INCIDENCE AND MAIN CHARACTERISTICS OF T(12;22)(P13;Q12)/MN1-ETV6-POSITIVE ADULT BULGARIAN ACUTE MYELOID LEUKEMIA PATIENTS: A SINGLE INSTITUTION EXPERIENCE
(Abstract release date: 05/19/16)
EHA Library. Balatzenko G. 06/09/16; 134551; PB1651
Dr. Gueorgui Balatzenko
Contributions
Contributions
Abstract
Abstract: PB1651
Type: Publication Only
Background
Translocation t(12;22)(p13;q12) is a recurrent, but rare genetic abnormality in acute myeloid leukemia (AML). To our knowledge, only 14 cases of t(12;22)-positive AML have been published so far. This translocation results in the MN1-ETV6 fusion gene formation, however, in only 5 of the reported t(12;22)-positive AMLs, the presence of MN1-ETV6 fusion gene was confirmed molecularly [1;2;3]. Due to the rareness of the disease data about the clinical and laboratory features of t(12;22)-positive AML patients are still limited.
Aims
To determine the incidence and the main characteristics of t(12;22)-positive AML.
Methods
Bone marrow aspirates of 645 adult AML patient were tested in the Laboratory of Cytogenetics and Molecular Biology of the National Specialized Hospital for Active Treatment of Hematological Diseases – Sofia during a 10-years period. Successful karyotypes were obtained in 555 patients (86%). In all cases with t(12;22), the presence of MN1-ETV6 rearrangement was additionally tested by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). The AML diagnosis and subclassification were performed according to the World Health Organization Classification criteria (2008).
Results
Overall, t(12;22) was detected by conventional cytogenetics in three patients (0.54%). In all of them the translocation was identified as a sole chromosome abnormality and the MN1-ETV6 fusion was confirmed by FISH and RT-PCR. None of the patients was positive for BCR-ABL1, CBFb-MYH11, AML1-ETO, FLT3-ITD, JAK2 V617F, and NPM1 mutations. Two of the patients were male and one was female, aged 60, 65 and 71 years, respectively. White blood cell counts varied from 4.6x109/L to 77.5x109/L, platelet counts from 14x109/L to 104x109/L, and hemoglobin from 81 g/L to 125 g/L. Morphology was myelomonocytic in all patients, associated with granulocytic dysplasia in one of the cases and presented as a hypoplastic leukemia in another. Bone marrow blasts accounted for 58%>88%. Flow cytometry revealed CD34 positive expression and aberrant myelomonocytic phenotypes in all three patients, with CD56 positive and CD4 positive immune labeling in 2 patients each. Aberrant expression of other lymphoid-associated antigens (CD7/CD19) was also detected in one case. No splenomegaly was found in all of the patients, while mild liver enlargement was observed in one of them. Two of patients received conventional cytarabine/antracycline-based induction therapy. Unfortunately, early death occurred in both cases. The third patient refused chemotherapy and was lost of follow up.
Conclusion
Our study confirmed the low incidence of t(12;22)/MN1-ETV6-positive AML. Though heterogeneous in terms of clinical and laboratory presentation, the reported patients were characterized by absence of additional chromosomal aberrations, aberrant myelomonocytic phenotype and a high induction-induced death rate.Acknowledgements: This study was partially supported by the National Science Fund, Ministry of Education, Youth and Science.References: (1) Buijs A, et al. Oncogene. 1995;10(8):1511-9; (2) Vieira L, et al., Br J Haematol. 2000;110(1):238-9; (3) Nofrini V, et al., Leuk Res. 2011;35(7):e123-6.
Session topic: E-poster
Keyword(s): Acute myeloid leukemia, Chromosomal translocation, Cytogenetics
Type: Publication Only
Background
Translocation t(12;22)(p13;q12) is a recurrent, but rare genetic abnormality in acute myeloid leukemia (AML). To our knowledge, only 14 cases of t(12;22)-positive AML have been published so far. This translocation results in the MN1-ETV6 fusion gene formation, however, in only 5 of the reported t(12;22)-positive AMLs, the presence of MN1-ETV6 fusion gene was confirmed molecularly [1;2;3]. Due to the rareness of the disease data about the clinical and laboratory features of t(12;22)-positive AML patients are still limited.
Aims
To determine the incidence and the main characteristics of t(12;22)-positive AML.
Methods
Bone marrow aspirates of 645 adult AML patient were tested in the Laboratory of Cytogenetics and Molecular Biology of the National Specialized Hospital for Active Treatment of Hematological Diseases – Sofia during a 10-years period. Successful karyotypes were obtained in 555 patients (86%). In all cases with t(12;22), the presence of MN1-ETV6 rearrangement was additionally tested by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). The AML diagnosis and subclassification were performed according to the World Health Organization Classification criteria (2008).
Results
Overall, t(12;22) was detected by conventional cytogenetics in three patients (0.54%). In all of them the translocation was identified as a sole chromosome abnormality and the MN1-ETV6 fusion was confirmed by FISH and RT-PCR. None of the patients was positive for BCR-ABL1, CBFb-MYH11, AML1-ETO, FLT3-ITD, JAK2 V617F, and NPM1 mutations. Two of the patients were male and one was female, aged 60, 65 and 71 years, respectively. White blood cell counts varied from 4.6x109/L to 77.5x109/L, platelet counts from 14x109/L to 104x109/L, and hemoglobin from 81 g/L to 125 g/L. Morphology was myelomonocytic in all patients, associated with granulocytic dysplasia in one of the cases and presented as a hypoplastic leukemia in another. Bone marrow blasts accounted for 58%>88%. Flow cytometry revealed CD34 positive expression and aberrant myelomonocytic phenotypes in all three patients, with CD56 positive and CD4 positive immune labeling in 2 patients each. Aberrant expression of other lymphoid-associated antigens (CD7/CD19) was also detected in one case. No splenomegaly was found in all of the patients, while mild liver enlargement was observed in one of them. Two of patients received conventional cytarabine/antracycline-based induction therapy. Unfortunately, early death occurred in both cases. The third patient refused chemotherapy and was lost of follow up.
Conclusion
Our study confirmed the low incidence of t(12;22)/MN1-ETV6-positive AML. Though heterogeneous in terms of clinical and laboratory presentation, the reported patients were characterized by absence of additional chromosomal aberrations, aberrant myelomonocytic phenotype and a high induction-induced death rate.Acknowledgements: This study was partially supported by the National Science Fund, Ministry of Education, Youth and Science.References: (1) Buijs A, et al. Oncogene. 1995;10(8):1511-9; (2) Vieira L, et al., Br J Haematol. 2000;110(1):238-9; (3) Nofrini V, et al., Leuk Res. 2011;35(7):e123-6.
Session topic: E-poster
Keyword(s): Acute myeloid leukemia, Chromosomal translocation, Cytogenetics
Abstract: PB1651
Type: Publication Only
Background
Translocation t(12;22)(p13;q12) is a recurrent, but rare genetic abnormality in acute myeloid leukemia (AML). To our knowledge, only 14 cases of t(12;22)-positive AML have been published so far. This translocation results in the MN1-ETV6 fusion gene formation, however, in only 5 of the reported t(12;22)-positive AMLs, the presence of MN1-ETV6 fusion gene was confirmed molecularly [1;2;3]. Due to the rareness of the disease data about the clinical and laboratory features of t(12;22)-positive AML patients are still limited.
Aims
To determine the incidence and the main characteristics of t(12;22)-positive AML.
Methods
Bone marrow aspirates of 645 adult AML patient were tested in the Laboratory of Cytogenetics and Molecular Biology of the National Specialized Hospital for Active Treatment of Hematological Diseases – Sofia during a 10-years period. Successful karyotypes were obtained in 555 patients (86%). In all cases with t(12;22), the presence of MN1-ETV6 rearrangement was additionally tested by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). The AML diagnosis and subclassification were performed according to the World Health Organization Classification criteria (2008).
Results
Overall, t(12;22) was detected by conventional cytogenetics in three patients (0.54%). In all of them the translocation was identified as a sole chromosome abnormality and the MN1-ETV6 fusion was confirmed by FISH and RT-PCR. None of the patients was positive for BCR-ABL1, CBFb-MYH11, AML1-ETO, FLT3-ITD, JAK2 V617F, and NPM1 mutations. Two of the patients were male and one was female, aged 60, 65 and 71 years, respectively. White blood cell counts varied from 4.6x109/L to 77.5x109/L, platelet counts from 14x109/L to 104x109/L, and hemoglobin from 81 g/L to 125 g/L. Morphology was myelomonocytic in all patients, associated with granulocytic dysplasia in one of the cases and presented as a hypoplastic leukemia in another. Bone marrow blasts accounted for 58%>88%. Flow cytometry revealed CD34 positive expression and aberrant myelomonocytic phenotypes in all three patients, with CD56 positive and CD4 positive immune labeling in 2 patients each. Aberrant expression of other lymphoid-associated antigens (CD7/CD19) was also detected in one case. No splenomegaly was found in all of the patients, while mild liver enlargement was observed in one of them. Two of patients received conventional cytarabine/antracycline-based induction therapy. Unfortunately, early death occurred in both cases. The third patient refused chemotherapy and was lost of follow up.
Conclusion
Our study confirmed the low incidence of t(12;22)/MN1-ETV6-positive AML. Though heterogeneous in terms of clinical and laboratory presentation, the reported patients were characterized by absence of additional chromosomal aberrations, aberrant myelomonocytic phenotype and a high induction-induced death rate.Acknowledgements: This study was partially supported by the National Science Fund, Ministry of Education, Youth and Science.References: (1) Buijs A, et al. Oncogene. 1995;10(8):1511-9; (2) Vieira L, et al., Br J Haematol. 2000;110(1):238-9; (3) Nofrini V, et al., Leuk Res. 2011;35(7):e123-6.
Session topic: E-poster
Keyword(s): Acute myeloid leukemia, Chromosomal translocation, Cytogenetics
Type: Publication Only
Background
Translocation t(12;22)(p13;q12) is a recurrent, but rare genetic abnormality in acute myeloid leukemia (AML). To our knowledge, only 14 cases of t(12;22)-positive AML have been published so far. This translocation results in the MN1-ETV6 fusion gene formation, however, in only 5 of the reported t(12;22)-positive AMLs, the presence of MN1-ETV6 fusion gene was confirmed molecularly [1;2;3]. Due to the rareness of the disease data about the clinical and laboratory features of t(12;22)-positive AML patients are still limited.
Aims
To determine the incidence and the main characteristics of t(12;22)-positive AML.
Methods
Bone marrow aspirates of 645 adult AML patient were tested in the Laboratory of Cytogenetics and Molecular Biology of the National Specialized Hospital for Active Treatment of Hematological Diseases – Sofia during a 10-years period. Successful karyotypes were obtained in 555 patients (86%). In all cases with t(12;22), the presence of MN1-ETV6 rearrangement was additionally tested by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). The AML diagnosis and subclassification were performed according to the World Health Organization Classification criteria (2008).
Results
Overall, t(12;22) was detected by conventional cytogenetics in three patients (0.54%). In all of them the translocation was identified as a sole chromosome abnormality and the MN1-ETV6 fusion was confirmed by FISH and RT-PCR. None of the patients was positive for BCR-ABL1, CBFb-MYH11, AML1-ETO, FLT3-ITD, JAK2 V617F, and NPM1 mutations. Two of the patients were male and one was female, aged 60, 65 and 71 years, respectively. White blood cell counts varied from 4.6x109/L to 77.5x109/L, platelet counts from 14x109/L to 104x109/L, and hemoglobin from 81 g/L to 125 g/L. Morphology was myelomonocytic in all patients, associated with granulocytic dysplasia in one of the cases and presented as a hypoplastic leukemia in another. Bone marrow blasts accounted for 58%>88%. Flow cytometry revealed CD34 positive expression and aberrant myelomonocytic phenotypes in all three patients, with CD56 positive and CD4 positive immune labeling in 2 patients each. Aberrant expression of other lymphoid-associated antigens (CD7/CD19) was also detected in one case. No splenomegaly was found in all of the patients, while mild liver enlargement was observed in one of them. Two of patients received conventional cytarabine/antracycline-based induction therapy. Unfortunately, early death occurred in both cases. The third patient refused chemotherapy and was lost of follow up.
Conclusion
Our study confirmed the low incidence of t(12;22)/MN1-ETV6-positive AML. Though heterogeneous in terms of clinical and laboratory presentation, the reported patients were characterized by absence of additional chromosomal aberrations, aberrant myelomonocytic phenotype and a high induction-induced death rate.Acknowledgements: This study was partially supported by the National Science Fund, Ministry of Education, Youth and Science.References: (1) Buijs A, et al. Oncogene. 1995;10(8):1511-9; (2) Vieira L, et al., Br J Haematol. 2000;110(1):238-9; (3) Nofrini V, et al., Leuk Res. 2011;35(7):e123-6.
Session topic: E-poster
Keyword(s): Acute myeloid leukemia, Chromosomal translocation, Cytogenetics
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