Clonal chromosome aberrations in Philadelphia-negative cells from chronic myelocytic leukemia patients treated with imatinib mesylate: report of two cases

Imatinib mesylate (tested as STI571), an abl kinase inhibitor, induces sustained, complete hematologic and cytogenetic responses in chronic myelocytic leukemia (CML) patients; however, emergence of clonal chromosomal aberrations in Philadelphia-negative (Ph-) cells during treatment has been reported. We describe two CML patients in chronic phase who presented with complete cytogenetic responses during imatinib mesylate therapy but developed new clonal chromosomal rearrangements in Ph- cells. The first patient presented with a duplication of chromosome 1, dup(1)(q21q42), and the second showed two new clonal aberrations consisting of inv(1)(q12q32) and del(7)(q22) in the same clone.     

Telomere loss in Philadelphia-negative hematopoiesis after successful treatment of chronic myeloid leukemia: evidence for premature aging of the myeloid compartment

Telomere shortening, a well-known marker of aging and cellular stress, occurs under several conditions in the hematopoietic compartment, including aplastic anemia and following iatrogenic noxae. We decided to verify whether pathological telomere erosion also arises in restored Philadelphia-negative (Ph-negative) hematopoiesis following successful treatment of chronic myeloid leukemia (CML). Eighty-one CML patients in complete cytogenetic remission were compared to 76 age-matched healthy subjects. Myeloid cells of CML patients had shorter telomeres than controls (6521 bp vs 7233 bp, p < 0.001). This difference was specific for the myeloid compartment, since it was not observed in lymphoid cells (6774 bp vs 6909 bp, p = 0.620). Acquired Ph-negative cytogenetic abnormalities (p = 0.010), lack of complete molecular remission (p = 0.016) and age (p = 0.013) were independent predictors of telomere shortening. Telomere dynamics were assessed over a median follow-up period of 22 months. We documented accelerated non-physiological ongoing telomere shortening in 17/59 CML patients (28%). Patients experiencing grade 2-4 hematological toxicity, during CML remission possessed significantly shorter telomeres compared to those lacking toxicity (p = 0.005 for any toxicity, p = 0.007 for anemia). CML patients suffer from significant and often ongoing telomere stress resulting in premature and selective aging of the myeloid compartment which might have long-term consequences on function and integrity of Ph-negative hematopoiesis.     

Chromosome 22 breakpoints in variant Philadelphia translocations and Philadelphia-negative chronic myeloid leukemia

The standard t(9;22)(q34;q11) found in Philadelphia (Ph) chromosome positive chronic myeloid leukemia (CML) involves a highly restricted (5.8 kb) chromosome 22 breakpoint cluster region (bcr), which results in the formation of a chimeric gene comprising exons from the 5' end of bcr and protooncogene c-abl coding sequences from chromosome 9. In a survey of 21 patients with hematologic and clinical features of CML we detected rearrangement of the chromosome 22 bcr by gene probe analysis in all cases, including 16 with a standard t(9;22), two with variant Ph translocations [t(10;22)(q26;q11);t(11;22)(p15;q11)], one with a complex Ph translocation [t(9;11;22)(q34;q13;q11)], one with a complex translocation and a masked Ph[t(9;14;22) (q34;q24;q11)], and one Ph-negative case with a t(1;9)(p32;q34). These observations further substantiate the suggestion that, despite karyotypic heterogeneity, a common underlying molecular lesion, the bcr-abl gene chimera, is involved in the disease pathogenesis of CML.     

Cutaneous and pericardial extramedullary hematopoiesis with cardiac tamponade in chronic myeloid leukemia

A 48-year-old woman with Philadelphia chromosome-positive chronic myeloid leukemia developed skin and pericardial extramedullary hematopoiesis. The echocardiogram revealed massive pericardial effusion with signs of tamponade. The cytocentrifuge preparation of pericardial fluid demonstrated all three hematopoietic components. Assays for the granulocyte-macrophage progenitor cells and erythroid progenitors on her pericardial fluid gave rise to colony numbers comparable to those of normal bone marrow cells. The patient was successfully treated with pericardiocentesis followed by short-term indwelling catheter drainage and administration of hydroxy-urea. There was no reaccumulation of fluid at ten months.     

Case report and literature review: a rare patient with chronic myeloid leukemia and chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML) are the most common leukemias of the elderly. However, the sequential occurrence of CML followed by CLL in the same patient is extremely rare. In the present report, a 71-yr-old man was diagnosed with Philadelphia (Ph) chromosome positive CML and treated with imatinib mesylate. He went into morphologic, cytogenetic, and molecular remission. Seven years after the diagnosis of CML, he developed CLL. We describe the morphologic, immunophenotypic, cytogenetic, and molecular findings in this patient.     

The combination therapy of imatinib and dasatinib achieves long-term molecular response in two imatinib-resistant and dasatinibintolerant patients with advanced chronic myeloid leukemia

For patients with chronic myeloid leukemia (CML) failing imatinib therapy, second-generation tyrosine kinase inhibitors (TKIs) are recommended. Here, we describe two patients with advanced CML who failed imatinib therapy and did not tolerate the recommended dose of dasatinib, but then achieved a major molecular response with the combination of imatinib and dasatinib with no significant extramedullary toxicity. Our observations suggest that combination of TKIs may provide an additive/synergistic antileukemic effect.     

慢性粒细胞白血病患者染色体检查及预后意义探讨

目的探讨慢性粒细胞白血病(CML)患者染色体变化的有关特点及预后意义.方法染色体制备采用骨髓细胞短期培养法,应用G、R显带技术对85例CML患者的骨髓细胞进行遗传学分析.结果 85例CML患者中,78例检出典型Ph染色体,占91.76%,3例为变异Ph易位,占3.53%,4例Ph染色体阴性,占4.71%,10例核型呈嵌合状态,13例出现附加染色体异常,主要为 8,i(7), Ph, 22, 12等,其中9例为加速和急变期患者,占64.29%.结论 CML是一种高度异质性疾病,非随机的附加染色体异常与患者临床分期高度相关.CML患者进行染色体分析对于疾病的诊断及鉴别、指导临床治疗、判断预后具有重要意义.     

急性白血病、慢性髓细胞白血病及骨髓增生异常综合征患者染色体分析

目的探讨染色体分析在急性白血病（AL）、慢性髓细胞白血病（CML）及骨髓增生异常综合征（MDS）诊断及预后判断中的价值。方法采用骨髓细胞短期培养法,应用G、R显带技术对238例AL、CML及MDS患者进行染色体分析。结果56.30%的患者有染色体异常,其中数目异常占6.30%,结构异常占39.08%,复杂异常占10.92%;各组患者中CML组异常检出率最高,占总病例的34.87%;AL组染色体畸变最为复杂,累及除3,4,5,10及X以外的所有染色体,11例患者出现了特异性染色体畸变,与患者预后相关;CML加速/急变期出现了附加染色体异常;核型异常的MDS患者均检出了8三体,7例为单纯8三体,2例RAEB-T患者均为复杂异常。结论染色体检查对于疾病诊断与鉴别、指导临床治疗、判断预后等具有重要意义。     

Coexistence of chronic myeloid leukemia and hairy cell leukemia of common clonal origin

The history of a forty year old patient is presented who was admitted with a clinical picture of chronic myeloid leukemia (CML). Laboratory findings, bone marrow morphology and molecular investigations supported this diagnosis, including b3/a2 as well as b2/a2 chimeric mRNA expression in support of a Philadelphia chromosome positive chronic myeloproliferation. In a fraction of the bone marrow content, however, an infiltrate different from that of CML could be seen. In addition, the morphology, cytochemistry, immunophenotyping and molecular analysis indicated that the coexisting neoplasia is hairy cell leukemia (HCL). Cell lineage specific interphase cytogenetic analysis proved a clonal relationship between the two neoplasias in a way that the HCL arose from one of the B-cells which, based on two cytogenetic markers, belonged to the original CML clone.     

GSTT1 copy number gain is a poor predictive marker for escalated-dose imatinib treatment in chronic myeloid leukemia: genetic predictive marker found using array comparative genomic hybridization

In a study population of 45 patients who were previously enrolled in an imatinib dose escalation trial, genome-wide screening for regions of genetic gains and losses was performed using array comparative genomic hybridization (aCGH). Early molecular response (EMR), defined as >50% reduction in the ratio of BCR-ABL1 to ABL1 within 6 months after dose escalation, was a major endpoint for analysis. After aCGH analysis, copy number change of four genes was investigated in 52 patients as a validation. Copy number gain in 16p11.2 was more frequently observed in patients with EMR than in patients who failed to achieve EMR (P = 0.034). A tendency for increased copy number in 22q11.23 in patients without EMR and for decreased copy number in 17q12 in patients with EMR was observed (P = 0.072 and P = 0.070, respectively). For GSTT1, in 22q11.23, copy number gain was observed in patients without EMR (P = 0.035). GSTT1 copy number gain was related to short time to treatment failure (TTFx) in patients without BCR–ABL1 mutations (P = 0.007). In multivariate analysis, GSTT1 copy number gain was an independent predictive factor for short TTFx (P = 0.020). We conclude that chromosome regions 16p11.2, 22q11.23, and 17q12 are potential locations related to response in imatinib dose escalation therapy for CML. GSTT1 copy number gain is a genetic change affecting outcome in this setting.     

Telomerase activity in patients with chronic myeloid leukemia and lymphoma

Telomeres are repeated DNA sequences, positioned at the ends of chromosomes and are essential for the stable maintenance of chromosomes. The telomere length serves as a mitotic clock determining the remaining replicative capacity of the cell. Telomeric sequences are lost during each cell division, leading to a process thought to contribute to senescence and cell death. The enzyme telomerase adds 5'-TTAGGG-3' repeats to the mammalian telomeres and maintains the telomere length. Telomerase is normally inactive in most somatic cells but telomerase activity is observed in malignancies. In this study telomerase activity was analyzed in patients with chronic myeloid leukemia (CML) and lymphoma by PCR and ELISA. This approach combines highly specific amplification of the telomerase-mediated elongation products with nonradioactive detection in a highly sensitive photometric ELISA. The PCR products were also analyzed by Southern blotting. The telomerase-specific PCR products were seperated by electrophoresis and transferred to a nylon membrane with subsequent detection of the biotinylated amplificates. High activity levels were detected in 17 CML ( 34%) patients. On the other hand, no activity was observed in lymphoma patients. An increase in the shorter telomeric bands was observed in CML patients who displayed a high level of telomerase activity. In contrast to the low enzyme activity, evidence of telomeric repeats were also found in some lymphoma patients by Southern blotting. This may indicate that lymphoma cells may make use of different pathways for maintaining the length of their telomeres.     

Complex chromosomal rearrangements in patients with chronic myeloid leukemia

During progression of chronic myeloid leukemia (CML) from the chronic to the accelerated phase and/or blast crisis, clonal evolution with nonrandom secondary aberrations such as +8, +Ph, i(17q), +19, -Y, +21, +17, and -7 is frequently observed. Complex chromosomal rearrangements (CCR) are rather rare, and the significance and frequency of different anomalies are poorly understood. The aim of this study was to determine the chromosomes and chromosomal regions which are involved in CCR during progression of the disease and the frequency of nonrandom changes. Conventional cytogenetics, FISH, and multicolor FISH (mFISH) were used to study karyotypes of 18 CML patients with CCR ascertained by G-banding. Most often involved in CCR were chromosomes 2 (x6); 3, 7, and 17 (x5); 1 and 4 (x4); and 5, 6, 11, and 12 (x3); regions 1q, 2q, 5q, 7p, and 17p; and breakpoints 17p11.2 (x3) and 7p15 (x2). There were no recurrent complex translocations. The present findings demonstrate the very high instability of the genome of malignant cells at the chromosomal level. Precise determination of breakpoints involved in CCR can give new dimension to the understanding of genetic mechanisms which play role in progression of malignant disease.     

Myelofibrosis in patients with chronic myeloid leukemia treated with interferon-alpha

Trepanobiopsies of the bone marrow were studied in 46 patients in a chronic phase of chronic myeloid leukemia in different periods after the beginning of interferon-alpha therapy. Progression of myelofibrosis was observed in 2 cases only. Regression of myelofibrosis was observed in 14 cases of 29 (34.2%). A negative correlation between reticulin myelofibrosis and response to therapy was found. Disappearance of diffuse reticulin myelofibrosis in all cases was followed by a cytogenetic response.