Additional Chromosomal Abnormalities Research Articles

Prognostic Impact of Chromosomal Abnormalities and Copy Number Alterations Among Adults with B-Cell Precursor Acute Lymphoblastic Leukaemia Treated on UKALL14

Prognostic Impact of Chromosomal Abnormalities and Copy Number Alterations Among Adults with B-Cell Precursor Acute Lymphoblastic Leukaemia Treated on UKALL14

The influence of additive clonal chromosome abnormalities in Ph negative cells on the efficacy of chronic myeloid leukemia

Objective: To investigate the influence of additional clonal chromosome abnormalities in Ph negative cells (CCA/Ph(-)) on the efficacy of chronic myeloid leukemia (CML) after tyrosine kinase inhibitors (TKI) treatment. Methods: The clinical data of 28 CML patients with CCA/Ph(-) treated in Henan Cancer Hospital from July 2014 to December 2017 were analyzed retrospectively. The univariate analysis was carried out by Kaplan-Meier method. Multivariate analysis was done by Cox proportional risk model. Results: A total of 28 CCA/Ph(-)patients were recruited including 17 males and 11 females with median age of 42.5 years old. The most common CCA/Ph(-)were trisomy 8 (60.7%), monosomy 7 (14.3%). 64.3% CCA/Ph(-)were transient and 35.7% recurrent (more than 2 times). Cytopenia in two or three lineages of peripheral blood was seen in 42.9% patients. As to the efficacy, 89.3% patients achieved major cytogenetic response (MCyR), 25% with major molecular response (MMR). The median follow-up time was 26.5 months. Treatment failure (TF) of TKI occurred in 32.1% patients with median duration of response 8 (1-41) months. Univariate analysis showed that TF rate was significantly correlated with the frequency of CCA/Ph(-)and cytopenia (all P<0.05). The MMR rate was also significantly correlated with cytopenia (P<0.05). Cytopenia of two lineages or pancytopenia was an independent risk factor related to MMR rate (RR=3.868, 95%CI 1.216-12.298, P=0.022) . Conclusions: Cytopenia in CCA/Ph(-)appears to be an independent risk factor of MMR in CML patients with TKI treatment. The recurrent CCA/Ph(-)may link to higher treatment failure rate. Drug withdrawal or alternative strategy should be considered according to response and the ABL kinase mutations.

Genome Sequencing Explores Complexity of Chromosomal Abnormalities in Recurrent Miscarriage

Recurrent miscarriage (RM) affects millions of couples globally, and half of them have no demonstrated etiology. Genome sequencing (GS) is an enhanced and novel cytogenetic tool to define the contribution of chromosomal abnormalities in human diseases. In this study we evaluated its utility in RM-affected couples. We performed low-pass GS retrospectively for 1,090 RM-affected couples, all of whom had routine chromosome analysis. A customized sequencing and interpretation pipeline was developed to identify chromosomal rearrangements and deletions/duplications with confirmation by fluorescence in situ hybridization, chromosomal microarray analysis, and PCR studies. Low-pass GS yielded results in 1,077 of 1,090 couples (98.8%) and detected 127 chromosomal abnormalities in 11.7% (126/1,077) of couples; both members of one couple were identified with inversions. Of the 126 couples, 39.7% (50/126) had received former diagnostic results by karyotyping characteristic of normal human male or female karyotypes. Low-pass GS revealed additional chromosomal abnormalities in 50 (4.0%) couples, including eight with balanced translocations and 42 inversions. Follow-up studies of these couples showed a higher miscarriage/fetal-anomaly rate of 5/10 (50%) compared to 21/93 (22.6%) in couples with normal GS, resulting in a relative risk of 2.2 (95% confidence interval, 1.1 to 4.6). In these couples, this protocol significantly increased the diagnostic yield of chromosomal abnormalities per couple (11.7%) in comparison to chromosome analysis (8.0%, chi-square test p=0.000751). In summary, low-pass GS identified underlying chromosomal aberrations in 1 in 9 RM-affected couples, enabling identification of a subgroup of couples with increased risk of subsequent miscarriage who would benefit from a personalized intervention.

Effect of Chromosomal Karyotype on the Prognosis of Patients with Acute Promyelocytic Leukemia in Condition of the Maintenance Treatment Based on Arsenic Trioxide

To investigate the effect of chromosomal karyotype on the prognosis of patients with acute promyelocytic leukemia (APL) in condition of the maintenance treatment based on arsenic trioxide. The patients with acute promyelocytic leukemia for last 12 years in our hospital were retrospectively collected. The patients mainly treated with arsenic trioxide in maintenance protocol were selected and followed up. All the patients were divided into 3 groups according to cytogenetic data: single t (15; 17) group, t (15; 17) with additional chromosomal abnormality (ACA) group, and normal karyotype group. Then, the prognostic significance of ACAs and complex karyotype were investigated in APL patients. There were 57 cases in the single t (15; 17) group, in which 8 cases died in the first month after induction treatment with early mortality rate of 14%. There were 21 patients in t (15; 17) with ACA group, in which 4 cases died in the first month with early mortality rate of 19%. There were 15 cases in normal chromosome group, in which 5 cases died in the first month with the early mortality rate of 33.3%. There was no statistical difference in the early mortality among 3 groups. All the remaining 76 patients achieved complete hematological remission. These patients were followed up. The median follow-up time was 43.9 months. Among them, only 2 patients in single t (15; 17) group and 1 patient in t (15; 17) with ACA group relapsed. No patient relapsed in normal karyotype group. The relapse rate was 3.5% in single t (15; 17) group and 4.2% in t (15; 17) with ACA group, respectively. There was no statistical difference in the overall survival and disease-free survival rates among 3 groups. Further analysis showed that the patients with complex chromosome karyotypes had lower relapse-free survival rates, but overall survival rates were not significantly different in 3 group. In general, ACA can not affect the prognosis of patients with acute promyelocytic leukemia in condition of the maintenance treatment based on arsenic trioxide, but the complex chromosomal karyotype may reduce the relapse-free survival rates.

Potential role for second‑generation tyrosine kinase inhibitors in patients with chronic myeloid leukemia harboring additional clonal chromosome abnormalities: A retrospective CML Cooperative Study Group analysis.

Tyrosine kinase inhibitor (TKI) treatment is the standard of care for patients with chronic myeloid leukemia (CML). Even in the imatinib era, the presence of 'clonal chromosomal abnormalities' in the Philadelphia chromosome (CCA/Ph+) at diagnosis reportedly increased the risk of disease progression and predicted shorter survival. However, it remains unclear whether CCA/Ph+ is a poor prognostic marker in the era of new‑generation TKIs. The data of patients with CML in the chronic phase (CP) that were extracted from the CML Cooperative Study Group database were retrospectively analyzed. Of the 328 eligible patients, 33 (10.1%) had CCA/Ph+, including 9 major route and 24 minor route aberrations. The characteristics of patients with and without CCA/Ph+ were similar; however, the proportion of blasts was higher among patients with CCA/Ph+. Notably, the survival rate of patients with CCA/Ph+ was not inferior to that of patients without CCA/Ph+, and there were no differences in responses to TKIs. All 9 patients with major route CCA/Ph+ attained a major molecular response (MMR) with no disease progression, and 8 ultimately achieved a deep molecular response. In particular, the median interval between TKI initiation and achievement of MMR was shorter in patients initially treated with a second‑generation TKI than in those treated with imatinib (5 vs. 10 months). The present retrospective study, thus, revealed favorable treatment outcomes in CML‑CP patients with CCA/Ph+ treated with second‑generation TKIs. The data indicated that administering second‑generation TKIs as first‑line treatments is preferable in CML‑CP patients with CCA/Ph+.

Genetic analysis of products of conception using a HLPA/SNP-array strategy

BackgroundFetal chromosomal abnormalities was the most frequent cause of miscarriage, and the traditional testing method G-banded karyotyping has limitations. Then high-throughput ligation-dependent probe amplification (HLPA) and single nucleotide polymorphism array (SNP-array) were introduced for genetic analysis on products of conception (POC).MethodsHLPA and SNP-array analysis were combined. POC samples were initially tested using HLPA, followed by SNP-array analysis on samples that were found to be normal by HLPA.ResultsOf the 326 POC samples tested, the overall abnormality rate was 54.6% (178/326), including 44.8% (146/326) chromosomal abnormalities identified by HLPA and 9.8% (32/326) additional chromosomal abnormalities further detected by SNP-array.ConclusionsThe combination of HLPA and SNP-array analysis is an efficient and cost-effective strategy for genetic analysis of POC.

B-Lymphoid Blast Phase of Chronic Myeloid Leukemia: A Case Report and Review of the Literature

Abstract Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder characterized by a reciprocal translocation, t(9;22)(q34.1;q11.2). This leads to fusion of the BCR and ABL1 genes, encoding an active tyrosine kinase that causes unregulated proliferation of the myeloid lineage. The BCR/ABL1 fusion protein is found not only in CML, but also in a subset of de novo B-lymphoblastic leukemia (B-LL). However, the fusion protein in CML is characteristically the slightly longer p210 variant, whereas the p190 variant is more frequently found in B-LL. Without treatment, CML will progress to accelerated and/or blast phase (BP). Disease progression is often characterized by accumulation of additional chromosomal abnormalities. The development of tyrosine kinase inhibitor (TKI) therapy that targets BCR/ABL1 has revolutionized treatment of CML and vastly improved outcomes, although the disease can still progress despite TKI therapy. Blast phase most commonly manifests as myeloid BP; however, up to 30% of BP presents as lymphoid BP (LBP), typically of the B-cell lineage. The B-lymphoblasts of LBP have a phenotype indistinguishable from that of de novo B-LL. However, LBP typically carries the p210 BCR/ABL transcript and may show distinct chromosomal anomalies, including loss of chromosome 9p. The prognosis for CML-BP is poor, although survival has improved with TKI therapy and stem cell transplant, and LBP has been associated with superior survival compared with myeloid BP. Here we present a case of CML in B-lymphoid BP and review the current literature.

Prognostic Impact of Additional Chromosomal Abnormalities in Egyptian Chronic Myeloid Leukemia Patients

Prognostic Impact of Additional Chromosomal Abnormalities in Egyptian Chronic Myeloid Leukemia Patients

Allogeneic stem cell transplantation in second complete remission for core binding factor acute myeloid leukemia: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

Core binding factor acute myeloid leukemia (AML) comprises two subtypes with distinct cytogenetic abnormalities of either t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22). Since long-term response to chemotherapy in these leukemias is relatively good, allogeneic hematopoietic stem cell transplantation is considered in patients who relapse and achieve second complete remission. To evaluate the outcomes of allogeneic transplantation in this indication, we studied 631 patients reported to the European Society for Blood and Marrow Transplantation Registry between the years 2000 and 2014. Leukemia-free survival probabilities at two and five years were 59.1% and 54.1%, while overall survival probabilities were 65% and 58.2%, respectively. The incidence of relapse and risk of non-relapse mortality at the same time points were 19.8% and 22.5% for relapse and 20.9% and 23.3% for non-relapse mortality, respectively. The most important adverse factors influencing leukemia-free and overall survival were: leukemia with t(8;21), presence of three or more additional chromosomal abnormalities, and Karnofsky performance score <80. Relapse risk was increased in t(8;21) leukemia and associated with additional cytogenetic abnormalities as well as reduced intensity conditioning. Measurable residual disease in molecular evaluation before transplantation was associated with increased risk of relapse and inferior leukemia-free survival.

Clinical Retrospective Analysis of Chronic Myeloid Leukemia in Myeloid Blast Crisis

To retrospectively analyze the clinical manifestation, laboratorial test features and prognosis of patients with CML in myeloid blast crisis. The clinical data of 10 patients with CML in myeloid blast crisis admitted in Chinese PLA General Hospital from June 2011 to May 2018 were collected, and their clinical features, laboratorial data and long-term survival were analyzed. The median age of these 10 cases was 32.5 (23-73) years old. Nine cases had chronic phase history. The median chronic phase was 17(4-84) months. All the 10 cases had splenomegaly; B-ultrasonography showed that the median spleen size was 5.2 (4-7.8) cm in thickness, and 14.6 (11.4-19.8) in length. When chronic myeloid leukemia was in blast crisis, the median WBC count was 41.705（11.9-344.41）×109 /L and the median platelet count was 159 (13-2326) ×109 /L. The Ph+ chromosome and BCR-ABL1 fusion gene coulld be detected in all the cases. The chromosome karyotyping showed that additional chromosome abnormalities were found in 5 cases. One case was of low diploid, and two cases were with complex karyotype. ABL1 mutation was detected in 6 out of these 10 cases. ABL1 T315I mutation was detected in 2 of them and one was with deletion of combined P53 in genetic tests. The median follow-up time was 10.5(0.2-78) months. There were 5 cases treated sequentially by chemotheraphy with or without TKI and allo-HSCT. Three cases reached CP2 before transplantation. Among them, two cases still survived without progression for 67 months and 69 months after the transplantation respectively. One case died of transplantation-related mortality (suffered from cerebral hemorrhage 7 months after the transplantation). Two cases were NR before the transplantation, and both died of disease relapse or progression at the time points of one or three months after the transplantation. Five cases treated by TKI ± chemotheraphy and without HSCT succumbed to disease progression. The median time was 6(0.2-22) months. CML patients in myeloid blast crisis treated by chemotheraphy combined with TKI gain CP2, the survival time of patients treated by sequential allo-HSCT is prolonged.

Roles of the hexosamine biosynthetic pathway and pentose phosphate pathway in bile acid-induced cancer development.

Esophageal squamous cell carcinomas (ESCCs) as well as adenocarcinomas (EACs) were developed in rat duodenal contents reflux models (reflux model). The present study aimed to shed light on the mechanism by which bile acid stimulation causes cancer onset and progression. Metabolomics analyses were performed on samples of neoplastic and nonneoplastic tissues from reflux models, and K14D, cultivated from a nonmetastatic, primary ESCC, and ESCC‐DR, established from a metastatic thoracic lesion. ESCC‐DRtca2M was prepared by treating ESCC‐DR cells with taurocholic acid (TCA) to accelerate cancer progression. The lines were subjected to comprehensive genomic analyses. In addition, protein expression levels of glucose‐6‐phosphate dehydrogenase (G6PD), nuclear factor kappa B (NF‐κB) (p65) and O‐linked N‐Acetylglucosamine (O‐GlcNAc) were compared among lines. Cancers developed in the reflux models exhibited greater hexosamine biosynthesis pathway (HBP) activation compared with the nonneoplastic tissues. Expression of O‐GlcNAc transferase (OGT) increased considerably in both ESCC and EAC compared with nonneoplastic squamous epithelium. Conversely, cell line‐based experiments revealed the greater activation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. G6PD overexpression in response to TCA exposure was observed. Both NF‐κB (p65) and O‐GlcNAc were expressed more highly in ESCC‐DRtca2M than in the other cell lines. Moreover, ESCC‐DRtca2M cells had additional chromosomal abnormalities in excess of ESCC‐DR cells. Overall, glucose metabolism was upregulated in both esophageal cancer tissue and cell lines. While bile acids are not mutagenic, chronic exposure seems to trigger NF‐κB(p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression. Glucose metabolism was upregulated in both esophageal cancer tissue and cell lines, and the HBP was activated in the former. The cell line‐based experiments demonstrated upregulation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. While bile acids are not mutagenic, chronic exposure seems to trigger G6PD overexpression and NF‐κB (p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression.

SIGNIFICANCE OF ADDITIONAL CHROMOSOMAL ABNORMALITIES FOR THE OUTCOMES AFTER THE SECOND LINE NILOTINIB THERAPY IN THE CHRONIC MYELOID LEUKEMIA PATIENTS

Background. There is limited information about impact of additional chromosome aberrations (ACA) on the efficacy of the 2nd line nilotinib therapy. Objective. The aim of the study was to analyze significance of ACAs for the outcome after second line tyrosine kinase inhibitors (TKI) therapy with nilotinib in the chronic myeloid leukemia (CML) patients, who experienced previous imatinib therapy failure. Methods. The CML patients in chronic phase treated with nilotinib after imatinib failure were analyzed for outcomes. Results. Among a total of 114 patients, 18 patients (15.8%) had ACAs at the beginning of the 2nd line therapy with nilotinib. Seven patients (38.9%) of 18 had variant translocations and 11 patients (61.1%) had other chromosomal abnormalities in addition to t(9;22), known as clonal evolution. Complete cytogenetic response (CCR) at 12 months was achieved in 37.5%, 42.8% and 45.5% (p=0.842) of patients with classic t(9;22) translocation, variant translocations and ACAs respectively. In the patients with variant translocations t(9;V;22) or clonal evolution treated with nilotinib after the imatinib failure, the CCR and major molecular response (MMR), event free survival (EFS), progression free survival (PFS) and overall survival (OS) rates did not differ from those in the CML patients with t(9;22) only. At the same time quantitative characteristics of leukemic and ACA clones had prognostic value for CCR. The increased number of Ph-positive cells and the number of cells with the ACA at the start of nilotinib therapy reduced the probability of CCR. Conclusions. Higher nilotinib inhibitory activity compare with imatinib allows us to overcome imatinib resistance in the CML patients regardless of the ACA presence at the beginning of nilotinib therapy.

Clinical implications of cytogenetic heterogeneity in Philadelphia chromosome positive (Ph+) adult B cell acute lymphoblastic leukemia following tyrosine kinase inhibitors and chemotherapy regimens

We retrospectively studied a cohort of 144 adults with Philadelphia chromosome/BCR-ABL1 positive B acute lymphoblastic leukemia (Ph + B-ALL) to assess the clinical implications of cytogenetic heterogeneity in this disease. The study group included 85 men and 59 women that were sorted into 6 subgroups based on karyotypic findings in the stemline as follows: 32 patients with t(9;22) as a sole aberration, 23 with t(9;22) plus 1 additional chromosomal abnormality (ACA), 26 with t(9;22) as part of a complex karyotype, 18 showing a variant-/complex- t(9;22), 30 with t(9;22) as the stemline with ACAs in the sideline(s), and 15 patients who had the t(9;22) and hyperdiploidy. In 89 patients 1 clone was identified; 41 had 2 clones and 14 had ≥ 3 clone(s). The median overall survival (OS) was 25.6 months and the median relapse-free survival (RFS) was 20.6 months. Patients with variant-/complex- t(9;22) had poorer OS and RFS when compared with all other subgroups combined (P = 0.0018 and P = 0.0049, respectively). In addition, patients with ≥ 2 clones had worse OS and RFS than patients with 1 clone (P = 0.0179 and P = 0.0429, respectively). Multivariate analysis confirmed that variant-/complex-t(9;22) and clone number are independent risk factors. We suggest that conventional chromosomal analysis is of clinical importance for risk stratification of B-ALL patients.

PB1937 CHROMOSOMAL ABERRATIONS IN CHRONIC MYELOID LEUKEMIA AND THEIR IMPACT ON RESPONSE TO CONVENTIONAL TYROSINE KINASE INHIBITORS AND RISK OF BLASTIC TRANSFORMATION.

Background:Chronic Myeloid Leukemia(CML) is a common hematological malignancy with tyrosine kinase inhibitors(TKI) forming the main stay of treatment.Aims:The purpose of this project was to study the clinical presentation of patients with CML harboring additional chromosomal abnormalities at diagnosis and disease outcomes.Methods:This is a retrospective chart review of all patients who were diagnosed with CML in chronic phase (CP) with additional chromosomal abnormalities (ACAs) over a period of 5 years from 2010 to 2015 at our institution.Results:Response to initial TKI A total of 283 patients were diagnosed with CML from January 2010 to January 2015. Thirty one patients were found to have ACAs at the time of diagnosis in addition to BCR‐ABL fusion gene.23 patients (74.2%) were males whereas 8(25.8%) were females. 13(41.9%) were in the age group of 31 to 50 years. 30 patients were started on Imatinib and one on Nilotinib. 16 patients (51.6%) achieved complete hematological response within 3 months. However a complete molecular and cytogenetic response was never achieved in 17 (54.8%) and 18 (58.1%) patients respectively.Cytogenetics Analysis and ACAs Conventional cytogenetic analysis revealed that 11 (35.5%) of patients had variant Philadelphia chromosome followed by 7 patients (22.6%) with trisomy 8. 5 patients (16.1%) had multiple chromosomal abnormalities including trisomy 8, deletion 1 and isochrome 17q.Risk of blastic transformation Eight patients (25.8%) transformed to acute myeloid leukemia(AML) whereas 3 (9.7%) patients had a transformation to acute lymphoblastic leukemia(ALL).Therapy and response in transformed patients Out of the 11 patients who transformed to AML and ALL, 6 patients underwent induction chemotherapy while 5 were not considered fit for it on account of poor performance score and lack of resources. Out of these 6 patients, none responded to induction chemo.Summary/Conclusion:In summary, this study aimed to look at the clinical presentation of patients with CML harboring additional chromosomal abnormalities at diagnosis, cytogenetic analysis, risk of blastic transformation and response to treatment in transformed patients. Despite an early hematological response, more than half of the patients failed to achieve complete molecular and cytogenetic response which clearly shows suboptimal response to the tyrosine kinase inhibitors in this particular set of CML patients. There was transformation to acute leukemia in 35.5% of patients. We were able to give induction chemotherapy to only 6 out of 11 patients and none of them responded to it. This study showed that presence of ACA at the time of diagnosis is a high risk feature for patients with CML and confers poor prognosis when treated with conventional TKI. Further studies are required in our population regarding alternative therapy for such patient population.

Occurrence of other cancers in patients with chronic lymphocytic leukemia and mutations in protection of telomeres 1 (POT1) gene.

7529 Background: Mutations in POT1 gene in CLL lead to uncapping of the telomeric ends, causing fusion events and chromosomal aberrations. POT1 is mutated in approximately 4% of pts with CLL. Recent studies reported germline variants in POT1 in pts with familial CLL and in familial melanoma, cardiac angiosarcoma and glioma. We evaluated pts characteristics and the presence of other cancers (OC) in pts with CLL with POT1 mutation seen at our institution. Methods: We performed next generation sequencing (NGS)-based analysis for the detection of mutations in 29 genes frequently mutated in pts with CLL using blood and/or bone marrow samples containing a minimum of 10% clonal B-cells from 1467 pts diagnosed with CLL. Clinical characteristics, prognostic factors (FISH and IGHV status), personal and familial history of OC were collected in pts with POT1 mutations. Results: Mutations in POT1 were found in 52 of the 1467 pts studied (3.5%). Pts with POT1 mutation were young (median age 59 years), commonly presented with early stage disease (Binet stage A 69% vs B/C 31%: p=0.0046 and Rai stage 0-I 65% vs II-IV 35%; p=0.043) and predominantly male (37 male vs 15 female). According to FISH, the more frequent abnormalities were del13q (33%), no abnormalities (25%) and del11q (21%). IGHV status was more commonly unmutated (69%). The most frequent DNA mutations associated with POT1 were NOTCH1 (44%), TP53 (27%) and SF3B1 (23%). Other cancers (excluding non-melanoma skin cancer) were reported in 19 of the 52 pts with POT1 mutation (37%). The most common types were prostate cancer (12%), malignant melanoma (10%) and kidney cancer (8%). Twelve (23%) pts were diagnosed with OC before and 7 pts (13%) after the diagnosis CLL (Table). Four (8%) pts had more than one other cancer diagnoses. Twenty-eight (54%) pts had one of more first degree relatives with history of cancer. Conclusions: POT1 mutations were observed in 3.5% of pts with CLL. These pts are young and often have unmutated IGHV. We observed a high occurrence of OC, particularly malignant melanoma and kidney cancer in these pts. Additional studies are ongoing to determine the proportion of pts with germline POT1 mutation, the distribution of variant allelic frequencies and additional chromosomal abnormalities in pts with OC. Other Cancers in 52 CLL pts with POT1. [Table: see text]

Caractéristiques préthérapeutiques et évolutives des patients atteints de la leucémie myéloïde chronique à Abidjan Côte d’Ivoire

The diagnosis of chronic myeloid leukemia is based on the presence of translocation t(9,22). Additional cytogenetic abnormalities may exist at diagnosis and have prognostic value. The authors evaluated the relationship between these additional chromosomal abnormalities, clinical presentation, and therapeutic response. In a retrospective and comparative study from 2005 to 2015, at Yopougon university hospital, 51 cases of myeloid leukemia were selected, including 22 cases with additional chromosomal abnormalities. Thirteen types of additional Ph1 abnormalities were detected in one group, with a median age of 39years (13-73); a sex ratio of 1.4 and a low social class (49%). The median consultation time is 13months (2-29). Hepatomegaly (54%, P=0.05); fever (81.8%, P=0.0017); bone pain (63.6%, P=0.0001); lymphadenopathies (27.3% P=0.014); poor general condition [WHO>1 (77.3%, P=0.001)], high Sokal index (63.6%, P=0.0019), eosinophilia>5% (72.7, P=0.02) and circulating blastosis were found more frequent in the group with additional abnormalities treated with imatinib mesylate. We obtained 13.6% hematologic remission and 22.7% cytogenetic remission (P=0.02). The average survival was relatively short (20months vs. 76.4months, Log-rank<0.0001). We deplored a high death rate (59.1%). The presence of an additional anomaly constitutes a pejorative element refractory to imatinib.

Genetics and tyrosine kinase inhibitors of chronic myeloid leukemia

Chronic myeloid leukemia (CML) is caused by a reciprocal translocation between 9q34 and 22q11, which produces a chimeric BCR-ABL oncogene located on the Philadelphia chromosome i.e. rearranged 22. The fusion gene implicates in the overexpression of tyrosine kinase through binding with ATP in signal transduction. Therefore, targeted drug development aimed at inhibitors of tyrosine kinase (TKI) and formulated imatinib, which resulted in miraculous disease free survival in majority of the CML patients. However, drug-resistance remained a problem due mainly to emergence of missense point mutations in and around the BCR-ABL kinase domain. Loss of its sensitivity to leukemic stem cells guided development of altered TKIs such as dasatinib, nilotinib, bosutinib and ponatinib—each having specific sensitivity to different amino acid residues (T315I, Y253F/H, E255K/V, M351T, G250E, F359C/V, H396R/P, M244V, E355G, F317L, M237I, Q252H/R, D276G, L248V, F486S), have been implicated in ~ 85% of CML. At chromosomal level, trisomy 8, isochromosome 17q, amplification of the Philadelphia chromosome, additional translocations and complex karyotype are described in TKI-resistant CML. Therefore, mutational events at kinase domain and additional chromosome abnormalities could be considered for development and initiation of TKI-therapy, and cross-talk of complex mutations could lead to formulation of personalized TKI.

Allogeneic hematopoietic cell transplantation improves outcome of adults with t(6;9) acute myeloid leukemia: results from an international collaborative study

Acute myeloid leukemia (AML) with t(6;9)(p22;q34) is a distinct entity accounting for 1-2% of AML cases. A substantial proportion of these patients have a concomitant FLT3-ITD. While outcomes are dismal with intensive chemotherapy, limited evidence suggests allogeneic hematopoietic cell transplantation (allo-HCT) may improve survival if performed early during first complete remission. We report on a cohort of 178 patients with t(6;9)(p22;q34) within an international, multicenter collaboration. Median age was 46 years (range: 16-76), AML was de novo in 88%, FLT3-ITD was present in 62%, and additional cytogenetic abnormalities in 21%. Complete remission was achieved in 81% (n=144), including 14 patients who received high-dose cytarabine after initial induction failure. With a median follow up of 5.43 years, estimated overall survival at five years was 38% (95%CI: 31-47%). Allo-HCT was performed in 117 (66%) patients, including 89 in first complete remission. Allo-HCT in first complete remission was associated with higher 5-year relapse-free and overall survival as compared to consolidation chemotherapy: 45% (95%CI: 35-59%) and 53% (95%CI: 42-66%) versus 7% (95%CI: 3-19%) and 23% (95%CI: 13-38%), respectively. For patients undergoing allo-HCT, there was no difference in overall survival rates at five years according to whether it was performed in first [53% (95%CI: 42-66%)], or second [58% (95%CI: 31-100%); n=10] complete remission or with active disease/relapse [54% (95%CI: 34-84%); n=18] (P=0.67). Neither FLT3-ITD nor additional chromosomal abnormalities impacted survival. In conclusion, outcomes of t(6;9)(p22;q34) AML are poor with chemotherapy, and can be substantially improved with allo-HCT.

Conventional and molecular cytogenetic studies to characterize 32 complex variant Philadelphia translocations in patients with chronic myeloid leukemia.

BCR/ABL1 gene fusion is the hallmark of chronic myeloid leukemia (CML), and is generated in 5-10% of patients by a variant translocation involving 9q34, 22q11.2 and one or more additional genomic regions. The objective of the present study was to characterize, by conventional and molecular cytogenetics, 32 complex variant Philadelphia (Ph) translocations present at diagnosis in patients with CML. The chromosomes most frequently involved were 1 and 5, and the breakpoint most frequently involved was 12p13. The q-chromosome arm was more frequently involved (60%) than the p-arm. The breakpoints were located in the G-light bands in the majority of cases (85%). Additional chromosomal abnormalities were observed in 6 out of 32 (19%) patients. In conclusion, the combination of conventional and molecular cytogenetics studies has allowed us to: i) Detect and quantify the BCR/ABL1 fusion gene; ii) characterize the complex variant translocations and detect cryptic translocations; iii) confirm that the breakpoints are commonly localized in the G-light bands; (iv) confirm that the genesis of variant translocations could be via either the one-step or two-step mechanisms; and v) to report new cases of complex variant translocations.

7. Additional structural chromosomal abnormalities have a negative prognostic effect in patients with inv(16)/t(16;16) acute myeloid leukemia (AML)

Additional chromosomal abnormalities (ACAs) are considered as having no prognostic effect in inv(16)/t(16;16)/CBFB-MYH11 AML patients. However, many patients with ACAs cannot be cured by the standard-of-care therapy. This study included 264 inv(16)/t(16;16)/CBFB-MYH11 AML patients (M/F = 148/116; median age: 49, range 2-89 years). During a median follow-up of 34 months (range 1-190 months), 82 patients died, 169 achieved a complete remission and 13 had a partial response. Among 234 patients with abnormal karyotype, 218 had inv(16)(p13q22) and 16 had t(16;16)(p13;q22); and 110 (47%) had inv(16)/t(16;16) as the sole abnormality (Group A), 72 (30.8%) had one additional abnormality (Group B), and 52 (22.2%) had two or more abnormalities (complex karyotype, Group C). Of the additional abnormalities, +8 (n = 53) and +22 (n = 52) were most common, followed by 7q-/-7 (n = 28), +21 (n = 19 and –Y (n = 9). Structural abnormalities other than inv(16)/t(16;16) were found in 39 (16.7%) patients. Patients with ACA as a group (Groups B&C, n = 124) did not show inferior overall survival compared to Group A (median survival: 66 vs. 71 months, p = 0.5828). However, Group C showed a significantly shorter survival compared to patients in Groups A&B (n = 182) (median survival: 48 vs. 76 months, p = 0.0165). More interestingly, patients with additional structural abnormalities (n = 39) had a poorer prognosis than patients with additional numerical changes (n = 85) (median survival: 42 vs.146 months, p = 0.0123). This study shows that a complex karyotype, especially, additional structural abnormalities, predicts a poorer prognosis. Conventional chromosomal analysis of inv(16)/t(16;16)/CBFB-MYH11 AML patients appears to have value in stratifying patients with these neoplasm.