Vol.2, No.9, 517-520 (2013) Case Reports in Clinical Medicine
A novel cytogenetic abnormality r(7)(::p11.2->q36.3::)
in a Philadelphia-positive chronic myeloid leukemia
W alid Al Achkar1*, Abdulsamad Wafa1, Abdulmunim Aljap awe2,
Moneeb Abdullah Kassem Othman3, Thomas Liehr3
1Human Genetics Division, Molecular Biology and Biotechnology Department, Atomic Energy Commission, Damascus, Syria;
*Corresponding Author: ascientific@aec.org.sy
2Mammalians Biology Division, Molecular Biology and Biotechnology Department, Atomic Energy Commission, Damascus, Syria
3Jena University Hospital, Institute of Human Genetics, Jena, Germany
Received 24 September 2013; revised 17 October 2013; accepted 18 November 2013
Copyright © 2013 Walid Al Achkar et al. This is an open access article distributed under the Creative Commons Attribution License,
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The so-called Philadelphia (Ph) chromosome is
present in more than 90% of chronic myeloid
leukemia (CML) cases. It results in juxtaposition
of the 5' part of the BCR gene on chromosome
22 and the 3' part of the ABL1 gene on chromo-
some 9. An additional acquired monosomy 7 or
deletion of 7q is associated with poor prognosis
in a variety of myeloid disorders. Here we report
a novel Ph chromosome positive CML case with
a ring chromosome 7 [r(7)]. Immunophenotyping
was comp ati ble with CML, although 4.5% of total
leucocytes appeared like acute myelogeneous
leukemia (AML) subtype M2. The r(7) was char-
acterized in detail by array-proven multicolor
banding (aMCB), the latter being of enormous
significance to characterize breakpoint regions
in detail. Underlying mechanisms and prognos-
tic are discussed, as ring chromosomes are rare
cytogenetic abnormalities in hematopoietic ma-
Keywords: Chronic Myeloid Leu kemia (CML); Ring
Chromosome 7; Del(7p); Fluorescen ce in Situ
Hybridization (FISH); Reverse Transcription
Polymerase Chain Reaction (RT-PCR);
Array-Proven Multicolor Banding (aMCB)
The so-called Philadelphia (Ph) chromosome is typical
for by far over 95% of patients suffering form chronic
myeloid leukemia (CML), a clonal malignant disorder of
a pluripotent hematopoietic stem cell. A reciprocal trans-
location t(9;22)(q34;q11) leads to the formation of the
Philadelphia (Ph) chromosome and a derivative of chro-
mosome 9. The 3' portion of the ABL1 oncogene is
translocated from 9q34 to the 5' portion of the BCR gene
on 22q11.2. This leads to the formation of a chimeric
BCR/ABL gene on the derivative chromosome 22 [1]. It
is known since years that the expression of the chimeric
BCR/ABL protein has an increased tyrosine kinase activ-
ity and plays an essential role in the pathogenesis of
CML [2].
Ring chromosomes are rare cytogenetic abnormalities
that occur when the two ends of a chromosome fuse to-
gether and form a ring shape. Breaks in the chromosome
arms and fusion of the proximal broken ends can lead to
ring formation with loss of distal chromosomal material.
Alternatively, rings can be formed by telomere dysfunc-
tion [3].
Complete or partial loss of chromosome 7, predomi-
nantly monosomy 7 or deletion of 7q, is associated with
a variety of myeloid disorders, including de novo pre-
leukemic myelodysplastic syndrome (MDS) and acute
myelogenous leukemia (AML) in children and adults, as
well as therapy-related ones in the latter [4,5]. Also it has
been reported in adult ALL, in which they frequently
occur as secondary aberrations associated with a Ph
chromosome and it is an adverse factor in both child-
hood and adult Ph + ALL [6]. Additionally, deletions of
7p confer an inferior outcome in children with ALL, re-
gardless of the presence of other poor prognostic features,
Copyright © 2013 SciRes. OPEN ACCESS
W . Al Achkar et al. / Case Reports in Clinical Medicine 2 (2013) 517-520
whereas deletions of 7q are not associated with a worse
outcome [6].
Here we reported a novel case of a Ph chromosome
positive CML with r(7) and immunophenotyping consis-
tent with CML, although 4.5% of total leucocytes showed
AML M2 subtype.
2.1. Case Report
A 55-year-old male was diagnosed as suffering from
CML in chronic phase (CP). In June 2010 the white
blood cell count (WBC) was 93 × 109/l with 49.3% neu-
trophils, 19.6% lymphocytes, 14.1% monocytes, 3.4%
eosinophils, and 13.6% basophils. The platelets count
was 181 × 109/l and the hemoglobin level was 10.6 g/dl.
A previous physical examination revealed splenomegaly.
Serum lactate dehydrogenase (LDH) was 2057 U/l (nor-
mal up to 480 U/l), serum alanine aminotransferase (ALT)
was 46 U/l (normal up to 41 U\l) and serum aspartate
aminotransferase (AST) was 42 U/l (normal up to 40 U/l).
Afterwards he was lost during follow-up.
2.2. Chromosome Analysis
Chromosome analysis using GTG-banding was per-
formed according to standard procedures [7] before che-
motherapeutic treatment. A total of 20 metaphase cells
derived from unstimulated bone marrow culture were
analyzed. Karyotypes were described according to the
International System for Human Cytogenetic Nomencla-
ture [8].
2.3. Molecular Cytogenetics
Fluorescence in situ hybridization (FISH) using LSI
BCR/ABL dual color dual fusion translocation probe
(Abbott Molecular/Vysis, USA) was applied according to
manufacturer's instructions [9]. FISH using a chromo-
some-7-specific aMCB probe set based on microdissec-
tion derived region-specific libraries was done as previ-
ously reported [10]. A total of 20 metaphase spreads
were analyzed, each using a fluorescence microscope
(AxioImager.Z1 mot, Zeiss) equipped with appropriate
filter sets to discriminate between a maximum of five
fluorochromes plus the counterstain DAPI (4',6-dia-
mino-2-phenylindole). Image capturing and processing
were carried out using an ISIS imaging system (Meta-
Systems, Altlussheim, Germany).
2.4. Reverse Transcriptase-Polymerase
Chain Reaction (RT-PCR) for BCR/ABL
Fusion Transcripts
RT-PCR was carried out as previously described [11].
2.5. Immunophenotyping
Immunophenotyping of leukemic blasts was per-
formed as previously described [12].
Prior to chemotherapy treatment banding cytogenetics
revealed a karyotype 46, XY, t(9;22) [7]/46, XY, idem,
r(7) [11]/47, XY, idem + 8 [2] (Figure 1(a)). Dual-color-
FISH using a probe specific for BCR and ABL revealed
that a typical Ph chromosome with BCR/ABL-translo-
cation was present (Figure 1(b)). RT-PCR analysis of the
fusion transcript showed a band corresponding to the
b2a2 transcript, most often found in CML (data not
shown). Together with aMCB-result (Figure 1(c)) the
final karyotype was determined as: 46, XY,
t(9;22)(q34;q11)[7]/46, XY, r(7)(::p11.2->q36.3::),
t(9;22)(q34;q11)[11]/47, XY,+8,t(9;22)(q34;q11)[2]/.
The specimen submitted has a high WBC count
>100,000 cells/mm3. Neutrophiles (86% of all leuco-
cytes), showed abnormal intensity staining patterns for
CD16 (49.4%), CD32 (62.7%), CD10 (31%), CD33
(49.4%), CD15 (57.1%), CD13 (43.3%), CD11b (27.2%),
and CD11c (41.5%). These cells expressed CD123
(67.5%). Overall, this result was indicative for chronic
Figure 1. (a) GTG-banding revealed a r(7)(::p11.2->q36.3::)
besides derivative chromosomes 9 and 22. All derivative chro-
mosomes are highlighted by arrow heads; (b) Metaphase FISH
using probes for BCR (green) and ABL (red) confirmed Ph
chromosome presence; (c) The application of aMCB 7 charac-
terized the r(7)(::p11.2->q36.3::) comprehensively. Abbrevia-
tions: # = chromosome; der = derivative chromosome; Ph =
Copyright © 2013 SciRes. OPEN ACCESS
W . Al Achkar et al. / Case Reports in Clinical Medicine 2 (2013) 517-520 519
myeloproliferative disorder, most likely a CML, subse-
quent to an MDS. However, there was as well another
cell population, which represented ~4.5% of all leuco-
cytes, showing an AML-M2 phenotype. These cells have
high forward scatter, low side scatter pattern and were
CD45+ dim (4.5%), CD34+ (4.9%), CD33+ (4.4%),
CD38+(4.8%), CD32+ (4.9%), CD123+ (4.9%). These
cells expressed CD13 (2.6%), CD15 (2.5%), CD11c
(1.9%), HLADr (2.8%), CD117 (2.3%) heterogeneously,
and were CD16, CD64, CD11b, CD10, CD41a,
CD235a, CD3, CD19.
According to the literature, a r(7) involved the short
arm is a rare but recurrent cytogenetic abnormality ob-
servable in AML {r(7)(p15q35) and r(7)(p22q31)} [13],
hepatosplenic T-cell lymphoma [r(7)(p?;q?) [14]] and
acute megakaryoblastic leukemia [15]. To the best of our
knowledge, the present case is the only one ever seen
case of a Ph chromosome-positive CML-CP with de
novo a r(7)(::p11.2->q36.3::); notably there was another
Ph-positive clone with trisomy 8 as secondary abnormal-
ity [14].
The progression of CML from CP to blast crisis (BC)
is frequently associated with nonrandom secondary chro-
mosomal aberrations such as +8, i(17q), +19 and an extra
Ph chromosome [16].
Ring chromosomes are rare cytogenetic abnormalities
that occur in less than 10% of hematopoietic malignan-
cies but have been reported in up to 70% of mesenchy-
mal tumors [3].
Monosomy 7 or deletion of 7q in these disorders is
associated with poor prognosis [17]. It has been hy-
pothesized that there is a tumor suppressor gene (TSG)
on chromosome arm 7q that contributes to the patho-
genesis of these diseases [18]. However, monosomy 7 or
structural abnormalities resulting in the deletion of 7p
were infrequent in childhood ALL to confer increased
risk of treatment failure in Ph-positive cases, and it has
been hypothesized that a TSG on 7p may contribute to
the poor outcome of these patients [6].
Both monosomy 7 and del (7p) are of the additional
chromosomal abnormalities and they associated with
adverse prognostic factors in CML patients treated with
IM as a frontline therapy [19,20].
Recent studies have reported that major route abnor-
malities such as trisomy 8 at diagnosis were related to a
worse outcome t(9,22) [20,21].
In conclusion, we reported here a novel case of a Ph
chromosome positive CML in chronic phase with a new
cytogenetic abnormality r(7) resulting in the deletion of
7p and immunophenotyping was consistent with CML
although 4.5% of total leucocytes showed acute mye-
logeneous leukemia (AML) subtype M2. The r(7) and
del 7p might be a marker for adverse prognosis in CML.
We thank Prof. I. Othman, the Director General of Atomic Energy
Commission of SYRIA (AECS) and Dr. N. Mirali, Head of Molecular
Biology and Biotechnology Department for their support. This work
was supported by the AECS, in parts by the DAAD, Stefan-Morsch-
Stiftung and the Monika-Kutzner-Stiftung.
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