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Dicentric (17;20)(p11.2;q11.2): an uncommon cytogenetic abnormality in myeloid malignancies
Cancer Genetics and Cytogenetics 170 (2006) 61e64
Short communication
Dicentric (17;20)(p11.2;q11.2): an uncommon cytogenetic abnormality in myeloid malignancies Carlos A. Tiradoa,*, Aurelia M. Meloni-Ehriga, Eian Wallenhorsta, Kristine Burksa, Jay Scheerlea, Maurice Morillona, JoAnn C. Kellya, Deborah Heritagea, Alexander Spirab, Calvin D. Crofta, Lewis Glasserc, James N. Buterad, Philip Mowreya a
Laboratory of Cytogenetics, Quest Diagnostics Nichols Institute, 14225 Newbrook Drive, Chantilly, VA 20151 b Department of Hematology, Oncology, Inova Fairfax Hospital, Fairfax, VA Departments of cPathology and dMedicine, Brown Medical School, Providence, RI Received 3 February 2006; received in revised form 5 April 2006; accepted 18 April 2006
Abstract
We report on two patients with myeloid disorders and complex karyotypes including a dicentric chromosome, dic(17;20)(p11.2;q11.2), resulting in the loss of most of 17p and 20q. The presence of the centromeres of chromosomes 17 and 20 in the dic(17;20), as well as the loss of TP53, were confirmed by fluorescence in situ hybridization. Deletions of 17p and 20q are recurrent abnormalities in hematologic disorders, particularly myelodysplastic syndrome and acute myeloid leukemia). However, a dic(17;20) is an uncommon finding. According to the few reports in the literature, dic(17;20) is associated with an unfavorable prognosis. The key mechanism might be the loss of TP53 as well as other tumor suppressor genes in 20q that may have a critical role in tumor genesis. Ó 2006 Elsevier Inc. All rights reserved.
1. Introduction
2. Clinical presentation
Deletions of 17p and 20q have been observed in approximately 4 and 5% of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cases, respectively. The less common dic(17;20)(p11.2;q11.2), however, has been reported in only few cases of MDS and AML [1]. Here, we report on two patients, a 47-year-old male with AML and a 74 year-old female with therapy-related MDS. These patients showed complex karyotypes that had in common a dic(17;20)(p11.2;q11.2), leading to loss of most of 17p and 20q. In addition to routine chromosome analysis, fluorescence in situ hybridization (FISH) was also performed using centromeric probes specific for chromosomes 17 and 20. The dic(17;20) was visible in both interphase and metaphase cells. The loss of TP53 at 17p as a result of the dic(17;20) was confirmed using the p53 FISH probe. It has been reported that dic(17;20), especially in the presence of other chromosomal abnormalities, is associated with an unfavorable prognosis [1,2].
2.1. Case 1
* Corresponding author. Tel.: (703) 802-6900, x5328; fax: (703) 802-7103. E-mail address: [email protected] (C.A. Tirado). 0165-4608/06/$ e see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.cancergencyto.2006.04.013
This patient is a 47-year-old male who presented with pancytopenia. Examination of his peripheral blood showed a white blood count (WBC) of 6103/mL, hemoglobin of 6.0g/dL, and a platelet count of 20103/mL. There were no circulating blasts in the peripheral blood. On the other hand, his bone marrow was hypercellular (75% cellularity), with 58% blasts. Immunophenotyping showed that the blasts were of myeloid origin, expressing myeloperoxidase as well as the markers CD13, CD33, CD64, CD34, and CD117. The diagnosis of AML was made at that time. This patient received induction chemotherapy, but on day 14, the marrow still showed persistence of the AML. He subsequently received additional rounds of the initial chemotherapy.
2.2. Case 2 This patient is a 74-year-old female with a history of lymphoma since 1980, for which she received chemotherapy and radiation. Her recent peripheral blood findings included a WBC of approximately 3.5103/mL, a normal platelet
C.A. Tirado et al. / Cancer Genetics and Cytogenetics 170 (2006) 61e64
62
Fig. 1. G-banded karyogram of patient 1: 45,XY,-6,-11,add(12)(q13),dic(17;20)(p11.2;q11.2),-18,þmar1x2.
count, a hematocrit of 30%, and a mean corpuscular volume of 103, suggestive of MDS. 3. Materials and methods 3.1. Chromosome analysis The bone marrow samples from the two patients were processed using standard cytogenetic techniques. Briefly, two unstimulated cultures were set up in RPMI 1640 medium enriched with 20% fetal calf serum, Grant Cell Tumor conditioned medium, L-glutamine, and antibiotics (penicillin and streptomycin). The cells were cultured for 24 and 48 hours in a humidified environment with 5% CO2 in a 37 C incubator until harvest.
Fig. 2. Partial G-banded karyogram and ideogram of patient 2 showing the dic(17;20)(p11.2;q11.2).
Before harvest, the bone marrow cultures were treated with Colcemid (25 mL) for 16e18 hours. After the Colcemid treatment, the cells obtained from both cultures were exposed to hypotonic solution (0.075 mol/L KCl), fixed with methanol/acetic acid (3:1), spread onto a slide, and G-banded using trypsin and Giemsa stain. The slides were prepared and stained using G-banding (Giemsa-Trypsin-Wright), and 20 metaphases were analyzed from each sample. The cells were imaged and the karyograms were prepared with the Cytovision Computer-Assisted Karyotyping System (Applied Imaging, Santa Clara, CA). These karyograms were described according to the International System for Human Cytogenetics Nomenclature (ISCN 2005) [3]. 3.2. FISH analysis The FISH procedure was carried out following the manufacturer’s guidelines with minor modifications. FISH with the MLL probe was performed to investigate the status of the MLL gene. The loss of TP53 was investigated using the p53 probe. For confirmation of the dic(17;20), FISH was performed using the centromeric probes for chromosomes 17 and 20. All probes were purchased from Vysis, Inc. (Downers Grove, IL). After overnight hybridization and subsequent washing, the slides were analyzed using a BX51 Olympus fluorescence microscope (Exfo America; Olympus, Richardson, TX). Selected images were captured using a CCD camera (Sensys; Photometrics, Tucson, AZ) and Cytovision (Applied Imaging).
C.A. Tirado et al. / Cancer Genetics and Cytogenetics 170 (2006) 61e64
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Fig. 3. FISH image showing loss of one copy of the TP53 gene. The metaphase appears stained in blue [40 ,6-diamidino-2-phenylindole (DAPI counterstain)] with only one red signal for the p53 probe.
4. Results 4.1. Chromosome analysis Conventional chromosome analysis of the two patients’ bone marrow cells showed complex karyotypes, which
included a dic(17;20). The karyotype of patient 1 was: 43~45,XY,-6,-11,add(12)(q13),dic(17;20)(p11.2;q11.2),-18, þmar1x2[cp10]/46,XY[10]. The karyotype of patient 2 was: 45,XX,del(5)(q13q33),dic(17;20)(p11.2;q11.2)[cp3]/ 46,XX[17] (Figs. 1 and 2).
Fig. 4. FISH image of a metaphase showing a normal copy of chromosomes 17 and 20 as well as the dic(17;20). The metaphase appears stained in blue (DAPI counterstain). Red signal, chromosome 20 centromere; green signal: chromosome 9 centromere. The dic(17;10) shows both centromeres.
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C.A. Tirado et al. / Cancer Genetics and Cytogenetics 170 (2006) 61e64
4.2. FISH analysis FISH studies showed evidence of a dic(17;20), since both centromeres were located on the same derivative chromosome. The abnormality was evident in both interphase and metaphase cells (Fig. 3). FISH with the p53 probe revealed the loss of TP53 (Fig. 4). FISH using the MLL probe also revealed three MLL signals, one on the normal chromosome 11 and the other two on each of the two marker chromosomes.
5. Discussion Deletions of 17p and 20q are recurrent in hematologic disorders including MDS, myeloproliferative disorders, and AML. Deletion of 17p has been associated with loss of granulocyte maturation, which correlates with progression of the disease, poor response to chemotherapy, and adverse clinical outcome [4e8]. Rearrangements of chromosome 17 are frequent and include balanced and unbalanced rearrangements. Among the unbalanced rearrangements, simple deletions of 17p and the presence of i(17)(q10) have been reported more frequently [7,8]. However, the dic(17;20) described here is an uncommon finding and only few reports can be found in the literature [1,3]. One abnormality that has been observed in association with dic(17;20) is del(5q), which supports an MDS origin of the malignancy in patient 2 [3].
The key event in the dic(17;20) might be the deletion of the tumor suppressor gene TP53 as well as other tumor suppressor genes in 20q that may have a critical role in tumor genesis [3].
References [1] Patsouris C, Michael P, Campbell L. A new nonrandom unbalanced t(17;20) in myeloid malignancies. Cancer Genet Cytogenet 2002; 138:32e7. [2] Watson N, Dunlop L, Robson L, Sharma P, Smith A. 17pe syndrome arising from a novel dicentric translocation in a patient with acute myeloid leukemia. Cancer Genet Cytogenet 2000;118:159e62. [3] ISCN. An international system for human cytogenetics nomenclature. In: Shaffer LG, Tommerup N, editors. Basel: S. Karger, 2005. [4] Fenaux P, Morel P, Lai JL. Cytogenetics of myelodysplastic syndromes. Semin Hematol 1996;33:127e38. [5] Soenen V, Prendhomme C, Roumier C, Daudignon A, Lai JF, Fenaux P. 17p deletion in acute myeloid leukemia and myelodysplastic syndrome. Analysis of breakpoints and deleted segments by fluorescence in situ. Blood 1998;91:1008e15. [6] Pederson B, Kerndrup G. Granulocyte maturation and the chromosome deletion 17p- in primary myelodysplastic syndrome. Acta Haematol 1990;84:77e81. [7] Jonveaux P, Feanux P, Pignon JM, Lai JL, Quiquandon I, Kerchaert JP, Loucheux-Lefebvre MH, Goosens M, Bauters F, Berger R. Mutation in the p53 gene in myelodysplastic syndrome. Oncogene 1991;6:2243. [8] Jary L, Mossafa H, Fourcade C, Genet P, Pulik M, Flandrin G. The 17pe syndrome: a distinct myelodysplastic syndrome entity? Leuk Lymphoma 1982;25:163.
Short communication
Dicentric (17;20)(p11.2;q11.2): an uncommon cytogenetic abnormality in myeloid malignancies Carlos A. Tiradoa,*, Aurelia M. Meloni-Ehriga, Eian Wallenhorsta, Kristine Burksa, Jay Scheerlea, Maurice Morillona, JoAnn C. Kellya, Deborah Heritagea, Alexander Spirab, Calvin D. Crofta, Lewis Glasserc, James N. Buterad, Philip Mowreya a
Laboratory of Cytogenetics, Quest Diagnostics Nichols Institute, 14225 Newbrook Drive, Chantilly, VA 20151 b Department of Hematology, Oncology, Inova Fairfax Hospital, Fairfax, VA Departments of cPathology and dMedicine, Brown Medical School, Providence, RI Received 3 February 2006; received in revised form 5 April 2006; accepted 18 April 2006
Abstract
We report on two patients with myeloid disorders and complex karyotypes including a dicentric chromosome, dic(17;20)(p11.2;q11.2), resulting in the loss of most of 17p and 20q. The presence of the centromeres of chromosomes 17 and 20 in the dic(17;20), as well as the loss of TP53, were confirmed by fluorescence in situ hybridization. Deletions of 17p and 20q are recurrent abnormalities in hematologic disorders, particularly myelodysplastic syndrome and acute myeloid leukemia). However, a dic(17;20) is an uncommon finding. According to the few reports in the literature, dic(17;20) is associated with an unfavorable prognosis. The key mechanism might be the loss of TP53 as well as other tumor suppressor genes in 20q that may have a critical role in tumor genesis. Ó 2006 Elsevier Inc. All rights reserved.
1. Introduction
2. Clinical presentation
Deletions of 17p and 20q have been observed in approximately 4 and 5% of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cases, respectively. The less common dic(17;20)(p11.2;q11.2), however, has been reported in only few cases of MDS and AML [1]. Here, we report on two patients, a 47-year-old male with AML and a 74 year-old female with therapy-related MDS. These patients showed complex karyotypes that had in common a dic(17;20)(p11.2;q11.2), leading to loss of most of 17p and 20q. In addition to routine chromosome analysis, fluorescence in situ hybridization (FISH) was also performed using centromeric probes specific for chromosomes 17 and 20. The dic(17;20) was visible in both interphase and metaphase cells. The loss of TP53 at 17p as a result of the dic(17;20) was confirmed using the p53 FISH probe. It has been reported that dic(17;20), especially in the presence of other chromosomal abnormalities, is associated with an unfavorable prognosis [1,2].
2.1. Case 1
* Corresponding author. Tel.: (703) 802-6900, x5328; fax: (703) 802-7103. E-mail address: [email protected] (C.A. Tirado). 0165-4608/06/$ e see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.cancergencyto.2006.04.013
This patient is a 47-year-old male who presented with pancytopenia. Examination of his peripheral blood showed a white blood count (WBC) of 6103/mL, hemoglobin of 6.0g/dL, and a platelet count of 20103/mL. There were no circulating blasts in the peripheral blood. On the other hand, his bone marrow was hypercellular (75% cellularity), with 58% blasts. Immunophenotyping showed that the blasts were of myeloid origin, expressing myeloperoxidase as well as the markers CD13, CD33, CD64, CD34, and CD117. The diagnosis of AML was made at that time. This patient received induction chemotherapy, but on day 14, the marrow still showed persistence of the AML. He subsequently received additional rounds of the initial chemotherapy.
2.2. Case 2 This patient is a 74-year-old female with a history of lymphoma since 1980, for which she received chemotherapy and radiation. Her recent peripheral blood findings included a WBC of approximately 3.5103/mL, a normal platelet
C.A. Tirado et al. / Cancer Genetics and Cytogenetics 170 (2006) 61e64
62
Fig. 1. G-banded karyogram of patient 1: 45,XY,-6,-11,add(12)(q13),dic(17;20)(p11.2;q11.2),-18,þmar1x2.
count, a hematocrit of 30%, and a mean corpuscular volume of 103, suggestive of MDS. 3. Materials and methods 3.1. Chromosome analysis The bone marrow samples from the two patients were processed using standard cytogenetic techniques. Briefly, two unstimulated cultures were set up in RPMI 1640 medium enriched with 20% fetal calf serum, Grant Cell Tumor conditioned medium, L-glutamine, and antibiotics (penicillin and streptomycin). The cells were cultured for 24 and 48 hours in a humidified environment with 5% CO2 in a 37 C incubator until harvest.
Fig. 2. Partial G-banded karyogram and ideogram of patient 2 showing the dic(17;20)(p11.2;q11.2).
Before harvest, the bone marrow cultures were treated with Colcemid (25 mL) for 16e18 hours. After the Colcemid treatment, the cells obtained from both cultures were exposed to hypotonic solution (0.075 mol/L KCl), fixed with methanol/acetic acid (3:1), spread onto a slide, and G-banded using trypsin and Giemsa stain. The slides were prepared and stained using G-banding (Giemsa-Trypsin-Wright), and 20 metaphases were analyzed from each sample. The cells were imaged and the karyograms were prepared with the Cytovision Computer-Assisted Karyotyping System (Applied Imaging, Santa Clara, CA). These karyograms were described according to the International System for Human Cytogenetics Nomenclature (ISCN 2005) [3]. 3.2. FISH analysis The FISH procedure was carried out following the manufacturer’s guidelines with minor modifications. FISH with the MLL probe was performed to investigate the status of the MLL gene. The loss of TP53 was investigated using the p53 probe. For confirmation of the dic(17;20), FISH was performed using the centromeric probes for chromosomes 17 and 20. All probes were purchased from Vysis, Inc. (Downers Grove, IL). After overnight hybridization and subsequent washing, the slides were analyzed using a BX51 Olympus fluorescence microscope (Exfo America; Olympus, Richardson, TX). Selected images were captured using a CCD camera (Sensys; Photometrics, Tucson, AZ) and Cytovision (Applied Imaging).
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Fig. 3. FISH image showing loss of one copy of the TP53 gene. The metaphase appears stained in blue [40 ,6-diamidino-2-phenylindole (DAPI counterstain)] with only one red signal for the p53 probe.
4. Results 4.1. Chromosome analysis Conventional chromosome analysis of the two patients’ bone marrow cells showed complex karyotypes, which
included a dic(17;20). The karyotype of patient 1 was: 43~45,XY,-6,-11,add(12)(q13),dic(17;20)(p11.2;q11.2),-18, þmar1x2[cp10]/46,XY[10]. The karyotype of patient 2 was: 45,XX,del(5)(q13q33),dic(17;20)(p11.2;q11.2)[cp3]/ 46,XX[17] (Figs. 1 and 2).
Fig. 4. FISH image of a metaphase showing a normal copy of chromosomes 17 and 20 as well as the dic(17;20). The metaphase appears stained in blue (DAPI counterstain). Red signal, chromosome 20 centromere; green signal: chromosome 9 centromere. The dic(17;10) shows both centromeres.
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C.A. Tirado et al. / Cancer Genetics and Cytogenetics 170 (2006) 61e64
4.2. FISH analysis FISH studies showed evidence of a dic(17;20), since both centromeres were located on the same derivative chromosome. The abnormality was evident in both interphase and metaphase cells (Fig. 3). FISH with the p53 probe revealed the loss of TP53 (Fig. 4). FISH using the MLL probe also revealed three MLL signals, one on the normal chromosome 11 and the other two on each of the two marker chromosomes.
5. Discussion Deletions of 17p and 20q are recurrent in hematologic disorders including MDS, myeloproliferative disorders, and AML. Deletion of 17p has been associated with loss of granulocyte maturation, which correlates with progression of the disease, poor response to chemotherapy, and adverse clinical outcome [4e8]. Rearrangements of chromosome 17 are frequent and include balanced and unbalanced rearrangements. Among the unbalanced rearrangements, simple deletions of 17p and the presence of i(17)(q10) have been reported more frequently [7,8]. However, the dic(17;20) described here is an uncommon finding and only few reports can be found in the literature [1,3]. One abnormality that has been observed in association with dic(17;20) is del(5q), which supports an MDS origin of the malignancy in patient 2 [3].
The key event in the dic(17;20) might be the deletion of the tumor suppressor gene TP53 as well as other tumor suppressor genes in 20q that may have a critical role in tumor genesis [3].
References [1] Patsouris C, Michael P, Campbell L. A new nonrandom unbalanced t(17;20) in myeloid malignancies. Cancer Genet Cytogenet 2002; 138:32e7. [2] Watson N, Dunlop L, Robson L, Sharma P, Smith A. 17pe syndrome arising from a novel dicentric translocation in a patient with acute myeloid leukemia. Cancer Genet Cytogenet 2000;118:159e62. [3] ISCN. An international system for human cytogenetics nomenclature. In: Shaffer LG, Tommerup N, editors. Basel: S. Karger, 2005. [4] Fenaux P, Morel P, Lai JL. Cytogenetics of myelodysplastic syndromes. Semin Hematol 1996;33:127e38. [5] Soenen V, Prendhomme C, Roumier C, Daudignon A, Lai JF, Fenaux P. 17p deletion in acute myeloid leukemia and myelodysplastic syndrome. Analysis of breakpoints and deleted segments by fluorescence in situ. Blood 1998;91:1008e15. [6] Pederson B, Kerndrup G. Granulocyte maturation and the chromosome deletion 17p- in primary myelodysplastic syndrome. Acta Haematol 1990;84:77e81. [7] Jonveaux P, Feanux P, Pignon JM, Lai JL, Quiquandon I, Kerchaert JP, Loucheux-Lefebvre MH, Goosens M, Bauters F, Berger R. Mutation in the p53 gene in myelodysplastic syndrome. Oncogene 1991;6:2243. [8] Jary L, Mossafa H, Fourcade C, Genet P, Pulik M, Flandrin G. The 17pe syndrome: a distinct myelodysplastic syndrome entity? Leuk Lymphoma 1982;25:163.