scholarly journals Clinically useful flow cytometry approach to identify immunophenotype in acute leukemia

2019 ◽  
Vol 47 (4) ◽  
pp. 1483-1492
Author(s):  
Guifang Ouyang ◽  
Zhijuan Xu ◽  
Danjie Jiang ◽  
Huiling Zhu ◽  
Yi Wang ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Acute Leukemia ◽  
Fusion Gene ◽  
Lymphoblastic Leukemia ◽  
Predictive Marker ◽  
Antigen Expression ◽  
Break Point ◽  
Leukemic Cells ◽  
Useful Flow ◽  
Marker Cluster

Objectives Acute leukemia (AL) is a highly heterogeneous malignant disease caused by hematopoietic cell abnormalities. Our study investigated the potential for immunophenotyping of leukemic cells via flow cytometry and the clinical usefulness of this approach in treatment of AL. Methods Bone marrow (BM) specimens were collected to detect antigen expression on hematopoietic cells in pre-treatment samples from patients with AL. In addition, fraction survival curves were calculated using the Kaplan-Meier method to explore the effect of markers on prognosis in AL. Results Expression levels of immunophenotypic markers in patients with acute lymphoblastic leukemia (ALL) were significantly different from those in patients with acute myeloid leukemia (AML). In addition, there was a potential association between the surface marker, cluster of differentiation 2 (CD2), and fraction survival in AML. However, no similar result was found in ALL. Moreover, genetic tests showed greater positive variation of the break point cluster-Abelson tyrosine kinase ( BCR-ABL) fusion gene in samples from patients with ALL than in samples from patients with AML. Conclusions We have shown a rapid and effective flow cytometry method that enables the identification of immunophenotype in AL. Moreover, CD2 may constitute a predictive marker for prognosis in patients with AML.

scholarly journals 14q32 translocations are associated with mixed-lineage expression in childhood acute leukemia

Blood ◽  
1990 ◽  
Vol 76 (1) ◽  
pp. 150-156 ◽  
Author(s):  
Y Hayashi ◽  
CH Pui ◽  
FG Behm ◽  
AH Fuchs ◽  
SC Raimondi ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Lymphoblastic Leukemia ◽  
Antigen Expression ◽  
Leukemic Cells ◽  
Entire Cohort ◽  
Break Points ◽  
Acute Nonlymphoblastic Leukemia ◽  
B Lineage ◽  
Childhood Acute Leukemia ◽  
14Q32 Translocation

The frequency and characteristics of childhood acute leukemia with a 14q32 translocation [other than the t(8;14)(q24;q32)] were determined in 335 cases of newly diagnosed acute lymphoblastic leukemia (ALL) and 105 cases of acute nonlymphoblastic leukemia (ANLL). Ten children, representing 2.3% of the entire cohort, had this abnormality (1.5% of ALL patients and 4.8% of ANLL patients). By French-American-British (FAB) criteria, 4 cases were classified as L1, 1 as L2, 2 as M1, 1 as M2, and 2 as M5. Remarkably, mixed-lineage expression was found in 6 of these 10 cases, but in only 21 of the other 430 cases without a 14q32 translocation (P less than .001). Leukemic cells from 5 of these 6 cases (4 ANLL, and 1 ALL) coexpressed CD13, a myeloid-associated antigen, and CD2, a T-cell-associated antigen; blasts from the sixth case (ALL) coexpressed CD13 and CD19, a B-lineage-associated antigen. Thus, in addition to the well-described 11q23 translocations and t(9;22), 14q32 translocations also appear to be associated with mixed lineage antigen expression. Break-points of the reciprocal chromosomes from chromosome 14 were identified in five of these cases: 1q23, 6q23- q25, 7p15, 8q11, and 12q13. Of the four mixed-lineage cases that were tested, none showed rearrangement of the immunoglobulin heavy chain (IgH) gene. This suggests that the 14q32 breakpoint does not involve the IgH gene and that an unidentified important gene may reside on 14q32.

scholarly journals 14q32 translocations are associated with mixed-lineage expression in childhood acute leukemia

Blood ◽  
1990 ◽  
Vol 76 (1) ◽  
pp. 150-156 ◽  
Author(s):  
Y Hayashi ◽  
CH Pui ◽  
FG Behm ◽  
AH Fuchs ◽  
SC Raimondi ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Lymphoblastic Leukemia ◽  
Antigen Expression ◽  
Leukemic Cells ◽  
Entire Cohort ◽  
Break Points ◽  
Acute Nonlymphoblastic Leukemia ◽  
B Lineage ◽  
Childhood Acute Leukemia ◽  
14Q32 Translocation

Abstract The frequency and characteristics of childhood acute leukemia with a 14q32 translocation [other than the t(8;14)(q24;q32)] were determined in 335 cases of newly diagnosed acute lymphoblastic leukemia (ALL) and 105 cases of acute nonlymphoblastic leukemia (ANLL). Ten children, representing 2.3% of the entire cohort, had this abnormality (1.5% of ALL patients and 4.8% of ANLL patients). By French-American-British (FAB) criteria, 4 cases were classified as L1, 1 as L2, 2 as M1, 1 as M2, and 2 as M5. Remarkably, mixed-lineage expression was found in 6 of these 10 cases, but in only 21 of the other 430 cases without a 14q32 translocation (P less than .001). Leukemic cells from 5 of these 6 cases (4 ANLL, and 1 ALL) coexpressed CD13, a myeloid-associated antigen, and CD2, a T-cell-associated antigen; blasts from the sixth case (ALL) coexpressed CD13 and CD19, a B-lineage-associated antigen. Thus, in addition to the well-described 11q23 translocations and t(9;22), 14q32 translocations also appear to be associated with mixed lineage antigen expression. Break-points of the reciprocal chromosomes from chromosome 14 were identified in five of these cases: 1q23, 6q23- q25, 7p15, 8q11, and 12q13. Of the four mixed-lineage cases that were tested, none showed rearrangement of the immunoglobulin heavy chain (IgH) gene. This suggests that the 14q32 breakpoint does not involve the IgH gene and that an unidentified important gene may reside on 14q32.

scholarly journals Human acute leukemia cell line with the t(4;11) chromosomal rearrangement exhibits B lineage and monocytic characteristics

Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 21-31 ◽  
Author(s):  
RC Stong ◽  
SJ Korsmeyer ◽  
JL Parkin ◽  
DC Arthur ◽  
JH Kersey
Keyword(s):  
Acute Leukemia ◽  
Cell Line ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Leukemic Cells ◽  
Leukemia Cell Line ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Immunoglobulin Gene ◽  
A Cell ◽  
B Lineage

Abstract A cell line, designated RS4;11, was established from the bone marrow of a patient in relapse with an acute leukemia that was characterized by the t(4;11) chromosomal abnormality. The cell line and the patient's fresh leukemic cells both had the t(4;11)(q21;q23) and an isochromosome for the long arm of No. 7. Morphologically, all cells were lymphoid in appearance. Ultrastructurally and cytochemically, approximately 30% of the cells possessed myeloid features. The cells were strongly positive for terminal deoxynucleotidyl transferase. They were HLA-DR positive and expressed surface antigens characteristic for B lineage cells, including those detected by anti-B4, BA-1, BA-2, and PI153/3. Immunoglobulin gene analysis revealed rearrangements of the heavy chain and kappa chain genes. The cells lacked the common acute lymphoblastic leukemia antigen and antigenic markers characteristic of T lineage cells. The cells reacted with the myeloid antibody 1G10 but not with other myeloid monoclonal antibodies. Treatment with 12-O-tetradecanoyl- phorbol-13-acetate induced a monocyte-like phenotype demonstrated by cytochemical, functional, immunologic, and electron microscopic studies. The expression of markers of both early lymphoid and early myeloid cells represents an unusual phenotype and suggests that RS4;11 represents a cell with dual lineage capabilities. To our knowledge, RS4;11 is the first cell line established from t(4;11)-associated acute leukemia.

Phase 1 and pharmacodynamic studies of G3139, a Bcl-2 antisense oligonucleotide, in combination with chemotherapy in refractory or relapsed acute leukemia

Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 425-432 ◽  
Author(s):  
Guido Marcucci ◽  
John C. Byrd ◽  
Guowei Dai ◽  
Marko I. Klisovic ◽  
Peter J. Kourlas ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Lymphoblastic Leukemia ◽  
Phase 1 ◽  
Salvage Chemotherapy ◽  
Leukemic Cells ◽  
Electrolyte Imbalance ◽  
Mrna Levels ◽  
Disease Response ◽  
Unfavorable Clinical Outcome ◽  
State Concentration

Overexpression of Bcl-2 is a potential mechanism for chemoresistance in acute leukemia and has been associated with unfavorable clinical outcome. We hypothesized that down-regulation of Bcl-2 would restore chemosensitivity in leukemic cells. To test this hypothesis, we performed a phase 1 study of G3139 (Genasense, Genta, Berkeley Heights, NJ), an 18-mer phosphorothioate Bcl-2 antisense, with fludarabine (FL), cytarabine (ARA-C), and granulocyte colony-stimulating factor (G-CSF) (FLAG) salvage chemotherapy in patients with refractory or relapsed acute leukemia. Twenty patients with refractory or relapsed acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) were enrolled. G3139 was delivered by continuous infusion on days 1 to 10. FLAG chemotherapy was administered on days 5 to 10. Common side effects of this combination included fever, nausea, emesis, electrolyte imbalance, and fluid retention that were not dose limiting. Plasma pharmacokinetics of G3139 demonstrated steady-state concentration (Css) within 24 hours. Of the 20 patients, 9 (45%) had disease response, 6 (5 AML, 1 ALL) with complete remission (CR) and 3 (2 AML and 1 ALL) with no evidence of disease but failure to recover normal neutrophil and/or platelet counts or to remain in remission for at least 30 days (incomplete remission). Bcl-2 mRNA levels were down-regulated in 9 of the 12 (75%) evaluable patients. This study demonstrates that G3139 can be administered safely with FLAG chemotherapy and down-regulate its target, Bcl-2. The encouraging clinical and laboratory results justify the current plans for a phase 3 study in previously untreated high-risk AML (ie, age at least 60 years).

scholarly journals Expression of the three myeloid cell-associated immunoglobulin G Fc receptors defined by murine monoclonal antibodies on normal bone marrow and acute leukemia cells

Blood ◽  
1989 ◽  
Vol 73 (7) ◽  
pp. 1951-1956
Author(s):  
ED Ball ◽  
J McDermott ◽  
JD Griffin ◽  
FR Davey ◽  
R Davis ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Monoclonal Antibodies ◽  
Acute Leukemia ◽  
Cell Sorting ◽  
Lymphoblastic Leukemia ◽  
Mononuclear Phagocytes ◽  
Leukemic Cells ◽  
Leukemia Cells ◽  
Normal Bone Marrow ◽  
Normal Bone

Monoclonal antibodies (MoAbs) have been prepared recently that recognize the three cell-surface receptors for the Fc portion of immunoglobulin (Ig), termed Fc gamma RI (MoAb 32.2), Fc gamma R II (MoAb IV-3), and Fc gamma R III (MoAb 3G8) that are expressed on selected subsets of non-T lymphocyte peripheral blood leukocytes. In the blood, Fc gamma R I is expressed exclusively on monocytes and macrophages, Fc gamma R II on granulocytes, mononuclear phagocytes, platelets, and B cells, and Fc gamma R III on granulocytes and natural killer (NK) cells. We have examined the expression of these molecules on normal bone marrow (BM) cells and on leukemia cells from the blood and/or BM in order to determine their normal ontogeny as well as their distribution on leukemic cells. BM was obtained from six normal volunteers and from 170 patients with newly diagnosed acute leukemia. Normal BM cells were found to express Fc gamma R I, II, and III with the following percentages: 40%, 58%, and 56%, respectively. Cell sorting revealed that both Fc gamma R I and Fc gamma R II were detectable on all subclasses of myeloid precursors as early as myeloblasts. Cell sorting experiments revealed that 66% of the granulocyte-monocyte colony-forming cells (CFU-GM) and 50% of erythroid burst-forming units (BFU-E) were Fc gamma R II positive with only 20% and 28%, respectively, of CFU-GM and BFU-E were Fc gamma R I positive. Acute myeloid leukemia (AML) cells expressed the three receptors with the following frequency (n = 146): Fc gamma R I, 58%; Fc gamma R II, 67%; and Fc gamma R III, 26% of patients. Despite the fact that Fc gamma R I is only expressed on monocytes among blood cells, AML cells without monocytoid differentiation (French-American-British [FAB]M1, M2, M3, M6) were sometimes positive for this receptor. However, Fc gamma R I was highly correlated with FAB M4 and M5 morphology (P less than .001). Fc gamma R II was also correlated with FAB M4 and M5 morphology (P = .003). Cells from 11 patients with acute lymphoblastic leukemia were negative for Fc gamma R I, but six cases were positive for Fc gamma R II and III (not the same patients). These studies demonstrate that Ig Fc gamma R are acquired during normal differentiation in the BM at or before the level of colony-forming units. In addition, we show that acute leukemia cells commonly express Fc gamma R.

scholarly journals The influence of a dosage regimen of dexamethasone on detection of normal B-cell precursors in the bone marrow of children with BCP-ALL at the end of induction therapy

2020 ◽  
Vol 19 (1) ◽  
pp. 53-57
Author(s):  
E. V. Mikhailova ◽  
T. Yu. Verzhbitskaya ◽  
J. V. Roumiantseva ◽  
O. I. Illarionova ◽  
A. A. Semchenkova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
B Cell ◽  
Induction Therapy ◽  
Therapy Group ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cells ◽  
Intermittent Therapy ◽  
Continuous Therapy ◽  
B Cell Precursors

Minimal residual disease (MRD) monitoring by flow cytometry at the end of induction therapy is one of the key ways of a prognosis assessment in patients with acute lymphoblastic leukemia (ALL). In B-cell precursor ALL (BCP–ALL), this method of MRD detection is complicated due to the immunophenotypic similarity between leukemic cells and normal B-cell precursors (BCPs). A decrease in intensity of induction therapy can lead to a more frequent appearance of normal BCPs in the bone marrow, which significantly complicates the MRD monitoring. Aim: to assess the incidence of normal BCPs in bone marrow on the 36th day of induction therapy with two different regimens of glucocorticoid (GC) administration according to ALL-MB 2015 protocol. This study was approved by the Independent Ethical Committee and the Academic Council of Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology, Immunology Ministry of Healthcare of Russian Federation. The study included 220 patients with BCP-ALL who were randomized to two types of GC-based induction therapy: a continuous administration of dexamethasone (n = 139) and an intermittent regimen with a 1-week dexamethasone therapy stop (n = 81). On the 36th day of induction therapy, MRD and normal BCPs were quantified in bone marrow samples by flow cytometry. On the 36th day of treatment, 43.2% of BCP(+) samples were established in the intermittent-therapy group, and 27.3% in the continuous-therapy group (p = 0.016). Comparison of the BCP level in BCP(+) samples revealed the more equitable distribution of BCPs at different developmental stages in the intermittent-therapy group, meanwhile mainly the immature BCPs in a quantity of less than 0.01% were found in the continuous-therapy group. Reduced-intensity induction therapy for patients with BCP-ALL leads to a noticeable increase of normal BCPs in bone marrow at the end of this treatment stage. A higher rate of BCP(+) bone marrow samples hinder the MRD detection due to the immunophenotypic similarity of BCPs and leukemic cells.

scholarly journals Expression of the three myeloid cell-associated immunoglobulin G Fc receptors defined by murine monoclonal antibodies on normal bone marrow and acute leukemia cells

Blood ◽  
1989 ◽  
Vol 73 (7) ◽  
pp. 1951-1956 ◽  
Author(s):  
ED Ball ◽  
J McDermott ◽  
JD Griffin ◽  
FR Davey ◽  
R Davis ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Monoclonal Antibodies ◽  
Acute Leukemia ◽  
Cell Sorting ◽  
Lymphoblastic Leukemia ◽  
Mononuclear Phagocytes ◽  
Leukemic Cells ◽  
Leukemia Cells ◽  
Normal Bone Marrow ◽  
Normal Bone

Abstract Monoclonal antibodies (MoAbs) have been prepared recently that recognize the three cell-surface receptors for the Fc portion of immunoglobulin (Ig), termed Fc gamma RI (MoAb 32.2), Fc gamma R II (MoAb IV-3), and Fc gamma R III (MoAb 3G8) that are expressed on selected subsets of non-T lymphocyte peripheral blood leukocytes. In the blood, Fc gamma R I is expressed exclusively on monocytes and macrophages, Fc gamma R II on granulocytes, mononuclear phagocytes, platelets, and B cells, and Fc gamma R III on granulocytes and natural killer (NK) cells. We have examined the expression of these molecules on normal bone marrow (BM) cells and on leukemia cells from the blood and/or BM in order to determine their normal ontogeny as well as their distribution on leukemic cells. BM was obtained from six normal volunteers and from 170 patients with newly diagnosed acute leukemia. Normal BM cells were found to express Fc gamma R I, II, and III with the following percentages: 40%, 58%, and 56%, respectively. Cell sorting revealed that both Fc gamma R I and Fc gamma R II were detectable on all subclasses of myeloid precursors as early as myeloblasts. Cell sorting experiments revealed that 66% of the granulocyte-monocyte colony-forming cells (CFU-GM) and 50% of erythroid burst-forming units (BFU-E) were Fc gamma R II positive with only 20% and 28%, respectively, of CFU-GM and BFU-E were Fc gamma R I positive. Acute myeloid leukemia (AML) cells expressed the three receptors with the following frequency (n = 146): Fc gamma R I, 58%; Fc gamma R II, 67%; and Fc gamma R III, 26% of patients. Despite the fact that Fc gamma R I is only expressed on monocytes among blood cells, AML cells without monocytoid differentiation (French-American-British [FAB]M1, M2, M3, M6) were sometimes positive for this receptor. However, Fc gamma R I was highly correlated with FAB M4 and M5 morphology (P less than .001). Fc gamma R II was also correlated with FAB M4 and M5 morphology (P = .003). Cells from 11 patients with acute lymphoblastic leukemia were negative for Fc gamma R I, but six cases were positive for Fc gamma R II and III (not the same patients). These studies demonstrate that Ig Fc gamma R are acquired during normal differentiation in the BM at or before the level of colony-forming units. In addition, we show that acute leukemia cells commonly express Fc gamma R.

scholarly journals CD2 antigen expression on leukemic cells as a predictor of event-free survival after chemotherapy for T-lineage acute lymphoblastic leukemia: a Children's Cancer Group study

Blood ◽  
1996 ◽  
Vol 88 (11) ◽  
pp. 4288-4295 ◽  
Author(s):  
FM Uckun ◽  
PG Steinherz ◽  
H Sather ◽  
M Trigg ◽  
D Arthur ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Lymphoblastic Leukemia ◽  
High Risk ◽  
Lymphoblastic Leukemia ◽  
Antigen Expression ◽  
Leukemic Cells ◽  
Event Free Survival ◽  
Free Survival ◽  
Cancer Group ◽  
Standard Risk

Abstract We examined the prognostic impact of CD2 antigen expression for 651 patients with T-lineage acute lymphoblastic leukemia (ALL), who were enrolled in front-line Childrens Cancer Group treatment studies between 1983 and 1994. There was a statistically significant correlation between the CD2 antigen positive leukemic cell content of bone marrow and probability of remaining in bone marrow remission, as well as overall event-free survival (EFS) (P = .0003 and P = .002, log-rank tests for linear trend). When compared with patients with the highest CD2 expression level (> 75% positivity), the life table relative event rate (RER) was 1.22 for patients with intermediate range CD2 expression level (30% to 75% positivity) and 1.81 for “CD2-negative” patients (< 30% positivity). At 6 years postdiagnosis, the EFS estimates for the three CD2 expression groups (low positivity to high positivity) were 52.8%, 65.5%, and 71.9%, respectively. CD2 expression remained a significant predictor of EFS after adjustment for the effects of other covariates by multivariate regression, with a RER of 1.47 for CD2- negative patients (P = .04). Analysis of T-lineage ALL patients shows a significant separation in EFS after adjustment for the National Cancer Institute (NCI) age and white blood cell (WBC) criteria for standard and high-risk ALL (P = .002, RER = 1.67). The determination of CD2 expression on leukemic cells helped identify patients with the better and poorer prognoses in both of these risk group subsets. For standard risk T-lineage ALL, CD2-negative patients had a worse outcome (P = .0007, RER = 2.92) with an estimated 5-year EFS of 55.9% as compared with 78.3% for the CD2-positive patients. Thus, CD2 negativity in standard risk T-lineage ALL identified a group of patients who had a worse outcome than high-risk T-lineage ALL patients who were CD2 positive. The percentage of CD2 antigen positive leukemic cells from T- lineage ALL patients is a powerful predictor of EFS after chemotherapy. This prognostic relationship is the first instance in which a biological marker in T-lineage ALL has been unequivocally linked to treatment outcome.

Molecular and Phenotypic Analysis of Philadelphia Chromosome-Positive Bilineage Leukemia: Possibility of a Lineage Switch from T-Lymphoid Leukemia Progenitor to Myeloid Cells Via PU.1 Expression.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4362-4362
Author(s):  
Kazuhiro Nishii ◽  
Fumihiko Monma ◽  
Felipe Lorenzo ◽  
Naoyuki Katayama ◽  
Hiroshi Shiku
Keyword(s):  
T Cell ◽  
Fusion Gene ◽  
Lymphoblastic Leukemia ◽  
Philadelphia Chromosome ◽  
Leukemic Cells ◽  
Nucleotide Sequencing ◽  
Phenotypic Analysis ◽  
Lymphoid Leukemia ◽  
Lineage Switch ◽  
Philadelphia Chromosome Positive

Abstract The occurrence of acute bilineage leukemia is thought to be the malignant transformation of a myeloid or lymphoid leukemic progenitor with the potential to differentiate into the other lineages; however, the mechanisms of this lineage switch are not well understood. Here, we show the extremely rare case of adult Philadelphia chromosome positive acute bilineage leukemia, characterized by T-cell acute lymphoblastic leukemia, CD7+CD5+CD14−, and acute myelomonocytic leukemia, CD7−CD5−CD14+. Chromosome analysis showed 46,XY,del(7)(p11.2),t(9;22)(q34;q11.2) in all metaphase and leukemic cells expressed a minor BCR/ABL chimeric gene. When the CD5+CD14− and CD5−CD14+ cells were sorted, a fusion gene of BCR/ABL and a same clonal rearranged band of a T-cell receptor (TCR) gene were detected in both populations. Nucleotide sequencing of the TCRg gene revealed the clonal rearrangement of the V8-JGT2 complex in both populations. Over-expression of PU.1, which plays a fundamental role in myelomonocyte development was found in the sorted CD34+CD7+ and CD5−CD14+, but not CD5+CD14− cells. These results suggest that leukemic progenitor cells in the T-lineage with del(7),t(9;22) chromosome have the potential to differentiate into myeloid lineage and enforced PU.1 expression may contribute in part of this phenomenon. Studies of bilineage leukemia will be important for the understanding of lineage commitment and switch in hematopoietic cells.

Clinical Relevance of Complex Chromosomal Aberrations in Bone Marrow Cells of 107 Children with ETV6/RUNX1 Positive Acute Lymphoblastic Leukemia (ALL).

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2278-2278 ◽  
Author(s):  
Zuzana Zemanova ◽  
Kyra Michalova ◽  
Libuse Babicka ◽  
Lenka Pavlistova ◽  
Marie Jarosova ◽  
...  
Keyword(s):  
Chromosomal Aberrations ◽  
Bone Marrow Cells ◽  
Fusion Gene ◽  
Lymphoblastic Leukemia ◽  
Chromosomal Rearrangements ◽  
Chromosome 21 ◽  
Leukemic Cells ◽  
Rt Pcr ◽  
Cryptic Translocation ◽  
Complex Chromosomal Rearrangements

Abstract Cryptic translocation t(12;21)(p13;q22) which give origin to the ETV6/RUNX1 hybrid gene can be found by I-FISH in approximately 20–25% of children with B precursor ALL as the most frequent specific aberration. This translocation is generally associated with good outcome. Despite of its favorable prognostic value, late relapses may occur within this group of patients. One of the reasons could be the high instability of the genome of leukemic cells, which is manifested at the chromosomal level by additional aberrations and/or complex chromosomal rearrangements. The aim of the study was to evaluate the significance of the additional chromosomal aberrations for prognosis of children with ETV6/RUNX1 positive ALL. For the assessment of ETV6/RUNX1 fusion gene RT-PCR and/or double target interphase FISH with locus-specific probe (Abbott-Vysis, Des Plaines, Illinois, USA) were used (200 interphase nuclei analyzed, cut-off level 2.5% tested on controls, standard deviation ≤0.5%). Karyotypes were analyzed by conventional and molecular cytogenetic methods. Structural and/or complex chromosomal aberration were verified by FISH with whole chromosome painting probes (Cambio, Cambridge, UK) and/or by mFISH with the "24XCyte" probe kit (MetaSystems GmbH, Altlussheim, Germany). We performed prospective and retrospective study of 107 children with ALL and ETV6/RUNX1 fusion gene detected by RT-PCR and/or I-FISH. Patients were diagnosed between 1995 and 2006, age ranged between 15 months and 16.9 years (median 4.2 years). Relapse appeared in 19 children (17.8%), four of them died. In 64 children (59.8%) we found besides t(12;21)(p13;q22) additional chromosomal aberrations, the most frequently trisomy or tetrasomy of chromosome 21 (20 cases), deletion of non-translocated ETV6 allele (24 cases), deletion of 6q (7 cases) and/or rearrangements of the long arm of chromosome X (6 cases). Complex karyotypes were identified in 38 children (35.5%). In twelve of them variant translocations of chromosomes 12 and 21 with other partners were observed. Event-free survival (EFS) was significantly shorter in patients with additional structural and/or complex aberrations in ETV6/RUNX1 positive cells (p=0.01). In our cohort complex karyotypes indicated poor prognosis. Finding of complex chromosomal aberrations in leukemic cells is accompanied by higher risk of relapse even in those cases where the prognostically positive aberration is primarily present.

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