Different Phases Of Chronic Myeloid Leukemia Research Articles

Treg Cells, FoxP3 and TGF-β Expression and Significance in Chronic Myeloid Leukemia

To investigate the expression and significance of regulatory T cells (Tregs), FoxP3 and transforming growth factor-β (TGF-β) in different phase of chronic myeloid leukemia (CML). Peripheral blood of 73 CML patients in Department of Hematology, Heze Municipal Hospital from March 2018 to March 2021 were collected. According to patient's period in CML, they were divided into ND CML group (newly diagnosed), CP CML group (chronic period), and BP CML group (blast phase). The percentage of Tregs, expression level of FoxP3 mRNA and TGF-β were detected by flow cytometry, RT-qPCR, and ELISA, respecitively. The roles of above indices in clinical pathogenesis of patients with CML were analyzed. The proportion of Treg in the ND CML group was slightly higher than the CP CML group, but the difference was not statistically significant (P =0.695), while the BP CML group was significantly higher than the other two groups (P =0.008, P <0.001). The expression levels of FoxP3 mRNA in ND CML group, CP CML group and BP CML group were 11.61±2.21, 6.46±1.35 and 8.54±2.13, respectively. Significant difference in FoxP3 mRNA levels was observed among patients in different phases of CML (F =55.199, P <0.001). The expression levels of FoxP3 mRNA both in ND CML group and BP CML group were significantly higher than that in CP CML group (P <0.001), and the ND CML group was the highest (P <0.001). However, the expression levels of TGF-β in different phases of CML showed no statistical differences (H =0.634, P =0.728). The abnormal distribution of Treg subset in different phases of CML and the significant increase of the expression level of FoxP3 mRNA in the new onset and blast phase of CML suggest that Tregs may promote the occurrence and progression of CML through immune regulation.

Serum Vascular Endothelial Gowth Factor Correlates with Hasford Score in Chronic Myeloid Leukemia.

Introduction and Aim Increased angiogenesis in BM is one of the characteristics of chronic myeloid leukemia (CML) implicated in its progression. Vascular endothelial growth factor (VEGF) one of the most potent regulator of angiogenesis is increased in CML. The prognostic impact of serum VEGF in CML is largely unknown with sparse literature from India. So the present study aimed to measure serum VEGF levels in different phases of CML and to assess its prognostic significance using Hasford score. Methods Forty Ph + patients of CML were enrolled in the study. Complete clinical history and physical examination was done. Hemogram was done by Beckman Coulter LH 500. Peripheral smear (Wright's stain) was done by microscopy. Serum VEGF (plain vial) using ELISA was calculated. Statistical analysis was performed using SPSS software version 20. Results The mean serum VEGF levels were significantly higher in patients than in controls (p < 0.0001). The patients in accelerated/blast phase demonstrated significantly higher levels of serum VEGF (mean 151pg/mL) than those in the chronic phase (mean 90.87pg/mL) (p = 0.02). Serum VEGF levels showed a significant positive correlation with the overall Hasford prognostic score (p = 0.023). Conclusion Serum VEGF levels can serve as an independent prognostic marker in CML patients irrespective of phase of CML. Also, S. VEGF levels can be used to monitor patients on imatinib therapy and identify those who might benefit from antiangiogenesis therapy. However, larger studies are needed with a larger number of patients in different phases of CML to validate our findings and thus pave the way for future research.

Interleukin 6 and disease transformation in chronic myeloid leukemia: A Northeast Indian population study.

Interleukin 6 (IL6) has been suggested to be a valuable prognostic marker in chronic myeloid leukemia (CML). IL6 is a pleiotropic cytokine and plays an important role in immune response, hematopoiesis, and acute phase response. IL6 is regarded as a prominent target for clinical interventions. The aim of the present study was to investigate the serum levels of IL6 in CML to provide greater insight to their role in disease transformation in Indian patients. A total of 50 CML cases and 10 acute lymphocytic leukemia (ALL) cases along with 20 healthy controls were included in the study between 2015 and 2016. About 4 mL blood samples were collected from all cases in plain vial and serum was separated. Levels of IL6 were determined in all cases by enzyme-linked immunosorbent assay. The study suggests that both ALL and CML are associated with significantly elevated serum IL6 level than the healthy control group. Mean levels of serum IL6 are 223.4 ± 53.403 pg/mL in CML, 71.020 ± 29.549 pg/mL in ALL, and 5.360 ± 0.467 pg/mL in healthy control group. Serum IL6 correlated with different phases of CML. Mean IL6 levels are 50.93 ± 29.37 pg/mL in chronic phase (CP), 69.02 ± 22.60 pg/mL in accelerated phase (AP), and 652.77 ± 124.62 pg/mL in blast crisis (BC) phase of CML. In compared to CP and AP, in BC, IL-6 is significantly elevated ( P = 0.00 and 0.00, respectively); however, we did not find a significant difference in IL-6 serum levels between CP and AP ( P = 0.703). Study suggests that the detection of IL6 level in newly diagnosed patient can predict the severity of the disease. There might be association of level of IL6 with the disease transformation.

This Is a Title in Title Case: Prediction of CML Evolution By Telomere Length Analysis at the Single-Chromosome Level

Telomeresplay a vital role in DNA repair activities and protecting chromosomes from degradation[1]. Telomeres are shortened during each cell division because of the end replication problem. After several cell division, telomeres are shortened to a critical length (&lt; 3 kb), and eventually lead to overall genomic instability and triggering the DNA damage response[2-3], which is related to the cancerization of numerous cancers. The commonly used method to estimate telomere length isterminal restriction fragment (TRF) basedon southern blot, which requires thousands of cells and provides only a crude estimate of the average telomere length of all cells analyzed. However, it is believed that the frequency of critically short telomeres, rather than the mean telomere length, is a crucial factor for telomere dysfunction. Therefore, analysis of telomere length at the single-chromosome level is necessary to determine the frequency of critically short telomeres. Here, we describe the development of a high-throughput method for telomere length analysis at the single-chromosome level by using a laboratory-built high-sensitivity flow cytometer (HSFCM)[4] combined with targeted fluorescent peptide nucleic acid (PNA) probes. The unambiguous detection of the telomere signalsfrom a single chromosome was achieved via HSFCM analysis. The fluorescence intensity of single chromosome was converted to the probe number by a calibration curve, and was further transformed to the base pair number of the telomere. Five representative cell lines were analyzed to compare their telomere length and the ratio of critically short telomeres at the single-chromosome level. The potential of using frequency of short telomere for disease treatment monitoring is examined by analyzing the telomere length in lymphocyte of leukemia patients. The abundance of short telomeres was compared between healthy donors and patients with chronic myeloid leukemia (CML) to see whether it can be used to predict the efficacy of therapeutics. Moreover, the quantity of short telomeres was compared among patients with acute leukemia, patients in different phases of CML and healthy donors to see whether it can be used as a marker for disease progression prediction in CML. Reference [1] Blackburn E. H., Epel E. S., Lin J., Science,2015, 350, 1193-1198. [2]Collado M., Blasco M. A., Serrano M., Cell, 2007, 130, 223-233. [3] Deng Y., Chan S. S., Chang S., Nat. Rev. Cancer, 2008, 8, 450-458. [4] Yang LL, Zhu SB, Hang W, Wu LN, Yan XM, Anal. Chem., 2009, 81, 2555-2563. Figure 1 Disclosures No relevant conflicts of interest to declare.

Increased number of mast cells in the bone marrow of chronic myeloid leukemia may herald the pending myeloid transformation—the mast cell is an indicator of myeloid transformation

Background: Tumor cells are surrounded by many inflammatory cells, including mast cells (MCs), which can secrete several classic proangiogenic factors, resulting in endothelial cell proliferation and angiogenesis. However, the researches of the number of MC and microvessel density (MVD) in the bone marrow in chronic myeloid leukemia (CML) are rare. In this study, we aimed to investigate the relationship between tryptase-positive MCs and MVD in the different phases of CML. Methods: Bone marrow samples of 61 patients with CML and 20 healthy donors were collected from 2007 to 2017. Antibodies against the endothelial cell marker CD34 and against tryptase were used in immunohistochemistry. The diagnosis and counting of tryptase-positive MC and microvessel in bone marrow was at ×400 magnification. Results: MVD in CML group was higher than which in the control group, and the blast phase (BP) group had a higher MVD than which in chronic phase (CP) group (P Conclusions: The number of MCs and MVD might be markers for the outcome of patients with CML in the Chinese population.

WITHDRAWN: Expression profiles and biological implications of plasma miRNAs associated with chronic myeloid leukemia phases

// Ji Zhang 1, 2 , Yawen Jiang 1 , Xu Han 1 , Wenen Liu 3 , Xielan Zhao 4 and Jing Liu 1 1 Molecular Biology Research Center, School of Life Sciences, Central South University, Changsha 410078, China 2 Department of Hematology, The First Affiliated Hospital, University of South China, Hengyang 421001, China 3 Department of Clinical Laboratory, Xiangya Hospital of Central South University, Changsha, 410008, China 4 Department of Hematology, Xiangya Hospital of Central South University, Changsha, 410008, China Correspondence to: Jing Liu, email: jingliucsu@hotmail.com, liujing2@sklmg.edu.cn Ji Zhang, email: zhang_ji001@hotmail.com Keywords: plasma miRNA; chronic myeloid leukemia; expression profile; biological function; miR-451a Received: September 13, 2017 Accepted: November 16, 2017 Published: January 02, 2018 ABSTRACT microRNAs play important regulatory roles in hematologic malignancies, and dysregulation of circulating miRNAs serves as diagnostic, prognostic and predictive biomarkers in many diseases. The correlation of plasma miRNA profiles with the progression of chronic myeloid leukemia (CML) has not been investigated. We have applied microarrays to identify differentially expressed miRNAs, followed by qRT-PCR to validate candidate miRNAs from four sample pools including chronic phase (CP), accelerated phase(AP), blast crisis(BC) and healthy control. Clustering analyses revealed varying phase-specific patterns of plasma miRNA expression during CML progression. Different phases of CML showed differential expression profiles between sample pools during the progression. The functional annotation tool, DAVID, found that putative targets of dysregulated miRNAs in different phases of diease are involved in several important signaling pathways. Gradually decreased expression levels of miR-451a were validated in CML patients from the CP to AP and BC; when CML patients achieved major molecular response (MMR), miR-451a expression was increased and restored to normal range. These data provide an important resource for studies on CML progression and allow a better understanding of the fundamental differences in plasma miRNA expression profiles among the different phases of CML.

ApoptomiRs expression modulated by BCR–ABL is linked to CML progression and imatinib resistance

Chronic myeloid leukemia (CML) is a myeloproliferative disease characterized by the presence of Philadelphia chromosome (Ph) leading to expression of a BCR-ABL1 fusion oncogene. The BCR-ABL protein has a constitutive tyrosine kinase activity which is responsible for CML pathogenesis by promoting cell apoptosis resistance; however, the cellular and molecular mechanisms associated with BCR-ABL expression and apoptosis impairment in CML leukemic cells have not been fully elucidated. This study evaluated apoptomiRs and their predicted apoptotic genes in BCR-ABL(+) cells from patients in different phases of CML treated with tyrosine kinase inhibitor (TKI) according to their imatinib (IM) response by qPCR. Phosphotyrosine and c-ABL expressions in HL-60.BCR-ABL cells treated with TKI were done by Western blot. We found that dasatinib (DAS) modulated miR-let-7d, miR-let-7e, miR-15a, miR-16, miR-21, miR-130a and miR-142-3p expressions while IM modulated miR-15a and miR-130a levels. miR-16, miR-130a and miR-145 expressions were modulated by nilotinib (NIL). We observed higher miR-15a, miR-130b and miR-145; and lower miR-16, miR-26a and miR-146a expressions in CML-CP in comparison with controls. CML-AP patients showed low miR-let-7d, miR-15a, miR-16, miR-29c, miR-142-3p, miR-145, and miR-146a levels in comparison with CML-CP. We noted that the miR-26a, miR-29c, miR-130b and miR-146a expressions were downregulated in IM resistant patients in comparison with IM responsive patients. This study showed the modulation of apoptomiRs by BCR-ABL kinase activity and the deregulation of apoptomiRs and their predicted apoptotic target genes in different CML phases and after treatment with TK inhibitors. ApoptomiRs may be involved in the BCR-ABL(+) cell apoptosis regulation.

Does CD34 Staining Reflect the Angiogenic Process in the Bone Marrow? An Analysis of a Series of Chronic Myeloid Leukemia Patients.

Backgorund: Angiogenesis is associated with growth, dissemination and metastasis of tumours. Measurement of Microvascular Density (MVD) is a quantitative method of assessment of angiogenesis and would give a proportional co relate of the angiogenic process in tumours. The aim of this study is to measure the MVD by using CD34 staining in various phases of Chronic Myeloid Leukemia (CML) and type of CML (Granulocytic/Granulocytic Megakaryocytic) (G/GM) and to co-relate micro vascular densities with the grade of fibrosis. Bone marrow biopsy specimens of 30 CML patients and 20 non-CML (controls) cases that required bone marrow biopsy were subjected to CD34 staining and H&E staining. The mean MVD in CD34 slides was assessed by selecting hot spots and MVD was measured in these fields in high power (40 x magnification) and the mean MVD was calculated by taking the average of four hot spots per field. Grade of fibrosis and phase of CML, type (G/GM) were assessed in H&E slides. The controls were matched with respect to age and gender. Among 30 patients with CML, 21 were in chronic phase, five in accelerated and four in blast crisis. A normal distribution was obtained for MVD of both CML cases and controls using tests for normality. Comparison of mean MVD between CML and controls by student t-test showed a significant increase in MVD of CML cases (p = 0. 00026). However, no significant difference in MVD between the three phases viz, Chronic, accelerated and blast crisis phase (p = 0. 302) was obtained by using one way ANOVA. Comparison of Grade of fibrosis with MVD using independent t-test showed no significant difference in MVD between low (Grade1&2) and high grade (Grade 3&4) (p = . 805). No significant difference in MVD was obtained between G and GM types of CML using independent t-test (p = 0. 381). The study shows that there is a significant increase in MVD in CML cases than controls but no significant difference in MVD could be demonstrated between different phases of CML, histological types of CML and grades of fibrosis in CML.

BCR-ABL Splice Variants In Three Phases Of CML: Association With Disease Biology and Response To Imatinib

BackgroundPhiladelphia chromosome, a characteristic chromosomal translocation (breakpoint cluster region-Abelson [BCR–ABL]; t [9; 22] [q34; q11]) in chronic myeloid leukemia (CML) encodes a product, which is the target of tyrosine kinase inhibitors (TKIs). In most CML patients, during translocation, the break takes place within a 5.8-kb region on both sides of BCR exons12-16 (originally referred to as exons b1-b5), described as themajor breakpoint cluster region (M-bcr)1. It can be either between exons b2 and b3, or between exons b3 and b4. The ABL exon which is mostly inserted in break points of BCR is a2. As a result of alternativesplicing, fusion transcripts with either b2a2 or b3a2 splicing variantcan be produced. Occasionally, breakpoints occur in unusual places, resulting in generation of rare BCR-ABL transcripts (b2a3, b3a3, e1a2, e8a2, e19a2). Association of BCR-ABL splice variants with clinical outcome in different phases of CML has rarely been studied2. We studied BCR/ABL splice variants and their association with disease biology and response to imatinib in 3 phases of CML in 70 patients. MethodsTotal RNA was extracted and reverse transcribed. PCR primers and nested PCR protocol for the detection of BCR-ABL splice variants in CML patients were adopted from van Dongen et al., 1999 3. Data was analyzed using SPSS Software version 17. ResultsMedian age of the patients was 34 years; 10 patients were 18 or younger and there were 40 females. 26 patients were in chronic phase (CP), 26 in accelerated phase (AP) and 18 in blast phase (BP). Overall, the frequencies of BCR/ABL splice variants b3a2, b2a2 and b3a2+b2a2 were found in 49 (70%), 15 (21.4%) and 6 (8.6%) patients, respectively. No rare BCR-ABL transcripts were identified. Percentage of BCR-ABL splice variant b2a2 was similar in patients with CP (31) and BP (28) of CML and low in AP (7.75). While the percentage of BCR-ABL splice variant b3a2 was more common in AP (84.5) and BP (72) as compared to CP (54). The combined expression of both transcripts (b3a2 and b2a2) was found in 4 patients with CP and 2 in AP of CML but none in BP of CML (Table 1). The co-existence of b2a2 and b3a2 transcripts was observed only in male patients. The BCR-ABL transcripts had no correlation with the age. Patients with the splice variant b2a2 had a better response to imatinib treatment and better survival as compared to patients with b3a2. The patients expressing both transcripts (b3a2 and b2a2) also showed better survival as compared to patients with only b3a2 transcript (figure 1). [Display omitted] Discussion and ConclusionsWe found a higher percentage of BCR-ABL splice variant b3a2 in AP & BP as compared to CP. Patients with the BCR-ABL splice variant b2a2 had a better response to imatinib and better survival, which is in contrast to previous reports 4. Co-existence of two transcripts b3a2 and b2a2 was observed mostly in CP, and in some patients in AP; it was also associated with a better response to imatinib. Larger studies are needed to further define the role of BCR-ABL splice variants in different phases of CML and their association with response to TKIs and prognosis. Studies of BCR-ABL splice variants can provide further insights into CML biology and new targets for BCR-ABL positive leukemia treatment 1, 5.

The Musashi 2 mRNA Expression in the Course of CML.

Abstract 2552The Musashi (MSI) gene family members, MSI1 and MSI2, represent an evolutionarily conserved family of RNA-binding proteins that regulate mRNA translation through binding in their N-termini. High levels of MSI2 protein are associated with increased cell proliferation, decreased cell maturation, more aggressive hematologic malignancy diseases and worse clinical prognosis. Recently obtained data pointed to MSI2 playing an important role in acute myeloid leukemia (AML) and in deadly blast crisis of chronic myeloid leukemia (CML) (Ito et al. 2010 Nature 5; 466).In this study we screened the level of MSI2 mRNA in 49 patients in different phases of CML and with different response to therapy – 18 patients at diagnosis (DG), 5 in major molecular response (MMR), 4 in complete molecular response (CMR), 2 after bone marrow transplantation (BMT), 10 in hematology relaps (HR), 6 in accelerrated phase (AP), and 4 in blast crisis (BC), and in 6 healthy donors. The level of MSI2 mRNA was quantified by real-time reverse-transcriptase-polymerase chain reaction using in-house designed specific primers and TaqMan probe and normalized to B2M endogenous control. Expression ratios were calculated by ΔΔCt method, and the differences between groups were statistically evaluated using Mann Whitney test.We detected MSI2 expression in all samples. The median expression of mRNA MSI2 in patients at DG was 1,43 (0,33–3,28), in MMR 0,52 (0,20–0,62), in CMR 0,37 (0,30–0,63), after BMT 1,28 (1,02–1,54), in HR 0,41 (0,16–0,58), in AP 3,78 (1,94–13,69), in BC 15,17 (2,61–28,15). MSI2 expression was statistically up-regulated in patients in advanced phases of CML (AP, BC) when compared with patients in CP (P<0.0001). The difference between patients in DG and remaining patients in CP was also statistically significant (P= 0,0006). No correlation of MSI2 expression level in DG patients with their responsiveness to treatment, BCR-ABL transcript level or survival was found. No significant differences were observed among groups of patients in MMR, CMR, HR, and after BMT.In addition, in order to check whether MSI2 expression level can serve as a marker of CML progression we also retrospectively screened kinetics of MSI2 transcript in 5 CML patients monitored on average 27 months (18–48). During this period, 3 patients developed HR, 1 patient AP and 1 BC. In BC patient the MSI2 transcript level increased with progression of CML in accordance with the increase of leucocytes and BCR-ABL transcript level. In 1 patient with a rising AP BCR-ABL levels remained constant compared to sevenfold increase of the MSI2 transcript level. On the other hand in HR patients we detected a constant or even decreasing level of MSI2 transcript regardless of the increase of leucocytes and BCR-ABL.In summary, our results confirm the association of high MSI2 mRNA level with advanced phases of CML and indicate that increase of MSI2 mRNA level may serve as a valuable marker of advanced phases of CML. In particular for CML patients with constantly high level of BCR-ABL mRNA the monitoring of MSI2 level can be important tool for early recognition of CML progression. Potential contributions of MSI2 to leukemic pathogenesis and its regulation in CML progression remain unknown.Grant support: NT/12392-4 IGA MZ-CR. Disclosures:No relevant conflicts of interest to declare.

Epidemiological Study on Survival of Chronic Myeloid Leukemia (CML) and Ph+ Acute Lymphoblastic Leukemia (ALL) Patients with T315I Mutation. Final Analysis

The BCR-ABL T315I mutation is one of the major mechanisms of resistance to tyrosine kinase inhibitors (TKIs). Limited data have suggested that patients harboring a T315I mutation have poor outcomes. The objectives of this study were to estimate overall (OS) and progression-free survival (PFS) for CML in chronic (CP), accelerated (AP), or blastic (BP) phase, and Ph+ ALL patients who developed a T315I mutation; and describe the treatment pattern after T315I detection.Methods: This was a retrospective, multicenter observational study. Eligible patients included CML and Ph+ ALL patients who developed T315I mutation between 1999 and 2008. The medical records of 222 patients from 9 countries (France, Italy, Korea, USA, Germany, Singapore, Denmark, UK and Japan) were abstracted, and Kaplan-Meier plots and Cox proportional hazard models were used for survival analysis.Results: Median age at T315I detection was 54 (range, 18–84) years; 57% were male; 75% were Caucasian and 22% were Asian. Before T315I detection, 97% patients received imatinib (25% as a 1st line) and 50% received second generation TKIs. 16% of patients had other mutations detected before T315I detection. The median time between TKI treatment start and T315I detection was 29 months for CP, 15 for AP, 6 for BP, and 9 for Ph+ ALL. After T315I detection, 56% patients received second generation TKIs (30% started after T315I detection), 39% received hydroxyurea (33% started after T315I detection), 35% received imatinib (13% started after T315I detection), 26% received cytarabine, 21% received investigational drugs including 11% MK-0457, 17% underwent stem cell transplantation, and 6% received interferon alpha (5% started after T315I detection). At the time of T315I detection, T315I formed the predominant clone in 87% of patients; 23% had additional mutations detected (11% of these P-loop mutations). OS and PFS from T315I mutation detection are summarized in Table 1. In a preliminary analysis, the following covariates were associated with worse OS in Cox proportional hazard model (adjusted hazard ratio, 95% confidence interval): older age (by median, 2.30, 1.04–5.09) in Ph+ ALL patients, female gender in BP (1.73, 0.96–3.10); worse performance status in Ph+ ALL (1+ vs. 0; 2.18, 1.02–4.68); and detection of T315I by direct sequencing (vs. other methods) in AP (3.03, 0.89–10.29) and Ph+ ALL (2.33, 1.06–5.12). The effect of different treatments on OS will be available at the time of presentation.Conclusion: These results confirm that survival of patients harboring a T315I mutation is dependent on the disease phase at T315I detection. No clear treatment pattern after T315I detection was observed. Age, gender, performance status, and techniques used for T315I detection might be important prognosis factors affecting OS across different phases of CML and Ph+ ALL.Table 1. OS and PFS of CML and Ph+ ALL patients from T315I detectionCML CP (N=82)CML AP (N=38)CML BP (N=56)Ph+ ALL (N=46)Median follow up time (months)12.415.23.03.6Median OS (months) (95% CI)22.4 (18.2, 48.5)28.4 (15.9, 49.8)4.0 (2.0, 5.0)4.9 (3.4, 7.3)1-year OS Rate (95% CI)71% (58–80%)69% (50–81%)23% (13–36%)12% (3–27%)Median PFS (months) (95% CI)11.5 (9.2, 15.7)22.2 (9.0, N/A )1.8 (1.2, 4.0)2.5 (1.8, 3.6)1-year PFS Rate (95% CI)46% (34–57%)56% (38–70%)16% (7–27%)7% (1–19%)* Median survival and survival rates were calculated using Kaplan-Meier method.

Additional clonal abnormalities in Philadelphia-positive ALL and CML demonstrate a different cytogenetic pattern at diagnosis and follow different pathways at progression

The cytogenetic patterns in addition to the Philadelphia translocation in Philadelphia-positive (Ph+) ALL and chronic myeloid leukemia (CML) is heterogenous. We investigated 154 patients with Ph+ ALL at diagnosis or at relapse and 174 patients with different phases of CML. Ph+ ALL at diagnosis demonstrated a heterogenous pattern with a high frequency of numerical and structural chromosomal aberrations. CML at diagnosis presented with rare additional chromosomal changes. In Ph+ ALL, the pathway from diagnosis to relapse was characterized by the acquisition of a higher number of chromosomal aberrations, but the pattern of frequent aberrations at relapse did not differ from that observed at diagnosis. In contrast, in CML the pathway from chronic to the advanced phases was characterized by the acquisition of new chromosomal changes and by the development of karyotype complexity. In addition, the investigation of 10 cases of lymphoid blast crisis of CML showed significant differences in the karyotype in comparison to Ph+ ALL at diagnosis. Therefore, the karyotype can be helpful in discriminate de novo lymphoid blast crisis of CML from de novo Ph+ ALL. In conclusion, we were able to demonstrate that the cytogenetic patterns of Ph+ ALL and of CML are different at diagnosis and furthermore follow different pathways during progression or relapse.

Genomic p16 abnormalities in the progression of chronic myeloid leukemia into blast crisis: a sequential study in 42 patients.

The molecular abnormalities involved in the progression of chronic myeloid leukemia (CML) are poorly understood. Genetic alterations of the INK4A/ARF locus have been implicated in the lymphoid blast crisis (BC), but sequential studies are not available. The aim of this study was to contribute to a better knowledge of the status of such locus in the different phases of CML and to analyze the prognostic significance of its inactivation. Sequential assessment by quantitative real-time polymerase chain reaction (PCR) and conventional semiquantitative PCR of p16 exon 2 deletions was performed in 42 CML patients in whom paired DNA samples from the chronic phase and the BC were available. Samples of 10 healthy donors and 30 patients with nonleukemic myeloproliferative syndromes served as controls. The methylation status of the promoter region of the p16 gene was also studied by methylation-specific PCR. The concordance rate between the two PCR techniques was 97.8% (87/89). By real-time PCR, homozygous p16 deletions were found in 6 of 21 patients (29%) with lymphoid BC, whereas they were not observed in chronic-phase CML nor in 21 myeloid BC patients. Hypermethylation of the p16 gene was not detected in any of the lymphoid BC. No specific clinical profile was associated with homozygous p16 deletions. Therapeutic response and survival did not significantly differ in p16-deleted and p16 germline lymphoid BC patients. P16 gene deletions are detected in a substantial proportion of lymphoid BC of CML by quantitative real-time PCR analysis, but this is not associated with any clinico-hematological feature other than lymphoid phenotype and does not influence the patients' outcome. Such technique is simple and reliable to assess the p16 gene status.