Emergence of new clonal abnormalities following interferon-alpha induced complete cytogenetic response in patients with chronic myeloid leukemia: report of three cases

Philadelphia (Ph) chromosome-positive chronic myeloid leukaemia relapsing as Ph-negative leukaemia after allogeneic bone marrow transplantation

Two patients with Philadelphia chromosome-positive (Ph(+)) chronic myeloid leukaemia (CML) relapsed 1.5 and 5 years after allogeneic bone marrow transplantation (BMT). Although the leukaemias were of recipient origin, t(9;22) could no longer be detected using conventional cytogenetics/fluorescence in situ hybridization or molecularly. Both patients responded to immunotherapy with donor lymphocytes/peripheral blood stem cells, although one patient ultimately relapsed again. These patients were similar to the occurrence of Ph(-) leukaemias previously described in Ph(+) CML after treatment with interferon or autologous BMT, and might be relevant in the pathogenesis and monitoring of treatment after BMT in CML.

Philadelphia-positive chronic myelogenous leukemia with a 5q-- abnormality in a patient following interferon-alpha therapy

In this report, we describe a rare 5q--/CML association in a patient with Ph-positive chronic myelogenous leukemia (CML) who achieved complete cytogenetic response on interferon-alpha (IFN-alpha) treatment, but who developed a new clone in the blastic crisis. The patient was treated with interferon-alpha beginning in 1996 and a serial chromosome and molecular study was performed over the clinical course of the disease. The patient remained in complete hematologic and cytogenetic remission until November 1998, when a reverse transcriptase PCR study performed on the bone marrow and peripheral blood cells was negative for chimeric BCR/ABL mRNA. The treatment was discontinued until April 1999, when the patient developed acute transformation of the disease. In June 1999, cytogenetic examination showed the development of a new clone, consisting of the deletion of the long arm of chromosome 5 in addition to the standard Ph translocation. The unusual association of a Ph with an abnormality usually observed in a secondary myeloproliferative disease raises the question of whether the new finding is treatment-induced or part of the disease process and casually related to the acute transformation.

Chronic myelogenous leukaemia with p185(BCR/ABL) expression: characteristics and clinical significance

We investigated the significance of p185BCR/ABL expression in patients with chronic myelogenous leukaemia (CML) in relation to disease features, therapy and outcome. Results of Western blot analysis for 1384 patients referred with a diagnosis of CML to our institution from 1989 to 1997 were reviewed. Clinical characteristics, results of cytogenetic analysis and RT-PCR for BCR rearrangement were analysed. Five patients with Ph-positive CML expressing the p185BCR/ABL hybrid protein were identified. By RT-PCR, bone marrow specimens of these patients were confirmed to have an e1a2 junction. The median age at diagnosis of these patients was 55 years (range 43-76). All had elevated white cell counts at diagnosis (median 50 x 109/l, range 11.7-163 x 109/l). Four patients had monocytosis (range 10-16%) with a low neutrophil/monocyte ratio in the peripheral blood (range 3.4-5.7). Patients presented with various stages of the disease (two in chronic-phase CP, two in accelerated-phase AP, and one in blastic-phase BP). The clinical course and therapy of the patients varied, with one patient receiving hydroxyurea only, three patients receiving hydroxyurea followed by interferon-alpha based regimens and bone marrow transplantation. The patient presenting in BP was treated with combination chemotherapy. The clinical outcome of the patients was also varied with one patient alive and in complete remission (with complete cytogenetic remission after transplant) and four patients dead after progression to more advanced stages. We conclude that patients with Ph-positive p185BCR/ABL CML frequently present with monocytosis and a low neutrophil/monocyte ratio in the peripheral blood, aiding the speculation that the presence of the p185BCR/ABL hybrid protein may contribute to a phenotype intermediate between CML and CMML. Of interest, the only other specific clinical feature identified was the absence of splenomegaly in four of five patients. There was no definite association with transformation to lymphoid blast phase.

Emergence of unusual cytogenetic abnormalities under interferon-alpha therapy in patients with chronic myelogenous leukemia

New treatments that may change the course of a disease or have potential carcinogenicity can result in the emergence of new cytogenetic or clinical disorders. We report here the cytogenetic evolution of 52 cases of Philadelphia (Ph)-positive myelogenous leukemia (CML) receiving interferon-alpha (IFN-alpha) therapy compared with that of 59 Ph-positive CML cases treated with busulfan (BU) or hydroxyurea (HY). Twenty-one percent of the CML patients receiving IFN-alpha displayed unusual secondary abnormalities, among which alteration of the long arm of chromosome 3, del(7), and del(9) were recurrent. The frequency of these unusual secondary changes was significantly higher than in CML cases after Bu or Hy treatment (P = 0.02). Three of the 11 IFN-alpha-treated CML patients displayed cytogenetic evolution in the chronic phase and, in two cases, the cytogenetic findings were transient, inasmuch as they disappeared upon withdrawal of IFN-alpha. In addition, a majority of cytogenetic abnormalities involved chromosome 3 at bands 3q21 and 3q26, which corresponds to the locus of EVI1, a gene implicated in the development or progression of human myeloid leukemias. Possible explanations include: toxicity of IFN-alpha by effect on bone marrow stroma, immune-modulating effects of IFN-alpha, and mutagenic effects of IFN-alpha. The mechanisms underlying these cytogenetic changes remain to be elucidated. However, our data suggest that IFN-alpha induces additional cytogenetic abnormalities even in the chronic phase through its immune-modulating effects and that these unusual cytogenetic abnormalities do not alter the history of CML.

Transient monosomy 7: a case series in children and review of the literature

BACKGROUND

Monosomy 7 and deletions of the long arm of chromosome 7 [del (7q)] are recurrent, nonrandom chromosomal abnormalities associated with both de novo and therapy-related myelodysplastic syndromes (MDS). The overall prognosis for children and adults with these chromosomal abnormalities is poor. In the current report, the authors present five children with MDS associated with monosomy 7/del(7q) who achieved spontaneous hematologic disease remission as well as a review of the literature.

METHODS

Five children with either de novo or treatment-related MDS who achieved spontaneous hematologic disease remission are presented. Relevant clinical, cytogenetic, and fluorescent in situ hybridization data are included.

RESULTS

All patients were boys. Three had de novo MDS whereas two others previously had received chemotherapy for another malignancy. Four patients achieved spontaneous and durable hematologic disease remission that was associated with cytogenetic disease remission in all three patients tested. The fifth patient developed a disease recurrence and died with evidence of clonal evolution after a long interval of hematologic and cytogenetic remission.

CONCLUSIONS

A subset of children who develop MDS associated with monosomy 7 or del(7q) achieve spontaneous hematologic and cytogenetic improvement. Although this appears to be uncommon, further data are needed to determine the percentage of patients who improve without therapy and to define clinical characteristics that may predict this clinical outcome. These findings suggest that monosomy 7/del(7q) is insufficient to produce full leukemic transformation.