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Expression of CD7, ELA-2, PR-3, and the polycomb group gene BMI-1 reflects the intrinsic heterogeneity and predicts prognosis of patients with chronic myeloid leukemia (CML) who were not treated with allogeneic stem cell transplantation (allo-SCT). This study investigated whether expression of these genes determined outcome following allo-SCT in a cohort of 84 patients with chronic-phase (CP) CML. We found that patients expressing BMI-1 at a "high" level before allo-SCT had an improved overall survival (P = .005) related to a reduced transplantation-related mortality. In multivariate analysis, when adjusted for the European Group for Blood and Marrow Transplantation (EBMT)-Gratwohl score and other prog-nostic factors, there was an independent association between BMI-1 expression and grades 2 to 4 acute graft-versus-host disease (relative risk [RR] = 2.85; 95% confidence interval [CI], 1.3-6.4; P = .011), suggesting that BMI-1 measured prior to allo-SCT can serve as a biomarker for predicting outcome in patients with CP-CML receiving allo-SCT, and may thus contribute to better therapeutic decisions.

Dasatinib, a potent inhibitor of BCR-ABL in vitro, is effective for patients with chronic myelogenous leukemia (CML) resistant or intolerant to imatinib. To provide a more definitive assessment of dasatinib in chronic-phase (CP)-CML, we report extended follow-up of a phase II trial, presenting data for the entire patient cohort (N=387). Dasatinib (70 mg) twice daily was administered to patients with imatinib-resistant or -intolerant CP-CML. With median follow-up of 15.2 months (treatment duration, <1-18.4 months), a complete hematologic response was attained or maintained in 91% of patients. A major cytogenetic response (MCyR) was attained or maintained by 59% (52% imatinib resistant and 80% imatinib intolerant); this was complete in 49% of patients (40% imatinib resistant and 75% imatinib intolerant). Of 230 patients achieving an MCyR, 7 experienced disease progression. Fifteen-month progression-free survival was 90% while overall survival was 96%. Grade 3/4 thrombocytopenia and neutropenia were reported in 48 and 49% of patients, respectively. Non-hematologic toxicity (any grade) consisted primarily of diarrhea (37%), headache (32%), fatigue (31%), dyspnea (30%) and pleural effusion (27%). Pleural effusions were classified as grade 3 in 6% of reported events, with no incidence of grade 4. Dasatinib is associated with high response rates in patients with imatinib-resistant or -intolerant CP-CML.

The majority of patients with chronic-phase (CP) chronic myeloid leukemia (CML) who are treated with Bcr-Abl tyrosine kinase inhibitors such as imatinib and dasatinib achieve cytogenetic disease remission (ie, Philadelphia chromosome-positive cells undetectable by cytogenetic evaluation). However, more sensitive methods are required for monitoring residual disease (ie, molecular monitoring of BCR-ABL transcript levels). It is generally accepted that molecular responses have prognostic significance. Patients with CP CML who achieve early molecular responses are more likely to achieve durable cytogenetic responses and are less likely to experience disease progression. Rising BCR-ABL transcript levels also indicate loss of response, often as a consequence of developing BCR-ABL mutations. However, some studies have suggested that patients who achieve complete cytogenetic disease remission may not derive an additional prognostic benefit from achieving a major molecular response. Practical issues also exist for molecular monitoring with respect to restricted access and variability in methodologies and data reporting. Although molecular monitoring has a clear role in assessing residual disease and determining the risk of disease progression in patients with CML, the importance of cytogenetic monitoring should not be ignored., ((c) 2008 American Cancer Society.)

Imatinib has dramatically altered the natural history of chronic myelogenous leukemia (CML), with the majority of patients now experiencing long-term remission and improved survival. However, in addition to the well-described phenomenon of resistance to imatinib, typically due to point mutations, uncommon consequences (eg, the development of Philadelphia chromosome-negative clones) may infrequently occur. We report 2 cases of sudden BCR/ABL1+ blast crisis in patients with CML who had achieved complete hematologic remission with imatinib therapy but were obligated to discontinue therapy owing to pancytopenia. These sudden blast crises were unusual at 3 levels: first, they were of precursor T lymphoblastic lineage; second, they had a primary extranodal presentation without overt bone marrow involvement; and third, they developed after recent cessation of imatinib. These observations suggest that the occurrence of 2 such rare cases in a single institution within a 1-year time frame may reflect another unusual consequence of imatinib therapy.

Repetitive elements are heavily methylated in normal tissues, but hypomethylated in malignant tissues, driving the global genomic hypomethylation found in cancer. This hypomethylation results in chromosomal instability, a well-characterized feature of the advanced phases of chronic myeloid leukemia (CML). We investigated methylation changes of DNA repetitive elements (LINE1, Alu, Satellite-alpha and Satellite-2) during the progression of CML from chronic phase (CP) to blast crisis (BC). CP-CML samples were significantly more hypomethylated for all repetitive sequences compared with normal samples. Furthermore, a more profound level of hypomethylation was observed among BC samples compared with CP samples. Our data suggest that repetitive DNA hypomethylation are closely associated with CML progression.

Chronic myeloid leukemia (CML) is characterized by the formation of the Philadelphia chromosome and oncogenic signaling by the resulting Bcr-Abl fusion protein. Understanding the molecular basis of CML has led to the development of highly effective targeted therapies that block Bcr-Abl tyrosine kinase activity. Imatinib, the current first-line therapy for CML, induces durable treatment responses in most patients. However, patients may develop imatinib resistance, which is often due to BCR-ABL mutations. With the availability of second generation tyrosine kinase inhibitors, an effective therapeutic option other than stem cell transplantation is available following imatinib failure. Randomized trial data suggest that dasatinib treatment is superior to imatinib dose escalation in patients with imatinib resistance. Nilotinib, a recently approved analogue of imatinib, has also demonstrated encouraging treatment responses in patients with imatinib-resistant CML. Other agents (including bosutinib and INNO-406) are in clinical development. With the potential availability of multiple treatment options for patients with CML, it may be possible to tailor treatment according to individual patient or disease characteristics, for example, BCR-ABL mutations. Future CML treatment may involve combination strategies. Overall, targeted agents have significantly improved the prognosis of patients diagnosed with CML.

Purpose: Chronic myeloid leukemia (CML), a hematopoietic stem cell cancer representing 15-20% of adult leukemias, is discussed. Epidemiology, staging biology, and monitoring techniques are reviewed., Summary: CML is a myeloproliferative disorder that affects all lineages of hematopoiesis. Final confirmation of CML comes with detection of the Philadelphia Chromosome (Ph) or BCR-ABL transcripts. The disease presents in one of three phases: chronic phase, accelerated phase, or blast crisis. Progression from chronic phase to accelerated phase usually involves the accumulation of additional cytogenetic aberrations and the arising of resistance to therapy. Although at one point mortality associated with CML was high, new kinase inhibitor therapies have markedly extended the life-span of these patients. These inhibitors were derived through the initial observation of the association of the Ph with CML and the eventual identification of the BCR-ABL oncogene which arises from this translocation. Analysis of the mechanism by which BCR-ABL transforms cells identified this protein as a tyrosine kinase and led to the targeting of this activity. The majority of patients present in chronic phase, which is where these kinase inhibitors have their greatest efficacy. Monitoring of disease progression is of critical importance as the prognosis drops significantly for patients with advanced disease. Blood counts, cytogenetics, and polymerase chain reaction (PCR) are currently used to assess disease. Blood counts are inexpensive but lack sensitivity. Cytogenetic karyotyping while requiring specialized training provides evidence of clonal evolution. Quantitative PCR is capable of tremendous sensitivity making it well suited for assessing response to therapy and the early detection of therapy failures., Conclusion: Our understanding of BCR-ABL has allowed the development of therapies, which may keep patients with CML in chronic phase indefinitely. This has created a situation in which patient monitoring is essential for detecting changes in the status of CML. The tests described here provide a comprehensive assessment of disease status allowing for effective patient management.

Purpose: In the first years of imatinib treatment, BCR-ABL remained detectable in all but a small minority of patients with chronic myeloid leukemia. We determined whether BCR-ABL continues to decline with longer imatinib exposure and the incidence and consequence of undetectable BCR-ABL., Experimental Design: BCR-ABL levels were measured in a subset of 53 imatinib-treated IRIS trial patients for up to 7 years (29 first-line, 24 second-line). Levels were deemed undetectable using strict PCR sensitivity criteria., Results: By 18 months, the majority achieved a 3-log reduction [major molecular response (MMR)]. BCR-ABL continued to decline but at a slower rate (median time to 4-log reduction and undetectable BCR-ABL of 45 and 66 months for first-line). The probability of undetectable BCR-ABL increased considerably from 36 to 81 months of first-line imatinib {7% [95% confidence interval (95% CI), 0-17%] versus 52% (95% CI, 32-72%)}. Undetectable BCR-ABL was achieved in 18 of 53 patients and none of these 18 lost MMR after a median follow-up of 33 months. Conversely, MMR was lost in 6 of 22 (27%) patients with sustained detectable BCR-ABL and was associated with BCR-ABL mutations in 3 of 6. Loss of MMR was recently defined as suboptimal imatinib response. There was no difference in the probability of achieving molecular responses between first- and second-line patients but first-line had a significantly higher probability of maintaining MMR [P = 0.03; 96% (95% CI, 88-100%) versus 71% (95% CI, 48-93%)]., Conclusions: With prolonged therapy, BCR-ABL continued to decline in most patients and undetectable BCR-ABL was no longer a rare event. Loss of MMR was only observed in patients with sustained detectable BCR-ABL.

Objective: To analyze and evaluate the clinical efficacy and safety of imatinib mesylate (IM) as a tyrosine kinase inhibitor on Ph-positive or BCR/ABL positive chronic myelogenous leukemia (CML)., Methods: 120 patients diagnosed as CML with positive Ph chromosome were treated with IM 400 mg/d for CML in chronic phase (CP) (n = 90) or 600 mg/d for CML in accelerated or blastic phase (AP or BP) (n = 30) once daily. Hematological, cytogenetic and molecular effects of IM on the disease process of these patients were evaluated with blood and marrow cells morphology examination, G-band conventional cytogenetics analysis for Ph chromosome and PCR assay for BCR/ABL gene. The treatment efficacy and safety were retrospectively studied., Results: (1) In CML-CP patients, after a follow-up of 9 ( range 3-42) months, cumulative complete hematological response (CHR), complete cytogenetic response (CCyR) and complete molecular response (CMR) rates were 73.3%, 66.7% and 54.4%, which was not influenced by prior treatment of interferon. CMR was better when time from diagnosis to treatment with IM was < or = 6 months (P < 0.05). The effect was not related with sex or age (P < 0.05). It is significant that the time to first CHR and time to first CCyR were related with the time to first CCyR and the time to first negative BCR/ ABL, respectively (both P < 0.05), while there was no relation between the time to first CHR and the time to first negative BCR/ABL (P > 0.05). (2) CHR, CCyR and CMR rates of the patients with progressive course (AP and BP) were 43.3%, 25.9% and 25.0%, respectively. The total mortality rate was 30.0%. (3) The mortality rate of the patients with age < or = 25 was higher than those >25 (P < 0.05). (4) Grade 3 leukocytopenia occurred in 16.0% of the patients and grade 3 thrombocytopenia in 18.0% of the patients and they 12 (5-20) weeks and 9 (3-16) weeks after the treatment, respectively. Nonhematological toxicities were common and tolerable., Conclusion: IM can lead to considerable hematological, cytogenetic and molecular response rates in CML, especially CML-CP patients, with minor tolerable side effects.

The development of chromosomal abnormalities (CAs) in the Philadelphia chromosome (Ph)-negative metaphases during imatinib (IM) therapy in patients with newly diagnosed chronic myecloid leukemia (CML) has been reported only anecdotally. We assessed the frequency and significance of this phenomenon among 258 patients with newly diagnosed CML in chronic phase receiving IM. After a median follow-up of 37 months, 21 (9%) patients developed 23 CAs in Ph-negative cells; excluding -Y, this incidence was 5%. Sixteen (70%) of all CAs were observed in 2 or more metaphases. The median time from start of IM to the appearance of CAs was 18 months. The most common CAs were -Y and + 8 in 9 and 3 patients, respectively. CAs were less frequent in young patients (P = .02) and those treated with high-dose IM (P = .03). In all but 3 patients, CAs were transient and disappeared after a median of 5 months. One patient developed acute myeloid leukemia (associated with - 7). At last follow-up, 3 patients died from transplantation-related complications, myocardial infarction, and progressive disease and 2 lost cytogenetic response. CAs occur in Ph-negative cells in a small percentage of patients with newly diagnosed CML treated with IM. In rare instances, these could reflect the emergence of a new malignant clone.

Background: In Philadelphia-negative chronic myeloproliferative disorders (CMPD), increased proliferation with effective maturation of the myeloid lineage is present, while peripheral leukocytosis, thrombocytosis or elevated red blood cell mass are found. This group of disorders includes polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF). Furthermore, cases that cannot be clearly defined are regarded as unclassified CMPD. In Philadelphia-negative CMPD, recurrent cytogenetic abnormalities occur, but no specific abnormality has been defined to date. Chromosomal abnormalities detected in a neoplastic disease as a sole anomaly are of major importance, possibly constituting primary changes implicated in the initiation or progression of the neoplastic process. The aim of this study was to investigate the frequency and the type of single chromosomal changes in Philadelphia-negative CMPD patients., Materials and Methods: By conventional cytogenetics, 245 Philadelphia-negative CMPD cases at diagnosis were investigated for the frequency and the type of single chromosomal aberrations., Results: Seventeen patients presented single chromosomal changes. These aberrations were, according to frequency, +8 (in 3 PV cases, 2 IMF and 2 unclassified myeloproliferative diseases), +13 in 3 cases (IMF, ET and unclassified myeloproliferative disease), monosomy 10 in 2 PV cases, monosomy 14 in one ET patient, +3, -4 and del(11)(q13) in 1 unclassified myeloproliferative disease each and monosomy 7 in 1 IMF case., Conclusion: It is unclear whether these abnormalities found at the time of diagnosis play a role in CMPD. However, since an isolated chromosomal abnormality may be implicated in the initiation of the neoplastic process, the documentation of more cases of CMPD with single abnormalities at the time of diagnosis would facilitate the identification of candidate genes involved in the neoplastic process.

Objective: To investigate the change of Philadelphia chromosome-positive clone with secondary chromosomal aberrations after imatinib mesylate (IM) treatment in patients with chronic myeloid leukemia (CML) and its relation with prognosis., Methods: 37 cases of CML in accelerated phase and blastic phase were collected and chromosome specimens of bone marrow cells were prepared by with 24-hour culture. G-banding technique was used for karyotyping., Results: The major secondary chromosomal aberrations were double Ph, +8, and i (17q); the minor ones were -Y, chromosome 17 abnormalities other than i (17q) and inv (3q). The percentage of Philadelphia chromosome-positive clone with secondary chromosomal aberrations showed the following 4 types of change; amplification, no change, decrease and complete remission after treatment with IM. 2 of the 24 cases in CML in accelerated phase gained complete cytogenetic response (CCyR) and 2 of the 13 in blastic phase did so. The groups with amplification and no change showed significantly shorter overall survival and progression free survival than the groups with decrease and complete remission., Conclusion: The percentage of Philadelphia chromosome-positive clone with secondary chromosomal aberrations may drop in some CML patients after IM treatment and the patients may gain CCyR with accompanied prolonged survival.

Microarray-based gene expression analysis was performed on diagnostic chronic phase CML patient samples prior to interferon treatment. Fifteen patient samples corresponding to six cytogenetic responders and nine non-responders were included. Genes differentially expressed between responder and non-responder patients were listed and a subsequent leave-one-out cross validation (LOOV) procedure showed that the top 20 genes allowed the highest prediction accuracy. The relevant genes were quantified by real-time PCR that supported the microarray results. We conclude that it might be possible to use gene expression analysis to predict future response to interferon in CML diagnostic samples.

Chronic myeloid leukemia (CML) was the first human malignancy to be associated with a single genetic abnormality, characterized by a reciprocal translocation involving chromosomes 9 and 22 (the Philadelphia chromosome). The fusion gene that results (BCR-ABL) produces a constitutively activated tyrosine kinase that exists in different isoforms depending on BCR break-points. Imatinib mesylate is a highly selective inhibitor of this kinase, producing normal blood-counts in 98% of patients in chronic phase CML and disappearance of the Philadelphia chromosome in 86%. However, 17% of patients in the chronic phase will either relapse or develop resistance resulting mainly from one or more point mutations affecting at least 30 amino acids within the Abl kinase protein. This review focuses on the relevant biology of CML, imatinib mesylate resistance mechanisms, and the current status of the next generation of Bcr-Abl inhibitors.

In this study, we provide a molecular signature of highly enriched CD34+ cells from bone marrow of untreated patients with chronic myelogenous leukemia (CML) in chronic phase in comparison with normal CD34+ cells using microarrays covering 8746 genes. Expression data reflected several BCR-ABL-induced effects in primary CML progenitors, such as transcriptional activation of the classical mitogen-activated protein kinase pathway and the phosphoinositide-3 kinase/AKT pathway as well as downregulation of the proapoptotic gene IRF8. Moreover, novel transcriptional changes in comparison with normal CD34+ cells were identified. These include upregulation of genes involved in the transforming growth factorbeta pathway, fetal hemoglobin genes, leptin receptor, sorcin, tissue inhibitor of metalloproteinase 1, the neuroepithelial cell transforming gene 1 and downregulation of selenoprotein P. Additionally, genes associated with early hematopoietic stem cells (HSC) and leukemogenesis such as HoxA9 and MEIS1 were transcriptionally activated. Differential expression of differentiation-associated genes suggested an altered composition of the CD34+ cell population in CML. This was confirmed by subset analyses of chronic phase CML CD34+ cells showing an increase of the proportion of megakaryocyte-erythroid progenitors, whereas the proportion of HSC and granulocyte-macrophage progenitors was decreased in CML. In conclusion, our results give novel insights into the biology of CML and could provide the basis for identification of new therapeutic targets.

A prospective randomized phase III study was performed to evaluate whether intensified cytarabine would induce a higher response rate and longer event-free interval as compared to low-dose cytarabine in chronic myeloid leukemia (CML). One hundred and eighteen patients with CML in early chronic phase entered the study. Twenty-eight out of 32 patients assigned to group A received two cycles of a combination of intensified cytarabine and idarubicin followed by interferon alfa (IFN-alpha) maintenance, 28 patients in group B received standard treatment by a combination of low-dose cytarabine and IFN-alpha. Forty-nine patients with a human leukocyte antigen-identical sibling donor proceeded to allogeneic stem cell transplantation (allo-SCT) and nine patients were excluded from the analysis. Hematological response was observed in 97% of the patients in group A vs 86% of the patients in group B during the first year of treatment. In group A, 16 patients (50%) achieved a major cytogenetic response, which compared to seven patients (25%) with a major cytogenetic response in group B. With a median follow-up of 58 months (range 34-76), event-free survival was not significantly different between arms A and B. The estimated 5-year survival rate was 56% in the intensified arm and 77% in the low-dose arm (P = 0.05). Recipients of allo-SCT showed a 5-year estimated survival rate of 55%. Although intensified cytarabine induced a higher initial percentage of major and complete cytogenetic responses, responses were not sustained by IFN-alpha maintenance therapy.

FLT3 gene mutations, either internal tandem duplication (ITD) or D835 point mutations, have been studied extensively in acute myeloid leukemia and myelodysplastic syndrome (MDS). Little is known about FLT3 mutations in chronic myeloproliferative diseases (CMPDs) or their relationship with V617F JAK2 mutations. We analyzed bone marrow samples from 142 patients with Philadelphia (Ph) chromosome- CMPD or CMPD/MDS and from 119 patients with Ph+ chronic myeloid leukemia (CML) using a multiplex polymerase chain reaction assay. FLT3 mutations, 11 ITD and 2 D835, were detected in 13 (9.2%) patients with CMPD or CMPD/MDS, 7 in blast phase and 6 in chronic phase. Analyses for JAK2 mutations in 11 of 13 cases were all negative. By contrast, no FLT3 mutations were detected in CML, including 108 chronic and 11 blast phase cases. FLT3 mutations occur in approximately 10% of CMPD and CMPD/MDS but are not observed in JAK2+ CMPD or in CML.

Despite recent success in the treatment of early-stage disease, blastic phase (BP) of chronic myeloid leukemia (CML) that is characterized by rapid expansion of therapy-refractory and differentiation-arrested blasts, remains a therapeutic challenge. The development of resistance upon continuous administration of imatinib mesylate is associated with poor prognosis pointing to the need for alternative therapeutic strategies and a better understanding of the molecular mechanisms underlying disease progression. To identify transcriptional signatures that may explain pathological characteristics and aggressive behavior of BP blasts, we performed comparative gene expression profiling on CD34+ Ph+ cells purified from patients with untreated newly diagnosed chronic phase CML (CP, n=11) and from patients in BP (n=9) using Affymetrix oligonucleotide arrays. Supervised microarray data analysis revealed 114 differentially expressed genes (P<10(-4)), 34 genes displaying more than two-fold transcriptional changes when comparing CP and BP groups. While 24 of these genes were downregulated, 10 genes, especially suppressor of cytokine signalling 2 (SOCS2), CAMPATH-1 antigen (CD52), and four human leukocyte antigen-related genes were strongly overexpressed in BP. Expression of selected genes was validated by real-time-polymerase chain reaction and flow cytometry. Our data suggest the existence of a common gene expression profile of CML-BP and provide new insight into the molecular phenotype of blasts associated with disease progression and high malignancy.

Aberrant genome-wide hypomethylation is thought to be related to tumorigenesis by promoting genomic instability. Since DNA methylation is considered an important mechanism for the silencing of retroelements, hypomethylation in human tumors may lead to their reactivation. However, the role of DNA hypomethylation in chronic myeloid leukemia (CML) remains to be elucidated. In this study, the methylation status of the LINE-1 (L1) retrotransposon promoter was analysed in CML samples from the chronic-phase (CP, n=140) and the blast crisis (BC, n=47). L1 hypomethylation was significantly more frequent in BC (74.5%) than in CP (38%) (P<0.0001). Furthermore, L1 hypomethylation led to activation of both ORF1 sense transcription (P<0.0001) and c-MET gene antisense transcription (P<0.0001), and was significantly associated with high levels of BCR-ABL (P=0.02) and DNMT3b4 (P=0.001) transcripts. Interestingly, in CP-CML, extensive L1 hypomethylation was associated with poorer prognosis in terms of cytogenetic response to interferon (P=0.004) or imatinib (P=0.034) and progression-free survival (P=0.005). The above results strongly suggest that activation of both sense and antisense transcriptions by aberrant promoter hypomethylation of the L1 elements plays a role in the progression and clinical behavior of the CML., (Oncogene (2005) 24, 7213-7223. doi:10.1038/sj.onc.1208866; published online 19 September 2005.)

Purpose: Point mutations within the ABL kinase domain of the BCR-ABL gene have been associated with clinical resistance to imatinib mesylate in chronic myeloid leukemia (CML) patients. To shed further light on the frequency, distribution, and prognostic significance of ABL mutations, we retrospectively analyzed a homogeneous cohort of late chronic phase CML patients who showed primary cytogenetic resistance to imatinib., Patients and Methods: Using denaturing high-performance liquid chromatography (D-HPLC) and sequencing, we screened for ABL mutations in a total of 178 bone marrow and/or peripheral blood samples from 40 late chronic phase CML patients homogeneously treated with imatinib 400 mg/d, who did not reach a major cytogenetic response at 12 months., Results: Mutations were found in 19 of 40 patients (48%). Mutations were already detectable by D-HPLC at a median of 3 months from the onset of therapy. The presence of a missense mutation was significantly associated with a greater likelihood of subsequent progression to accelerated phase/blast crisis (P = .0002) and shorter survival (P = .001). Patients carrying mutations falling within the P-loop seemed to have a particularly poor outcome in terms of time to progression (P = .032) and survival (P = .045)., Conclusion: Our results show that, irrespective of the hematologic response, monitoring for emerging mutations in the first months of therapy may play a role in detecting patients with worse prognosis, for whom a revision of the therapeutic strategy should be considered.

We report a 59-year-old man with chronic myelogenous leukemia (CML) in chronic phase who presented with a large abdominal tumor. Biopsy revealed proliferation of granulocytic-, erythroid-, and megakaryocytic-lineage cells in a retroperitoneal lymph node. The BCR/ABL fusion gene was detected on a paraffin-embedded tissue section of the lymph node by double-color fluorescence in situ hybridization, indicating an extramedullary hematopoietic tumor of CML origin. This patient has achieved a complete cytogenetic response for 19 months with imatinib mesylate (STI571; Gleevec), in association with the regression of the tumor. However, the development of an extramedullary tumor in chronic-phase CML generally indicates a poor prognosis, because it commonly consists of blast proliferation and is followed by blast crisis in the marrow within a few months. This case, therefore, points to the importance of histological examination of extramedullary tumors in CML for evaluation of disease status and for therapeutic decisions., (Copyright 2004 Wiley-Liss, Inc.)

Here we describe how we detected the BCR/ABL fusion gene on the short arm of der(9) combining classical GTG banding and Fluorescence In Situ Hybridization (FISH) in a case of chronic myeloid leukemia (CML). To our knowledge, variant translocations involving the short arm of chromosome 9, in literature, are almost rare in chronic myeloid leukemia. It is not clear if this complex genetic translocation represents clonal evolution or a unique, initial presentation variant of the Philadelphia chromosome (Ph).

Objective: To analyse the features of 8 cases of Bcr(+) thrombocytosis., Methods: The clinical and hematological features and therapeutic outcomes were studied retrospectively in 8 Bcr(+) thrombocytosis and compared with essential thrombocytosis (ET) and chronic myeloid leukemia-chronic phase thrombocytosis (CML-CP-T). BCR-ABL fusion gene was detected with PCR., Results: (1) Except for the presence of BCR-ABL fusion gene, there was no significant difference in clinical and hematological features and therapeutic outcomes between thrombocytosis with or without BCR-ABL. (2) The Bcr(+) thrombocytosis differed from CML-CP-T in the following aspects: female predominance, milder or no splenomegaly, peripheral leukocytes count < 40 x 10(9)/L, less or no basophilia and fewer immature granulocytes in peripheral blood, bone marrow granulocytic and/or megakaryocytic lineage hyperplasia, normal or increased neutrophil alkaline phosphatase score and less blastic transformation., Conclusion: Bcr(+) thrombocytosis may be considered as a new member of chronic myeloproliferative diseases, a variant of essential thrombocythemia.

Chronic myelogenous leukaemia (CML) cells show expression of BCL-X(L), an anti-apoptotic oncogene. This expression is induced by BCR-ABL protein kinase through activation of the signal transducer and activator of transcription-5 protein (STAT5). To date, however, the contribution of BCL-X(L) and STAT5 to the transforming phenotype in CML is still unclear. This study was aimed at defining the status of activated STAT5 and BCL-X(L) expression and their relation to BCR-ABL rearrangement in CML cells derived from patients at different clinical stages. Twenty-seven consecutive patients with CML were enrolled in the study. Peripheral blood mononuclear cells were lysed and subjected to immunoprecipitation and Western blotting to analyse phosphorylated STAT5. The p210 BCR-ABL rearrangements were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and BCL-X(L) expression by semi-quantitative RT-PCR. We found that increased transcription of BCL-X(L) gene was associated with phosphorylated STAT5 in the majority of blast crisis patients and in a few accelerated and chronic phase patients. Moreover, BCL-X(L) expression levels were found to be decreased in chronic phase, contrary to a marked increase in blast crisis. We found no difference in expression of BCL-X(L) and phosphorylated STAT5 when related with b3a2 and b2a2 BCR-ABL rearrangements. These results suggest that STAT5 activity and BCL-X(L) overexpression may reflect a stage of differentiation among CML phases, and this could contribute to BCR-ABL-dependent transformation.

Chronic myelogenous leukemia (CML) is a malignancy of the human hematopoietic stem cell (HSC) caused by the p210BCR/ABL oncoprotein. Although alternative splicing of pre-mRNA is a critical determinant of a cell's protein repertoire, it has not been associated with CML pathogenesis. We identified a BCR/ABL-dependent increase in expression of multiple genes involved in pre-mRNA splicing (eg SRPK1, RNA Helicase II/Gu, and hnRNPA2/B1) by subtractive hybridization of cDNA from p210BCR/ABL-eGFP vs eGFP-transduced umbilical cord blood CD34+ cells. beta1-integrin signaling is important to HSC maintenance and proliferation/differentiation, and is abnormal in CML. As an example of how changes in pre-mRNA processing might contribute to CML pathogenesis, we observed alternative splicing of a gene for a beta1-integrin-responsive nonreceptor tyrosine kinase (PYK2), resulting in increased expression of full-length Pyk2 in BCR/ABL-containing cells. Treatment of p210BCR/ABL-positive cells with the Abl-specific tyrosine kinase inhibitor STI571 reverted PYK2 splicing to a configuration more consistent with normal cells, and correlated with decreased expression of BCR/ABL-induced proteins involved in pre-mRNA processing. Whether altered PYK2 splicing contributes to CML pathogenesis remains undetermined; however, we propose that generic changes in pre-mRNA splicing as a result of p210BCR/ABL kinase activity may contribute to CML pathogenesis.

The new knowledge in molecular biology and pathophysiology of chronic myeloid leukemia enabled the development of imatinib mesylate (Glivec, formerly STI571). Imatinib potently inhibits several protein tyrosine kinases, including BCR-ABL, c-Kit, and PDGF receptor. Imatinib blocks the phosphorylation of downstream target proteins and interrupts the malignant transformation leading to the development of CML. Phase I and II studies demonstrated that imatinib is highly effective and well tolerated in all phase of CML. We got our experience with imatinib on more than two-year monitoring 34 patients within the Expanded Access Study CST1571 0113. Imatinib 400 mg/d was administered orally to 10 women and 24 men in median age of 53 years (22-70) who were hematologically (n = 9) or cytogenetically (n = 13) resistant, cytogenetically refractory (n = 3) or intolerant (n = 9) to interferon alpha. The median follow-up time was 97.5 weeks (23-115), the median time from CML diagnosis to the start of the study was 32.3 months (6-140.5). Complete hematologic response was achieved in 33 of 34 (97%) pts, total major cytogenetic response (complete plus major) in 21 of 33 (63%) pts. Cytogenetic relapse was observed in 2 of 33 pts (6%), cytogenetic progression in 4 (12%) pts. Non-hematologic toxicity was mild (grade 1 or 2) and no patient was excluded from the study due to it. Hematological toxicity grade 3 limited dose of imatinib in 26% of patients and probably caused lower rate of cytogenetic responses in heavy pretreated patients. Both quantitative RT-PCR methods (competitive RT-PCR and real-time RT-PCR Light-Cycler) were found useful to monitor patients with CML on imatinib therapy. Our results confirmed high efficacy and safety of imatinib in late-chronic phase CML patients failing prior interferon therapy. The lower incidence of hematological toxicity and higher rate of cytogenetic responses in patients treated with imatinib in early-chronic phase CML justify according to our opinion the recommendation to administer imatinib early after the diagnosis of CML in patients who are not indicated for allogeneic transplantation.

Objective: To compare the therapeutic effects of STI 571 in treating Philadelphia chromosome (Ph)-positive patients with chronic-phase and acceleration phase chronic myeloid leukemia (CML-CP and CML-AP, respectively)., Methods: A total of 19 CML patients with Ph chromosome and/or fluorescence in situ hybridization (FISH)-bcr/abl fusion gene positivity rates over 90% and a median age of 38 years were recruited in this study, 12 of whom had previously failed to respond to interferon-alpha. Five of the 19 patients were in accelerated phase and 14 in chronic phase, 9 of the latter patient group in early stage of CML-CP (within 1 year since diagnosis) and 5 in advanced stage (3-6 years since diagnosis). All the patients were given oral STI 571 at the dose of 300-500 mg/d for a median treatment course of 5 months, and the 5 patients with CML-AP also received homoharringtonine at dose of 1-2 mg/d for an average of 1.5 treatment cycles (7-14 d for a complete treatment cycle). The Ph chromosome and the FISH-bcr/abl were analysed again 3 months after the treatment., Results: STI 571 induced 100% complete hematological remission (CHR) and 79% major cytogenetic responses (MCR) in these patients. The complete cytogenetic remission (CCR) rates of CML-AP patients and CML-CP patients in advanced stage were lower than that of CML- CP patients in early stage (0% and 40% vs 88.9%)., Conclusion: STI 571 can achieve high rate of CHR and MCR in CML-CP patients, especially in those in early stage of the disease.

Background: Anecdotal cases of chromosomal abnormalities in Philadelphia chromosome (Ph)-negative metaphases have been reported in patients with chronic myelogenous leukemia (CML) in the chronic phase during treatment with interferon and, more recently, with imatinib. This phenomenon is different from true clonal evolution in that the additional cytogenetic abnormality occurs in Ph-negative cells., Methods: The authors analyzed their experience with 342 patients with CML in chronic phase treated with imatinib to investigate the frequency and significance of this event., Results: After a median follow-up of 30 months (range, 16-35 months), 21 patients (6%; 95% confidence interval, 0.04, 0.09) developed 25 chromosomal abnormalities in Ph-negative cells. Thirteen (54%) of these abnormalities were seen in 2 or more metaphases. The median time from the start of treatment with imatinib to the appearance of the abnormalities was 6 months (range, 3-22 months). The most common cytogenetic abnormality detected was trisomy 8 (33%). Twenty of 21 patients (95%) achieved a major (Ph < 35%) cytogenetic response (complete cytogenetic response in 13-62%). After a median follow-up of 22 months (range, 4-33 months), all 21 patients were alive, 20 of them in chronic phase and in complete hematologic response. None of the patients showed features of myelodysplasia., Conclusions: Cytogenetic abnormalities occur in Ph-negative cells in a fraction of patients with CML in chronic phase treated with imatinib. With a short follow-up, no clear clinical consequences can be identified., (Copyright 2003 American Cancer Society.)

Ph chromosome occurs in nearly all patients with CML, and eliminating Ph-positive clone is a major target in the treatment of CML. IFN-alpha is a well-known effective treatment in chronic phase CML. The cytogenetic response and the prognostic factors in 128 CML patients treated with IFN-alpha were retrospectively studied. IFN-alpha administered singly at a dose of 3 million U/day for 2 - 3 times a week or in combination with either hydroxyurea (Hu), busulfan (Bu), low dose Ara-C or harringtonine. Karyotyping was examined by G-banding before and after IFN-alpha-based treatment. The results showed that all patients achieved complete hematological remission. Cytogenetic response occurred in 36 of 118 patients with standard t (9;22) translocation; 3 of these 36 patients had a complete cytogenetic response (Ph = 0), 13 had major cytogenetic responses (Ph < 35%) and 20 had minimal response (Ph > 35%). The total cytogenetic effectiveness was 13.6% (16/118). Four of seven patients with complicated variant translocation also achieved cytogenetic response, 2 of them had a major cytogenetic response and 2 had minimal response. Factors influenced the prognosis associated with cytogenetic response included sex, patient status at diagnosis and IFN-alpha administered singly or in combination with other chemotherapeutic agents. IFN-alpha could not prevent the progression of CML. It is concluded that Ph(+)CML patients with both standard and variant translocation had major cytogenetic response to IFN-alpha treatment at a dose of 6 - 9 million U/week in single or combination with Hu/Bu, however, IFN-alpha treatment could not prevent disease progression. Long term survival was also observed in patients with variant translocation treated with IFN-alpha. Regular cytogenesis examination in CML patients is necessary during IFN-alpha therapy, which is useful to reflect curative effect and progression of the disease.

Aim: To evaluate efficacy and tolerance of glivek in chronic myeloid leukemia (CML) in patients who failed interferon-alpha (If-a) preparations., Material and Methods: 79 patients in a chronic phase of Ph + CML with hematological and cytogenetic resistance or intolerance of If-a. The response to glivec was assessed by achievement of a complete hematological remission and the cytogenetic effect (the degree of reduction of cell clone Ph+ in bone marrow). Tolerance and safety of the drug was studied by monthly standard clinicohematological tests., Results: Not only a hematological remission (92.4%), but also partial (46.8%) or complete (27.8%) elimination of BCR-ABL +/- cells were achieved after 12 months of the treatment. Glivec was well tolerated. Hematological toxicity primarily as neutropenia and thrombocytopenia were observed in 54.4 and 42% patients, respectively. Neutropenia of the third degree which made impossible to continue the treatment was observed in 29.1% patients; throbocytopenia of the third degree was registered in 16.5% patients. Among most frequent non-hematological side effects there were moderate edema, nausea, leg muscle convulsions, weight gain, arthralgias, skin eruption. All the complications were transient, were managed in all cases with only a short-time discontinuation of glivec therapy., Conclusion: High activity of glivec at early stages of CML allows using this drug as a first-line therapy in patients with CML.

We have analysed the outcome of 581 autologous stem cell transplants (SCT) for chronic myeloid leukaemia (CML) in first chronic phase reported to the European Group for Blood and Marrow Transplantation between 1983 and 1998. Out off 207 patients evaluable for cytogenetics within 6 months of SCT, 36 patients (17%) were in complete cytogenetic remission (CCR), 34 (16%) in major remission (MCR), 74 (36%) in minor remission (mCR) and 63 (31%) had no cytogenetic response (NR). Interferon (IFN) was given post SCT to 267 patients. Results of the cytogenetic analysis within 1-2 years from SCT were available for 117 patients, the majority of whom (n = 101) received IFN post SCT: 17 (15%) were in CCR, 18 (15%) in MCR, 24 (20%) in mCR and 58 (50%) NR. The median survival in this series was 96 months (71-125) from SCT. There was no difference in survival according to cytogenetic status pre- and immediately post SCT. However, patients in CCR or MCR at 1-2 years post SCT had a 10-year survival of 66% compared with 36% for patients in mCR or NR (P = 0.003). The 5-year survival for patients receiving IFN post SCT was 72% compared with 61% for patients not treated with IFN (P = 0.01). Out of 155 patients refractory to IFN pre SCT, 70% achieved a cytogenetic response post SCT, which was complete or major in 31%. IFN refractory patients who sustained a CCR or MCR for 1-2 years after SCT had an excellent outcome.

Chronic myelogenous leukemia (CML) is characterized by the Philadelphia (Ph) chromosome and bcr/abl gene rearrangement which occurs in pluripotent hematopoietic progenitor cells expressing the c-kit receptor tyrosine kinase (KIT). To elucidate the biological properties of KIT in CML leukemogenesis, we performed analysis of alterations of the c-kit gene and functional analysis of altered KIT proteins. Gene alterations in the c-kit juxtamembrane domain of 80 CML cases were analyzed by reverse transcriptase and polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP). One case had an abnormality at codon 564 (AAT --> AAG, Asn --> Lys), and six cases had the same base abnormality at codon 541 (ATG --> CTG, Met --> Leu) in the juxtamembrane domain. Because the change from Met to Leu at codon 541 was a conservative one which was also observed in the normal population and normal tissues of CML patients, it probably represents a polymorphic variation. Although samples of hair roots and leukemic cells from the chronic phase of one CML patient showed no abnormality, an abnormality at codon 541 (ATG --> CTG, Met --> Leu) was found only at blastic crisis (BC) of this case. In the case with the abnormality at codon 564, the mutation was detected only in a sample of leukemic cells collected at BC. To examine the biological consequence and biological significance of these abnormalities, murine KIT(L540) and KIT(K563) expression vectors were introduced into interleukin-3 (IL-3)-dependent murine Ba/F3 cells to study their state of tyrosine phosphorylation and their growth rate. Ba/F3 cells expressing KIT(WT), KIT(L540) and KIT(K563) showed dose-dependent tyrosine phosphorylation after treatment with increasing concentrations of recombinant mouse stem cell factor (rmSCF). The cells expressing KIT(L540) and KIT(K563) were found to have greater tyrosine phosphorylation than cells expressing KIT(WT) at 0.1 and 1.0 ng/ml of rmSCF. The Ba/F3 cells expressing KIT(K563) proliferated in response to 0.1 and 1.0 ng/ml of rmSCF as well as IL-3. The Ba/F3 cells expressing KIT(L540)showed a relatively higher proliferative response to 0.1 ng/ml of rmSCF than the response of cells expressing KIT(WT). These mutations and in vitro functional analyses raise the possibility that the KIT abnormalities influence the white blood cell counts (P < 0.05) and survival (P < 0.04) of CML patients.

Background: Many cancers display alterations in methylation patterns of CpG islands--stretches of DNA rich in CpG dinucleotides often associated with gene promoters that are involved in initiation of gene transcription. This methylation may perturb expression of genes critical to the regulation of cell proliferation. Aberrant methylation is not limited to a few genes or to promoter regions but has been found on a genome-wide scale in a variety of neoplasias, including colorectal cancer and acute myelogenous leukemia. Our goal was to characterize, in a quantitative manner, the profiles of abnormally methylated genes that may be specific for different cancers., Methods: Using a quantitative assay, methylation-sensitive single nucleotide primer extension (MS-SNuPE), we have analyzed the methylation levels of promoter and exonic (coding region) CpG islands of two cyclin-dependent kinase inhibitors [p15(INK4B) and p16(INK4A)] and the PAX6 gene, which encodes a transcriptional factor involved in neuronal proliferation, in DNA samples taken from patients with chronic myelogenous leukemia, acute myelogenous leukemia, myelodysplastic syndrome, and colorectal cancer., Results: De novo methylation of all three exonic loci in tumors--relative to baseline levels found in nontumor tissue or blood--was observed in hematologic neoplasias and in solid tumors as well as in normal colonic tissue. However, methylation of promoter regions was more limited. Moreover, two different patterns of promoter methylation distinguished the leukemias from colorectal cancer: p15 promoter hypermethylation was found only in the leukemias, and p16 promoter hypermethylation occurred only in colon tumors. However, we did not address this issue prospectively; therefore, such an observation is only hypothesis generating., Conclusions: The methylation patterns that we observed suggest that exonic CpG islands are more susceptible to de novo methylation than promoter islands and that methylation may be seeded in exonic regions, from which it can spread to other islands, including promoter regions. Subsequent selection of cells with a growth advantage conferred by spread of methylation into and inactivation of a particular promoter might then contribute to the genesis of a specific type of cancer.

A woman with Ph-positive chronic myeloid leukaemia (CML) with an atypical e1a3 BCR-ABL hybrid gene is described. To our knowledge, this is the first report of this transcript type as a unique naturally occurring BCR-ABL fusion in a CML patient. This case was characterized by a low leucocyte count and a very indolent course without treatment. Because the deletion of ABL exon 2 sequences results in deletion of an essential part of the ABL SH3 domain, our case suggests that this ABL SH3 domain is not absolutely necessary for efficient induction of a myeloproliferative disease in the context of BCR-ABL/p190.

Multistep carcinogenesis is exemplified by chronic myeloid leukemia with clinical manifestation consisting of a chronic phase and blast crisis. Pathological generation of BCR-ABL (breakpoint cluster region-Abelson) results in growth promotion, differentiation, resistance to apoptosis, and defect in DNA repair in targeted blood cells. Domains in BCR and ABL sequences work in concert to elicit a variety of leukemogenic signals including Ras, STAT5 (signal transducer and activator of transcription-5), Myc, cyclin D1, P13 (phosphatidylinositol 3-kinase), RIN1 (Ras interaction/interference), and activation of actin cytoskeleton. However, the mechanism of differentiation of transformed cells is poorly understood. A mutator phenotype of BCR-ABL could explain the transformation to blast crisis. The aim of this review is to integrate molecular and biological information on BCR, ABL, and BCR-ABL and to focus on how signaling from those molecules mirrors the biological phenotypes of chronic myeloid leukemia.

Between October 1993 and March 1999, 29 patients with CML who were ineligible for allogeneic BMT underwent PBSC harvest using idarubicin, cytarabine and G-CSF. In 9/29 (31%) patients all collected stem cells were Ph-negative, and 15/29 patients' (52%) collections were substantially (>95%) Ph-negative. The proportion of patients from whom Ph-negative stem cells were obtained was similar between patients who had, or had not, received prior alphaIFN. Fifteen patients in chronic phase (median age 45) proceeded to PBSCT following busulphan 16 mg/m2 and cyclophosphamide 120 mg/m2. Nine of the 13 patients who had failed to respond to prior alphaIFN proceeded to stem cell transplantation as soon as was feasible and six of the newly diagnosed patients were transplanted after failing to achieve a cytogenetic response after a minimum of 12 months on alphaIFN following progenitor cell harvest. The median number of days to neutrophils >0.5 and platelet >50 was 18 (range 13-69) and 28 (range 13-234), respectively. There was no procedure-related mortality. At median follow-up of 2.3 years post autograft 10 of 15 patients remain alive and in chronic phase. Overall survival for all 27 patients at 5 years after initial diagnosis is 70% and median survival from diagnosis 7.3 years. Survival for alphaIFN non-responders who were transplanted is 74% at 5 years from diagnosis and 75% at 3 years from transplant. Cytogenetic analysis performed 3 months post transplant demonstrated one patient with a complete cytogenetic response, seven with a partial response and three with no response. Six patients remain partially Ph-negative, with one major CR. Survival for all patients in the protocol is favourable compared with conventional therapy and is particularly encouraging following PBSCT for alphaIFN non-responsive patients. Patients not responding to alphaIFN can be induced into Ph-negativity with PBSCT but this may not always be sustainable. There seems to be no obvious disadvantage in harvesting stem cells after prior exposure to alphaIFN, providing an adequate alphaIFN-free rest period is used.

In the last decade, improvements in both non-transplant and transplant therapy have extended the lives of patients with CML, particularly those in chronic phase. The future will probably bring a greater understanding of molecular leukaemogenesis and options for treating CML. Non-transplant therapies in development include novel agents and combination therapy. Transplant strategies seek to decrease regimen-related toxicity and directly manipulate the immune system to eradicate disease. Clinical and laboratory science seems poised to add novel therapies to the armamentarium against CML. It is exciting to contemplate what reviews of CML written 10 years from now will discuss.

In chronic myeloid leukemia, accurate determination of Ph(-) Hemopoietic stem cells (HSC) in peripheral blood (PB), bone marrow (BM) and leukapheresis products is important for the selection of patients for whom mobilization, collection, and autografting of Ph(-) HSC are envisaged. To this effect, the BCR/ABL fusion was assessed at the single cell level in 25 sets of PB and BM samples using dual-color I-FISH in immunophenotyped CD34(+) cells and RT-PCR of individual CFU-GM colonies. In 15 cases found to be 100% Ph(+), the respective BCR/ABL gene was absent in 30% of CD34(+) cells, while the respective transcripts could not be identified in 17% of CFU-GM. The mean percentage of BCR/ABL(-) CD34(+) cells and CFU-GM cells was higher (38% and 29%, respectively) in untreated patients than in treated patients (24% and 7%, respectively). In eight cases with cytogenetic response (CgR), the percentage of Ph(-) metaphases correlated with the level of BCR/ABL(-) colonies in BM and PB and with the proportion of BCR/ABL(-) CD34(+) cells in the BM. Immunophenotyping and FISH was fast, easy, always informative, and quantitative for the BCR/ABL(-) CD34(+) cells. Our results show that (a) at early diagnosis a high frequency of BCR/ABL(-) HSC circulate in the PB and that Ph(-) hematopoiesis is not completely suppressed; (b) although normal clonogenic cells decline rapidly within a few months after diagnosis, appreciable numbers of normal CD34(+) cells survive in chronic phase, especially in patients with CgR.

The use of the real-time reverse-transcription polymerase-chain reaction (RT-PCR) method to quantify BCR-ABL transcripts before and after allogeneic transplant was prospectively studied in 65 patients with chronic myeloid leukemia (CML). The expression of the BCR-ABL transcript was determined and normalized using the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) housekeeping gene product as an endogenous reference. In the single step real-time PCR assay, tenfold serial dilutions of cDNA of the K5652 cell line remained positive down to 100 pg cDNA only. However, molecular relapses of CML after transplant were only safely detectable when a nested real-time PCR assay was performed, which was able to detect 1-10 pg cDNA from a tenfold serial dilution. The median normalized BCR-ABL transcript level was measured as 0.004% in 17 patients with a molecular relapse, 0.4% in 7 patients with a cytogenetic relapse, 2.6% in 36 patients with a stable phase of CML, and 36% in 5 patients with a relapse in a blast crisis. The analyzed median normalized amount of BCR-ABL transcript differed significantly (P<0.001) between the various disease stages. In ten CML patients with relapse, the real-time PCR method was used to monitor the response of various immunotherapies as donor leukocyte infusions, withdrawal of immunosuppression, or interferon-alpha application. The results of the quantitative evaluation of BCR-ABL transcripts reflected very well the clinical effect of the different applied immunotherapies. The new real-time PCR method seems to be a suitable technique for the early detection of relapse after allogeneic transplant in patients with the BCR-ABL transcript. Its ability to distinguish between molecular and cytogenetic relapse (P<0.001) allows early therapeutic decisions.

Treatment with interferon-alpha (IFNalpha) prolongs survival in chronic myeloid leukemia (CML). Additionally, cytarabine (AraC) can reduce the number of Ph + metaphases. Fortythree previously untreated patients with CML in chronic phase were randomly assigned to receive either. IFNalpha 2b (5 MU sqm/daily) or IFNalpha 2b in the same dosages plus monthly courses of low-dose AraC. The aim were complete hematologic remission at 6 months and cytogenetic response at 12 months. A complete hematologic remission occurred in 60.4% patients with single IFNalpha 2b in 76.2% patients with combination therapy. A cytogenetic response was present in 13.9% (major in 2 patients) with IFN therapy and in 38.1% patients with combination therapy. Two of 21 patients treated with IFNalpha/AraC therapy achieved major (9.52%), 4 partial (19.04%) and 2 minor (9.52%) cytogenetic response. Major side effects were cytopenia (20.1%), flu-like syndromes (42.4%) and increase of hepatic transaminases (3.4%). The side effects were more significant in the group receiving combination therapy. Based on published data that show a survival advantage for patients who achieved any cytogenetic response, and high rate of cytogenetic response which we observed in our study we believe that IFN plus AraC regimen could be a front-line therapy for CML.

This report describes two cases of Philadelphia chromosome-negative (Ph(-)) non-Hodgkin's lymphomas (NHLs) recognized in patients with chronic phase Ph-positive (Ph(+)) chronic myelogenous leukemia (CML). Lymph node biopsy of patient 1 was initially diagnosed as diffuse large B cell non-Hodgkin's lymphoma (NHL, T cell rich variant), but at relapse showed immunoblastic features with a marked decrease of admixed lymphocyte components. Patient 2 presented with thickened parietal pleura which revealed a CD30-positive anaplastic large cell lymphoma showing null cell phenotype and genotype with abundant admixed neutrophils and lymphocytes. At the time of lymphoma diagnosis, the patients had CML for 33 and 10 months, respectively. DNA obtained from bone marrow cells at the time of lymphoma diagnosis showed BCR/ABL gene rearrangements by both Southern blot analysis and reverse transcription polymerase chain reaction (RT-PCR), but lacked both immunoglobulin and T cell receptor gene rearrangements. BCR gene rearrangement and BCR/ABL fusion gene were also identified in lymph node and pleural biopsies by Southern blot and RT-PCR analysis, respectively. However, both biopsy specimens also contained reactive lymphocytes and neutrophils, and no fusion signals between BCR and ABL genes were identified in the hyperdiploid lymphoma cells of either case by fluorescence in situ hybridization (FISH). These data suggest the lymphoma cells in both cases were not genetically associated with BCR/ABL. Therefore, these cases were not diagnosed as an extramedullary localized blast crisis in CML, but as Ph(-) NHLs. This represents the first definitive demonstration of peripheral B cell lymphoma occurring by a separate genetic pathway, lacking BCR/ABL, in patients with Ph(+) CML. A review of the literature identified two different subtypes of malignant lymphomas arising in patients with an antecedent or concurrent diagnosis of CML. The most common are T cell lymphomas displaying an immature thymic phenotype, while peripheral B cell lymphomas are more rare. Our study shows, however, that 'Ph(+) NHL' occurring in CML or acute lymphocytic leukemia (ALL) may represent an unrelated neoplasm, even if standard cytogenetic analysis reveals a Ph(+) chromosome, and that FISH is required to confirm whether a localized lymphoid neoplasm is either a true extramedullary localized blast crisis or genetically distinct neoplasm. Leukemia(2000) 14, 169-182.

Several groups have shown that Ph-progenitors reappear in LTC of CML bone marrow or PBMNC when the cell preparations were derived from newly diagnosed Ph-positive patients or after induction chemotherapy. We have tested the hypothesis whether LTC may further decrease CML progenitors if the cells to be cultured were from IFN-treated patients. In our experiments, PBMNC were cultured from 7 IFN- and 5 HU-treated patients in stable chronic phase of the disease, and from 9 patients at diagnosis. Progenitor cells in PBMNC were quantitatively analyzed before and after 35 days of LTC by combining the clonogenic assay in semisolid medium with dual-color interphase FISH for identification of the BCR/ABL status of colony-forming progenitor cells. A median of 22 colonies (range 7-88) before and 30 colonies (5-71) after LTC were analyzed per patient. Our results show that the number of BCR/ABL-positive CFC before and after LTC was approximately the same. This was independent of IFN or HU therapy. In the IFN group there were 58% (median) BCR/ABL-positive CFC before and 54% (median) after LTC of PBMNC. In the HU group, 80% of CFC were BCR/ABL-positive before and 85% after LTC. A complete elimination of BCR/ABL-positive cells was not achieved. We conclude that CML early progenitors in PBMNC of IFN-treated CML patients may survive LTC.