Differential prognostic impact of stratified additional chromosome abnormalities on disease progression among Malaysian chronic myeloid leukemia patients undergoing treatment with imatinib mesylate.

The emergence of additional chromosome abnormalities (ACAs) in chronic myeloid leukemia (CML) patients during treatment with a tyrosine kinase inhibitor (TKI) regime is generally associated with resistance to treatment and a sign of disease progression to accelerated phase or blast phase. We report the type, frequency, and differential prognostic impact of stratified ACAs with treatment response in 251 Malaysian CML patients undergoing TKI therapy. ACAs were observed in 40 patients (15.9%) of which 7 patients (17.5%) showed ACAs at time of initial diagnosis whereas 33 patients (82.5%) showed ACAs during the course of IM treatment. In order to assess the prognostic significance, we stratified the CML patients with ACAs into four groups, group 1 (+8/+Ph), group 2 (hypodiploidy), group 3 (structural/complex abnormalities); group 4 (high-risk complex abnormalities), and followed up the disease outcome of patients. Group 1 and group 2 relatively showed good prognosis while patients in group 3 and group 4 had progressed or transformed to AP or blast phase with a median survival rate of 12 months after progression. Novel ACAs consisting of rearrangements involving chromosome 11 and chromosome 12 were found to lead to myeloid BP while ACAs involving the deletion of 7q or monosomy 7 led toward a lymphoid blast phase. There was no evidence of group 2 abnormalities (hypodiploidy) contributing to disease progression. Compared to group 1 abnormalities, CML patients with group 3 and group 4 abnormalities showed a higher risk for disease progression. We conclude that the stratification based on individual ACAs has a differential prognostic impact and might be a potential novel risk predictive system to prognosticate and guide the treatment of CML patients at diagnosis and during treatment.

Hyperdiploid Multiple Myeloma with Novel Complex Structural Chromosome Abnormalities Associated with Poor Prognosis : A Rare Case Report.

Hyperdiploid multiple myeloma (MM) is associated with better prognosis and non-hyperdiploid subtype is associated with variable to adverse prognosis based on the nature of karyotype abnormality.  Rarely exceptions to this hyperdiploid and non-hyperdiploid divisions do exist in a minority. We report an adult male MM patient who showed hyperdiploid karyotype with few novel complex abnormalities and who showed poor clinical outcome. Conventional cytogenetic analysis carried out in 22 GTG banded metaphases showed 53,Y,der(X)t(X;22)(q27;q11.2),+3,+5,+6,+9,+11,+15,der(17)ins(17;1;3)(q11.2;?;?),der(17)ins(17;1;3)(q11.2;?;?),+19,-22,+mar karyotype pattern in 15 metaphases whereas 7 metaphases showed 46,XY karyotype  pattern.  Interphase FISH revealed biallelic del(13q14) and del(17p13) but no translocations involving the 14q32 region. Through Spectral karyotyping FISH, the origin of complex abnormalities involving der(17) chromosome,  translocation t(X;22), and marker chromosome could be clearly delineated. Although the present case showed hyperdiploid karyotype, he showed an adverse prognosis probably due to the co-existence of high risk and complex abnormalities and expired 5 months after initial diagnosis despite standard treatment given.

Aberrant DNA Methylation of SOCS1 Gene is Not Associated with Resistance to Imatinib Mesylate among Chronic Myeloid Leukemia Patients.

BACKGROUND: In exploring the cause of Imatinib Mesylate (IM) resistance among Chronic Myeloid Leukemia (CML) patients who do not harbor BCR-ABL dependent mechanism, BCR-ABL independent pathways are the most probable pathways that should be explored. In BCR-ABL independent pathway, SOCS1 plays an important role as it helps in regulating optimal JAK/STAT activity. OBJECTIVE: To identify the association of SOCS1 gene hypermethylation in mediating IM Resistance. METHOD: The SOCS1 promoter methylation level of 92 BCR-ABL non mutated IM resistant CML patients, 83 IM good response CML patients and 5 normal samples from healthy individuals were measured using Methylation Specific-High Resolution Melt (MS-HRM) analysis. RESULTS: Both primers used to amplify promoter region from -333 to -223 and from -332 to -188 showed less than 10% methylation in all CML and normal samples. Consequently, there was no significant difference in SOCS1 promoter methylation level between IM resistant and IM good response patients. CONCLUSION: SOCS1 promoter methylation level is not suitable to be used as one of the biomarkers for predicting the possibility of acquiring resistance among CML patients treated with IM.

Pharmacogenetics and the treatment of chronic myeloid leukemia: how relevant clinically? An update.

Despite the excellent efficacy and improved clinical responses obtained with imatinib mesylate (IM), development of resistance in a significant proportion of chronic myeloid leukemia (CML) patients on IM therapy have emerged as a challenging problem in clinical practice. Resistance to imatinib can be due to heterogeneous array of factors involving BCR/ABL-dependent and BCR/ABL-independent pathways. Although BCR/ABL mutation is the major contributory factor for IM resistance, reduced bio-availability of IM in leukemic cells is also an important pharmacokinetic factor that contributes to development of resistance to IM in CML patients. The contribution of polymorphisms of the pharmacogenes in relation to IM disposition and treatment outcomes have been studied by various research groups in numerous population cohorts. However, the conclusions arising from these studies have been highly inconsistent. This review encompasses an updated insight into the impact of pharmacogenetic variability on treatment response of IM in CML patients.

Aberrant DNA methylation at HOXA4 and HOXA5 genes are associated with resistance to imatinib mesylate among chronic myeloid leukemia patients.

BACKGROUND: Imatinib mesylate is a molecularly targeted tyrosine kinase inhibitor drug. It is effectively used in the treatment of chronic myeloid leukemia (CML) patients. However, development of resistance to imatinib mesylate as a result of BCR-ABL dependent and BCR-ABL independent mechanisms has emerged as a daunting problem in the management of CML patients. Between these mechanisms, BCR-ABL independent mechanisms are still not robustly understood. AIM: To investigate the correlation of HOXA4 and HOXA5 promoter DNA hypermethylation with imatinib resistance among CML patients. METHODS AND RESULTS: Samples from 175 Philadelphia positive CML patients (83 good response and 92 BCR-ABL non-mutated imatinib resistant patients) were subjected to Methylation Specific High Resolution Melt Analysis for methylation levels quantification of the HOXA4 and HOXA5 promoter regions. Receiver operating characteristic curve analysis was done to elucidate the optimal methylation cut-off point followed by multiple logistic regression analysis. Log-Rank analysis was done to measure the overall survival difference between CML groups. The optimal methylation cut-off point was found to be at 62.5% for both HOXA4 and HOXA5. Chronic myeloid leukemia patients with ≥63% HOXA4 and HOXA5 methylation level were shown to have 3.78 and 3.95 times the odds, respectively, to acquire resistance to imatinib. However, overall survival of CML patients that have ≤62% and ≥ 63% methylation levels of HOXA4 and HOXA5 genes were found to be not significant (P-value = 0.126 for HOXA4; P-value = 0.217 for HOXA5). CONCLUSION: Hypermethylation of the HOXA4 and HOXA5 promoter is correlated with imatinib resistance and with further investigation, it could be a potential epigenetic biomarker in supplement to the BCR-ABL gene mutation in predicting imatinib treatment response among CML patients but could not be considered as a prognostic marker.

BCR-ABL kinase domain mutations, including 2 novel mutations in imatinib resistant Malaysian chronic myeloid leukemia patients-Frequency and clinical outcome.

Discovery of imatinib mesylate (IM) as the targeted BCR-ABL protein tyrosine kinase inhibitor (TKI) has resulted in its use as the frontline therapy for chronic myeloid leukemia (CML) across the world. Although high response rates are observed in CML patients who receive IM treatment, a significant number of patients develop resistance to IM. Resistance to IM in patients has been associated with a heterogeneous array of mechanisms of which point mutations within the ABL tyrosine kinase domain (TKD) are the frequently documented. The types and frequencies of mutations reported in different population studies have shown wide variability. We screened 125 Malaysian CML patients on IM therapy who showed either TKI refractory or resistance to IM to investigate the frequency and pattern of BCR-ABL kinase domain mutations among Malaysian CML patients undergoing IM therapy and to determine the clinical significance. Mutational screening using denaturing high performance liquid chromatography (dHPLC) followed by DNA sequencing was performed on 125 IM resistant Malaysian CML patients. Mutations were detected in 28 patients (22.4%). Fifteen different types of mutations (T315I, E255K, G250E, M351T, F359C, G251E, Y253H, V289F, E355G, N368S, L387M, H369R, A397P, E355A, D276G), including 2 novel mutations were identified, with T315I as the predominant type of mutation. The data generated from clinical and molecular parameters studied were correlated with the survival of CML patients. Patients with Y253H, M351T and E355G TKD mutations showed poorer prognosis compared to those without mutation. Interestingly, when the prognostic impact of the observed mutations was compared inter-individually, E355G and Y253H mutations were associated with more adverse prognosis and shorter survival (P=0.025 and 0.005 respectively) than T315I mutation. Results suggest that apart from those mutations occurring in the three crucial regions (catalytic domain, P-loop and activation-loop), other rare mutations also may have high impact in the development of resistance and adverse prognosis. Presence of mutations in different regions of BCR-ABL TKD leads to different levels of resistance and early detection of emerging mutant clones may help in decision making for alternative treatment. Serial monitoring of BCR-ABL1 transcripts in CML patients allows appropriate selection of CML patients for BCR-ABL1 KD mutation analysis associated with acquired TKI resistance. Identification of these KD mutations is essential in order to direct alternative treatments in such CML patients.

Survival and prognostic factors in Malaysian acute myeloid leukemia patients after allogeneic haematopoietic stem cell transplantation.

Studies of survival outcomes in acute myeloid leukemia (AML) patients treated with allogeneic haematopoietic stem cell transplantation (HSCT) are essential for planning patient care. The objectives of the present study were to determine overall survival (OS) and disease-free survival (DFS) in AML patients treated with allogeneic HSCT, and to identify prognostic factors associated with poor outcome. This study was conducted retrospectively, using data from the Blood and Bone Marrow Transplant, National Transplant Registry, Malaysia. All cases of AML treated with allogeneic HSCT registered at the registry between 1st January 1987 and 31st December 2010 were included in the study. A total of 300 patients were included for final analysis. The Kaplan-Meier method and Cox proportional hazard regression were used for statistical analysis. The overall 10-year OS and DFS for Malaysian AML patients after allogeneic HSCT were 63 and 67 %, respectively. Donor gender, marrow status, and conditioning intensity were identified as important prognostic factors for overall survival, whereas the significant prognostic factors for disease-free survival were ethnic group, donor gender, marrow status, and conditioning intensity. In conclusion, the survival outcomes for Malaysian AML patients treated with allogeneic HSCT were good, and this treatment should be considered the standard therapeutic approach for suitable candidates.