الفهرس 
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Abstract
Chronic myeloid leukaemia (CML) is a myeloproliferative neoplasm characterized
by rearrangement of the long arms of chromosome 9 and 22, resulting in the Philadelphia
(Ph) chromosome, creating the fusion oncogene BCR-ABL1. This genetic event that
encodes for a constitutively active tyrosine kinase occurs in a haemopoietic progenitor and
confers proliferative and anti apoptotic effects.
Major causes of imatinib resistance include the emergence of leukemic clones with
mutations in the kinase domain of BCR-ABL and clonal evolution. chronic phase CML
patients may develop BCR-ABL point mutations after starting the treatment, while others,
almost exclusively patients in more advanced phases of the disease, may present mutation
already at diagnosis.
The aim of the present work was to study the occurrence of T315I BCR- ABL
mutation in chronic myeloid leukemia patients resistant to imatinib therapy.
The study included 35 chronic myeloid leukemia patients resistant to imatinib
therapy. The patients referred to the Hematology Department -Medical Research Institute
and Hematology Department-Alexandria faculty of medicine from November 2013 till
December 2015. Imatinib resistance was defined according to the ELN 2013
recommendations for the management of chronic myeloid leukemia and Patients were
categorized as primary or secondary imatinib resistant .
All participants were asked to freely volunteer to the study and informed written
consent was gathered prior to their inclusion in the study protocol, according to the ethical
guidelines of the Medical Research Institute Alexandria University (Appendix1, Informed
Written Consent for patient participation in a Clinical Research 2011).
All patients were subjected to the following:
1. Detailed history taking.
2. Thorough clinical examination.
3. Routine laboratory investigations including:
- Complete Blood Picture.(13)
- Bone marrow examination.(13)
- Liver function tests.(14)
- Renal function tests.(14).
4. Specific laboratory investigation at imatinib failure.
- Single-tube allele specific polymerase chain reaction:
It is used to detect T315I mutations of ABL gene using the cDNA templates
synthesized from RNA with known percentage of the mutant allele and three
primer pairs. The products will be assessed on a 2% agarose gel.(11)
- Interface FISH (bone marrow samples) for Philadelphia chromosome.
Summary
71
- Real time quantitative PCR (RQ-PCR) for quantitation of BCR-ABL
transcripts using bone marrow or peripheral blood samples.
In the present study, an allele-specific oligonucleotide reverse transcriptase
polymerase chain reaction assay was used to detect T315I mutation in a cohort of 35
imatinib resistant CML patients, with their ages ranged from 22-65 years with a mean of
46.5±13.1, 16 were males and 19 were females, we found that T315I mutation was found
in (9/35) 25.7% of imatinib resistant patients at imatinib failure.
In our study regarding the occurrence of T315I mutations at different phases of CML
disease. 4 patients (44.4%) in groupI were in (advanced stage) blastic crisis or accelerated
phase, while 6 patients in group II (23.1%) were in advanced stage with no statistical
significant difference between both groups. While 5 patients (55.6%) in group I were in
chronic phase, while 20 patients (76.9%) of group II were in chronic phase with no
statistical significant difference between both groups.
Regarding of distribution of CML patients resistant to imatinib with T315I BCRABL
mutation ( group I) CML patients resistant to imatinib who had T315I BCR-ABL
mutation were uniformly distributed within gp I regarding disease phase with no
significant difference between both phases of the disease. While CML patients resistant to
imatinib who had no T315I BCR-ABL mutation had a significant distribution difference
according to the disease phase being significantly higher at chronic phase of the disease
than advanced phase.
The main clinical presentation of CML patients at its three phases were
splenomegaly (94.3%) followed by fatigue (91.4%), bone pain (57.1%), fever
(51.4%),night sweats (45.7%) and hepatomegaly (31.4%).we found no statistically
significant difference between CML patients who had mutation or not regarding the
clinical presentation of the disease.
In the present study, there was a significant distribution difference in patients who
had mutation regarding sokal risk score, high risk constitute 88.9% of patients,
intermediate risk constitute 11.1% while no patients was at low risk, on the other hand, our
study also showed that the majority of those who had T315I mutation (88.9%) and those
who hadn’t (65.4%) were at high risk sokal score with no significant difference between
both groups.
Regarding EUTOS score used to study risks in our patients at diagnosis, we found
that 77.8% of those with mutations and 84.6% of those without mutation were in the high
risk EUTOS score with no statistical significant differences between both groups.
In our study, 16 patients of those without mutation were secondary imatinib
resistance (16 patients out of 26 patient) 61.5% while 5 patients of those with mutation
were primary imatinib resistance (5 patients of 9 patients) 55.6% with no significant
statistical difference between both groups.
In the present study, the median duration in months was shorter (from start of
imatinib treatment till imatinib failure) in patients with T315I mutations (median 36
months) compared to patients without T315I mutation (median of 40.5 months) with no
significant statistical difference between both groups.
Summary
72
In the present study we found that the mean level of qPCR for BCR-ABL in patients
who had T315I mutation was 51.1% ranging (5-100%), while for patients who had not
mutation was 46.3% (ranging 1.5-333%) with no statistical significant difference.
At time of analysis, complete hematological response was achieved in 55.6% of
patients of group I compared to 69.2% of patients of group II with no statistical significant
difference between both groups.
The partial cytogenetic response in T315I positive patients in our study was achieved
in 11.1% of CML patients with mutation and a higher achievement in patients with no
mutation (46.2%) with no statistical difference between both groups.