blastic crisis.

The nonrandomness of chromosome clonal evolution in blastic crisis of chronic myeloid leukemia is well established, with three major changes [+8, +Ph, i(17q)] occurring alone or in combination in over 70% of the patients. The chromosome changes observed in different tissues may reveal the origin of the abnormal clones, as well as provide evidence for distinct or common evolution by different cell populations. The significance of the chromosome abnormalities and their relationship to blastic conversion are discussed. In general, chromosome evolution may be considered a rather reliable predictive or diagnostic parameter of blastic crisis but both the nature and the subsequent behavior of abnormal clones appear to be of critical value. As to the clinical/chromosome correlations, a few major points have emerged: the i(17q) aberration is mostly associated with signs of myeloid differentiation of blasts and a marked basophilia; it is mainly observed in the late stage of the disease, but overall median survival of patients with this marker is usually long; more atypical or complex changes usually are associated with a worse prognosis; patients with only a Ph in their blasts may have a longer survival, at least in some cytologic subgroups; and d) the loss of the Y chromosome seems to protect the cell against further clonal evolution. Finally, the relevance of the chromosome changes in the multistage process of blastic conversion is discussed, and the breakpoints of secondary changes recorded so far are reviewed and examined. It appears that certain chromosome regions are more often affected; these might contain genes of critical importance for the final malignant progression. Molecular biology may provide insight, in the future, on the nature and expression of involved genes.

A case of Burkitt lymphoma-L3ALL with t(8;14) translocation, developed 10 years after Hodgkin's disease.

We report the case of a 38-year-old man, previously treated for Hodgkin's disease (HD) with chemo-radiotherapy who, 10 years later, developed a Burkitt lymphoma (BL) as a tumour mass of the ascendent colon and regional lymph nodes and, subsequently, on leukaemic bone-marrow cells, on the basis of histological, immunological (B phenotype, IgM-lambda) and cytogenetic, translocation t(8;14) features. The patient died a few days later; at autopsy no evidence of HD was found. This is the 2nd case of BL developing after HD so far described. The relationship between the 2 diseases is discussed and the importance of the immunodepression in the pathogenesis of the secondary Burkitt lymphoma is emphasized.

Cytogenetic findings in acute promyelocytic leukaemia. A report of 25 cases.

Cytogenetic analyses of bone marrow cells were carried out by means of direct technique and short-term cultures in 25 acute promyelocytic leukaemia (APL) patients. 16 were affected by the hypergranular form and 9 by the M3-variant. The t(15;17) was documented at diagnosis in 15 patients. In addition, 2 cases, in which an M3 morphology and a normal karyotype on direct preparation were found at diagnosis, disclosed the chromosome anomaly in cultured cells at relapse, in concomitance with a change of blast morphology to the M3-variant. However, the t(15;17) was a consistent feature in 5 of the 15 patients with cells analysed on direct preparations only and in all cases who had successful bone marrow cultures. Overall, the 15;17 translocation was detected in 7 out of 9 patients with the M3-variant and in 8 out of 16 patients with typical M3. Whenever the chromosome preparations were made after culture, 7/7 had the translocation in the M3-V group and 5/5 in the M3 group. No obvious differences in clinical features or outcome were evident in the patients, irrespective of their cytogenetic findings.