الفهرس 
Acute Myeloid Leukemia
The Chain ReactionOnly 14 pages are availabe for public view
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Abstract
ytogenetic analysis of metaphase and interphase cells is a
key component to the evaluation of all patients with newly
diagnosed or relapsed acute myeloid leukemia (AML). The
malignant cells in most patients with AML have non-random,
acquired clonal chromosomal abnormalities. In some cases,
specific cytogenetic abnormalities are closely, and sometimes
uniquely, associated with morphologically and clinically
distinct subsets of the disease.
Evidence suggests that de novo and secondary AML
occur via similar cytogenetic and genetic pathways, several of
which involve aneuploidy, the loss or gain of chromosomes.
Aneuploidy of specific chromosomes, recurrent translocations
and rearrangements have been detected in different AML
subgroups showing diagnostic, prognostic, and therapeutic
importance.
In the light of this, this work aimed to detect different
numerical chromosomal aberrations in AML patients (trisomy
8, trisomy 13, trisomy 21, monosomy 5 and monosomy 7) in
addition to routine cytogenetic profile using Fluorescence in
situ Hybridization (FISH), and to assess their relation with other
prognostic factors and therapeutic response. To achieve this aim, the present work was carried on 37 AML
patients. They were recruited from the Hematology oncology
Unit, Ain Shams University hospitals and outpatients, during
the period from December 2012 to January 2014. They were 24
(64.9%) males and 13 (35.1%) females, with a male to female
ratio of (1.8:1). Their ages ranged from 19-70 years, with a
mean of (48.4±15.2) years. Diagnosis was based on standard
morphologic, cytochemical and immunophenotyping criteria.
Patients were subdivided into 2 groups: Twenty two newly
diagnosed patients (Group I) and fifteen patients in relapse
(Group II).
Informed consent was obtained from patients to use their
samples in this study. Patients were evaluated at day 28 of
therapy to assess therapeutic response.
All Patients were subjected to the following: Complete
history taking and thorough clinical examination, Laboratory
investigations, including: Complete blood count using LH750
(Beckman coulter), examination of Leishman‘s stained
peripheral blood films, bone marrow aspiration and
examination of Leishman‘s stained bone marrow smears,
cytochemical studies using myeloperoxidase stain.
Immunophenotyping of bone marrow or peripheral blood
samples using EPICS XL coulter flow cytometer to detect the
FAB category. Fluorescence in situ hybridization analysis
(FISH) cytogenetic analysis using the following probes: Centromeric (CEP) 13 for detection of trisomy 13 (+13).
- LSI dual color dual fusion RUNX1-RUNX1T1 {for
detection of t(8;21) (q22;q22), +8 and +21}.
- LSI dual color single fusion PML-RARA for detection of
t(15;17) (q22;q21).
- LSI dual color single fusion BCR-ABL for detection of
t(9;22) (q34;q11).
- LSI CBFB break apart rearrangement for detection of
inv(16) (p13,q22).
- LSI 5q31 with 5p15.2 for detection of deletion 5q and
monosomy 5.
- LSI 7q31 with centromeric control for detection of deletion
7q and monosomy7. Two age-matched healthy volunteers
were used as controls; to check the intensity of signals of the
used probes.
By applying several FISH probes on slides prepared by
culture of PB and/or BM samples, well spread interphases and
metaphases analyses yielded normal cytogenetic profile in 15
(40.5%) patients. Numerical aberrations were detected in 13 out
of the 37 (35.1%) patients, among which +8 was the most
common one, being detected in 5 (13.5%) patients, all were
newly diagnosed patients, loss of chromosomes 5 (-5) was the
second most common followed by -7, the former was detected
in 3 (8.1%) patients while the latter in 2 (5.4%) patients, all of them were in relapse. +21 was observed in 2 (5.4%) patients,
both of them were in relapse, +13 in 1 (2.7%) patient (in
relapse), while structural aberrations were detected in the form
of t(8;21), t(15;17), t(9;22), inv 16, 11q23 rearrangement. All
patients, who were positive for +8, t(8;21); t(15;17) and inv(16)
were newly diagnosed cases.
Follow up of all patients was done at day 28 after induction
therapy by clinical examination, assessment of PB and BM blasts
count, revealed 24/37 (64.9%) patients with complete remission
and 13/37 (35.1%) patients with incomplete remission.
Two (5.4%) out of the 15 (40.5%) patients with normal
cytogenetic profile failed to achieve remission, they may hide
cryptic aberrations or somatic mutations which elucidate the
disturbance of cellular growth, proliferation, and differentiation
processes in hematopoietic progenitor cells. Acquired gene
mutations with prognostic relevance are highly recommended to
be identified as mutations of FLT3, CEBPA, IDH1/2 and NPM1.
Statistical analysis of patients‘ outcome with prognostic
markers among group I (Newly diagnosed patients) revealed
significant association (p<0.05) of CR with TLC < 50 x109/L
(p=0.000) and IPT patterns of M2 and M4 (p=0.042). On the
other hand, age, gender, hepatomegaly, splenomegaly, Hb and
platelet count showed non-significant statistical difference
between the patients who achieved complete remission and
those with incomplete remission (p>0.05). Statistical analysis of patients‘ outcome with prognostic
markers among group II (Patients who were selected in
relapse) revealed significant association (p<0.05) of CR with
TLC < 50 x109/L (p=0.003) and Hb level < 10 g/dl (p=0.038).
On the other hand, age, gender, hepatomegaly, splenomegaly,
platelet, FAB subtype and associated numerical aberrations
showed non-significant statistical difference between the
patients who achieved complete remission and those with
incomplete remission (p>0.05), except for +21, which showed
high significant correlation, FAB subtypes (p=0.002); (being
negative for M2 & M4), and platelet count <100 (p=0.008);
associating its clinical outcome.
In conclusion, the most common numerical
chromosomal aberrations encountered in AML is the
chromosomal gain in the form of trisomy 8, in newly diagnosed
patients with favorable outcome. On the other hand,
chromosomal loss is the most common numerical aberrations in
relapsed patients in the form of -5 as the most common one
related to poor outcome, followed by -7, +21, while +13 is the
least frequent one. Initial TLC, Hb and immunophenotyping
represent the most significant standard prognostic factors in
relation to patients outcome. Moreover, numerical aberrations
in addition to recurrent structural aberrations showed significant
association with patients’ outcome and may be used as
prognostic indicators for therapeutic response.