Content uploaded by Yi Xiao
Author content
All content in this area was uploaded by Yi Xiao on Mar 11, 2021
Content may be subject to copyright.
www.springerlink.com Chin J Cancer Res 23(3):239-241, 2011 239
Case Report
Mosaic Trisomy 21 and Trisomy 14 as Acquired Cytogenetic Abnormalities
without GATA1 Mutation in A Pediatric Non-Down Syndrome Acute
Megakaryoblastic Leukemia
Yi Xiao, Jia Wei*, Jin-huan Xu, Jian-feng Zhou, Yi-cheng Zhang**
Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology,
Wuhan 430030, China
DOI: 10.1007/s11670-011-0239-4
Chinese Anti-Cancer Association and Springer-Verlag Berlin Heidelberg 2011
ABSTRACT
One case of acute megakaryoblastic leukemia (AMKL) with trisomy 21, trisomy 14 and unmutated GATA1 gene
in a phenotypically normal girl was reported. The patient experienced transient myelodysplasia before the onset of
AMKL. The bone marrow blasts manifested typical morphology of megakaryoblast both by the May-Giemsa staining
and under the electronic microscopy. Leukemic cells were positive for CD13, CD33, CD117, CD56, CD38, CD41 and
CD61 in flow cytometry analysis. Cytogenetic study showed karyotype of 48, XX, +14, +21 in 40% metaphases.
Known mutations of GATA1 gene in Down syndrome or acquired trisomy 21 were not detected in this case.
Key words: Acute megakaryoblastic leukemia, Myelodysplasia, Cytogenetics, GATA1
INTRODUCTION
Acute megakaryoblastic leukemia (AMKL) is the most
frequent type of acute myeloid leukemia (AML) in children
with Down syndrome (DS)[1]. There are no specific
cytogenetic abnormalities for AMKL. Constitutional or
acquired abnormalities of chromosome 21 are generally
regarded as one of the most frequent abnormalities
occurring in AMKL[2,3]. Acquired trisomy 21 and trisomy 14,
however, is a very rare karyotypic abnormality in
hematological malignancies and has never been reported in
patients with non-DS AMKL. We reported here one case of
pediatric non-DS-AMKL patient who presented with
myelodysplasia as the initial clinical manifestation. The
detailed cytogenetics and the sequence of the GATA1 gene
were analyzed to provide better understanding of
leukemogenesis in this rare case.
CASE REPORT
A one–and-half-year old girl was admitted to our
department with petechia on the lower extremities for three
months. No fever or documented infection was recorded.
No lymph node enlargement and hepatosplenomegaly can
be palpated on physical examination. Complete blood count
indicated thrombocytopenia (blood platelet count: 13×109/L)
and moderate anemia (hemoglobin: 65 g/L) with normal
white blood cell (WBC) counts. Bone marrow aspirate
111111
Received 20101203; Accepted 20110317
*Contributed equally to this study.
**Corresponding author.
E-mail: yczhang@tjh.tjmu.edu.cn
cytology showed intermediately differentiated blasts (14%)
with deep blue cytoplasm and cytoplasmic blebs (Figure 1A).
Marked dysplasias of trilineage blood cells, especially
dysmegakaryocytopoiesis including the presence of micro-
megakaryocytes, were easily found in her bone marrow
smear. On cytochemical staining, these blasts were negative
for myeloperoxide stain, periodic acid-Schiff (PAS) stain,
naphthol-AS-D-Chloroacetate esterase (AS-D-CE) and acid
α-naphthyl acetate esterase (ANAE) stain. Abnormal
localization of immature precursor (AILP) can be observed
in her bone marrow biopsy. The cytogenetic analysis at that
time indicated normal karyotype (46, XX) in 20 metaphases.
She received supportive care and intermittent transfusion of
platelets. To alleviate hemorrhage, she was also prescribed
with immunoglobulin and a moderate dose of corticosteroid
(prednisone, 30 mg/d). After that, her hemoglobin level
gradually recovered while the platelet count fluctuated
between 20×109/L and 50×109/L. On the 90th day after the
first hospitalization, the patient presented a high fever
(39.2º
C at peak) and extreme weakness. Her bone marrow
smear then showed 22.5% megakaryoblasts with round
nuclei of dense chromatin (Figure 1B). Cytoplasm was deep
blue with cloudy-shaped rim. On cytochemical staining,
leukemic blasts were negative for peroxidase (POX), ANAE,
and Sudan black B; PAS was weakly positive. The
ultrastructure of the leukemic blasts was indicative of
megakaryoblasts with irregular morphology and bony
prominence. The nuclei were irregular with obvious nucleoli.
Abundant mitochondria can be observed in its cytoplasm;
rough endoplasmic reticulum was in long and cord shape
(Figure 2). Cytogenetics study demonstrated karyotype of 48,
XX, +14, +21 in 40% (8 of 20) of metaphases (Figure 3). A
240 Chin J Cancer Res 23(3):239-241, 2011 www.springerlink.com
Figure 1. May-Giemsa staining of bone marrow smear. A:
Myelodysplasia with irregular concave, folding or twisting nucleus can
be observed preceding AMKL, (×400). B: Megakaryoblasts with deep
blue cytoplasm and cloudy-shaped rim after transforming from
myelodysplasia into AMKL, (×400).
Figure 2. Ultrastructure of AMKL blast. An AMKL blast from
non-DS AMKL with irregular cytomorphology and bony prominence
can be observed under transmission electronic microscope. The
morphology of nuclei was irregular with obvious nucleoli. Abundant
mitochondria (black arrows) existed in its cytoplasm. Rough
endoplasmic reticulum was in long and cord shape, (×12000).
cluster of abnormal cells which occupied 23% of nucleated
cells at CD45/SSC gating expressed CD33 (58.22%), CD117
(12.29%), CD56 (16.02%), CD38 (39.85%), CD41 (65.5%) and
CD61 (87.5%), but did not express CD2, CD3, CD5, CD10,
CD19 and CD20. RNA was extracted from separated bone
marrow mononuclear cells and screened for mutations in
GATA1 gene by RT-PCR and direct DNA sequencing. PCR
conditions were initial denaturation for 5min at 94º
C,
followed by 30 cycles of 30 s at 94º
C, 30 s at 56º
C and 45 s at
72º
C, using a PCR Thermal Cycler (Applied Biosystem,
USA). PCR amplification products of all coding exons were
prepared using a Qiaquick PCR purification kit (Qiagen,
Germany) to remove unincorporated nucleotides and were
subjected to automated nucleotide sequencing by an ABI
PRISM 3130XL Genetic Analyzer (PerkinElmer/Applied
Biosystems, Foster City, USA). All of the six exons of the
GATA1 gene were directly sequenced. No mutations were
detected in known sites of GATA1 gene that is involved in
the transient myeloproliferative disorder (TMD) and AMKL
of DS (Figure 4). The patient was diagnosed as non-DS
AMKL. Two courses of standard dose cytosine arabinoside
were given to the patient but she failed the induction and
died of severe pneumonia and acute respiratory distress
syndrome 102 days after the diagnosis.
Figure 3. Cytogenetics of AMKL bone marrow. Cytogenetic
analysis showed 48, XX, +14, +21 (40%)/46, XX (60%). The black
arrows indicate trisomy14 and trisomy 21.
Figure 4. Sequencing of GATA1 gene in non-DS AMKL. Direct
sequence of the RT-PCR product from bone marrow cells in this
non-DS AMKL patient. Direct data showed no finding of a deletion of
AG at 128-129 bp.
DISCUSSION
DS is one of the most frequently acquired human
genetic disorders, resulting from the presence of an extra
copy of chromosome 21. Children with constitutional
trisomy 21 have an approximately 500-fold increased risk of
developing AMKL[4]. The cytogenetic profile of AMKL in
children is complex, which reflects the heterogeneity of the
disease. In the analysis of 45 AMKL children, cytogenetic
abnormalities of leukemic cells were classified into seven
categories[5]: normal karyotype or constitutional trisomy 21
in DS-AMKL, other numerical abnormalities only, t(1;22)
(p13;q13), 3q21q26 abnormalities, t(16;21) (p11;q22), -5/del
(5q) and/or -7/del (7q), and other structural changes. To our
best knowledge, mosaic trisomy 21 and trisomy 14 as
acquired cytogenetic abnormalities in non-DS AMKL has
not been reported in literature. In our case, myelodysplasia
(three months) preceded AMKL. Although the exact
mechanism of how trisomy 21 and trisomy 14 contribute to
the leukemogenesis is unknown, it may play a key role in
the transforming from myelodysplasia to AMKL. Only
limited reports with regard to AMKL after myelodysplastic
syndrome (MDS) are available[6,7]. From a retrospective
study of 37 cases of AMKL treated in M.D. Anderson Cancer
www.springerlink.com Chin J Cancer Res 23(3):239-241, 2011 241
Center, 27% patients presented myelodysplasia before
diagnosis with median time of 4 months (2-160 months)[8].
GATA1, an important transcription factor for the
differentiation of the erythroid and megakaryocytic cell
lineages through cooperative regulation of key molecules, is
tightly associated with AMKL in children with DS[9, 10].
Acquired mutations in GATA1, preventing synthesis of full
length GATA1, have been identified in constitutional
trisomy 21 DS-AMKL, suggesting that GATA1 plays a
critical role in trisomy 21 megakaryoblastic leukemo-
genesis[4,11-14]. Mutations in exon 2 of the GATA1 gene
present in almost all cases of DS-associated AMKL[7,14]; in
contrast to DS-AMKL, they were rarely found in patients
with non-DS AMKL[15]. Therefore, all of the exons of the
GATA1 gene were evaluated to confirm that karyotype in
this case was not associated with DS.
In conclusion, a phenotypically normal female case of
non-DS AMKL showing mosaic trisomy 21 and trisomy 14
as acquired cytogenetic abnormalities without GATA1
mutation was reported.
REFERENCES
1. Zipursky A, Peeters M, Poon A. Megakaryoblastic leukemia and
Down's syndrome: a review. Pediatr Hematol Oncol 1987; 4:211-30.
2. Potocki L, Townes PL, Woda BA, et al. Tetrasomy 21 in
megakaryoblastic leukemia. Cancer Genet Cytogenet 1994; 74:66-70.
3. Shin MG, Choi HW, Kim HR, et al. Tetrasomy 21 as a sole acquired
abnormality without GATA1 gene mutation in pediatric acute
megakaryoblastic leukemia: a case report and review of the literature.
Leuk Res 2008; 32:1615-9.
4. Hitzler JK, Cheung J, Li Y, et al. GATA1 mutations in transient leukemia
and acute megakaryoblastic leukemia of Down syndrome. Blood 2003;
101:4301-4.
5. Hama A, Yagasaki H, Takahashi Y, et al. Acute megakaryoblastic
leukaemia (AMKL) in children: a comparison of AMKL with and
without Down syndrome. Br J Haematol 2008; 140:552-61.
6. Polski JM, Galambos C, Gale GB, et al. Acute megakaryoblastic
leukemia after transient myeloproliferative disorder with clonal
karyotype evolution in a phenotypically normal neonate. J Pediatr
Hematol Oncol 2002; 24:50-4.
7. Wechsler J, Greene M, McDevitt MA, et al. Acquired mutations in
GATA1 in the megakaryoblastic leukemia of Down syndrome. Nat
Genet 2002; 32:148-52.
8. Oki Y, Kantarjian HM, Zhou X, et al. Adult acute megakaryocytic
leukemia: an analysis of 37 patients treated at M.D. Anderson Cancer
Center. Blood 2006; 107:880-4.
9. Sandoval C, Pine SR. Down syndrome and GATA1-related transient
leukemia. J Pediatr 2007; 150:e34.
10. Shimizu R, Engel JD, Yamamoto M. Gata1-related leukaemias. Nat Rev
Cancer 2008; 8:279-87.
11. Ahmed M, Sternberg A, Hall G, et al. Natural history of GATA1
mutations in Down syndrome. Blood 2004; 103:2480-9.
12. Cabelof DC, Patel HV, Chen Q, et al. Mutational spectrum at GATA1
provides insights into mutagenesis and leukemogenesis in. Blood 2009;
114:2753-63.
13. Mundschau G, Gurbuxani S, Gamis AS, et al. Mutagenesis of GATA1 is
an initiating event in Down syndrome leukemogenesis. Blood 2003;
101:4298-300.
14. Salek-Ardakani S, Smooha G, de Boer J, et al. ERG is a megakaryocytic
oncogene. Cancer Res 2009; 69:4665-73.
15. Hirose Y, Kudo K, Kiyoi H, et al. Comprehensive analysis of gene
alterations in acute megakaryoblastic leukemia of Down's syndrome.
Leukemia 2003; 17:2250-2.
