الفهرس 
Acute Myeloid Leukemia (AML)Only 14 pages are availabe for public view
 |  | from | 208 |  |  |
| | | from | 208 | | |
Abstract
Acute myeloid leukemia is being represented as an
increasingly heterogeneous entity as the molecular aberrations
are defined. Large number of patients reached tocomplete
remission with current chemotherapeutic regimens, so treatment
related relapse risk or death become using as a toolto determin
mainprognosis for patients. Mutations in NPM1A, FLT3, and
DNMT3A genes lead to uncontrolled proliferation of leukemic
cells.
DNA methylation at the cytosine residue of the CpG
dinucleotide is a covalent modification of DNA associated with
gene silencing. Cancer genomes are globally hypomethylated, a
state associated with altered gene expression. Many promoterassociated CpG islands become hypermethylated in cancer, which
is a mechanism of gene silencing. DNA methyltransferases
(DNMTs) catalyze the conversion of cytosine to 5-methyl
cytosine.
Fetal liver tyrosine kinase 3 (FLT3) geneplays important
role in cellular proliferation and differentiation, that encodes a
class III tyrosine kinas. Activation of several downstream signaltransduction mediators are induced by FLT3 ligandi n normal
hematopoietic progenitor cells. Oncogenic mutations in FLT3
result in ligand-indepenent constitutive and deregulated activation of these signaling pathways. Many studies have found
that FLT3-ITD mutation is associated with adverse prognosis.
Nucleophosmin (NPM1), gene is a partner in the
chromosomal translocation of leukemias and lymphomas that
show in the formation of fusion protein. The contribution of
NPM1 to oncogenesis by activating the oncogenic potential of
the fused protein partner.
Aim of the work:
The aim of this study was to detect the fre quency and
prognostic impact of DNMT3A, FLT3-ITD , and NPM1A, gene
mutations in de novo AML patients and to correlate these
mutations with clinical picture, and disease outcome.
Method:
The present study involved 123 newly diagnosed patients
with de novo acute myeloid leukemia (AML), all patients
presented to outpatient clinic of the National Cancer Institute
(NCI), Cairo University, in four years period from March 2010
to April 2014. A peripheral blood count, bone marrow
examination, cytochemical analysis and PCR were carried out
for all cases and subjected to the assessment for the presence of
DNMT3A mutation by Allele Specific Polymerase Chain
Reaction (AS-PCR) then followed by analysis of post-PCR products using Direct Sequencing technique.P olymerase chain
reaction (PCR) used to detect FLT3-ITD mutation, and (ASPCR) analysis then followed by fragment analysis of post-PCR
products using Gene Mapper software to determine NPM1A
mutation.
Results:
DNMT3A, FLT3-ITD, and NPM1A, gene mutations were
detected in 22 (17.9%), 22 (17.9%), and 24 (19.5%), patients
respectively. Combined DNMT3A/FLT3 mutations were
detected in 5 (4.1%), while 84 (68.3%) cases have both wild
genotype, and 34 (27.6%) cases have either mutant genotype. In
NPM1A/FLT3 combination, the both mutant genotypes were
detected in 9 (7.3%) cases, while 86 (69.9%) cases have both
wild genotype, and 28 (22.8%) cases have either mutant
genotype. In DNMT3A/NPM1A combination, the both mutant
genotypes were detected in 3 (2.4%) cases, while, 80 (65%)
cases have both wild genotype, and 40 (32.5%) cases have either
mutant genotype. In DNMT3A/FLT3/NPM1A combinations, the
2 (1.6%) cases have 3 mutant genotypes, and 70 (56.9%) have
triple wild genotype. The presence of NPM1A and DNMT3A
mutations were not significantly associate with age, sex, FAB
subtypes, splenomegaly, hepatomegaly, hemoglobin, total
leucocytic count, platelets and the percent of bone marrow
blasts. The presence of FLT3-ITD mutation was significantly associated with older age (P= 0.029) and non significantly
associated with sex, FAB subtypes, splenomegaly,
hepatomegaly, hemoglobin, total leucocytic count, platelets and
the percent of bone marrow blasts. The presence of NPM1A
mutation was associated with a higher overall survival (OS),
however the difference did not reach the level of significance.
The presence of FLT3-ITD mutation was significantly associated
with a lower OS (P= 0.046), the presence of DNMT3A mutation
was associated with a lower OS, however the difference did not
reach the level of significance. The presence of DNMT3A/FLT3
combination mutation was significantly associated with a lower
OS (P= 0.016). The presence of FLT3-ITD mutation and
DNMT3A mutation were significantly associated with a lower
complete remission (CR) rate (P=0.016 & P=0.016
respectively). NPM1A/FLT3, DNMT3/FLT3, and
NPM1A/DNMT3A combination mutations were significantly
associated with a lower CR rate (P= 0.006, P=0.006 & P=0.023
respectively). For DFS, there was a non significant difference
between the presence or absence of NPM1A, FLT3, or
DNMT3A, gene mutations .