Overexpression of cancerous inhibitor ofPP2A (CIP2A) in acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy. Protein phosphatase 2A Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase and tumor suppressor that negatively regulates numerous signal transduction pathways. Cancerous inhibitor of PP2A (CIP2A) is an endogenous inhibitor of PP2A. CIP2A overexpression was shown to be a recurrent event in cytogenetic normal AML patients. The aim of the study is to evaluate the prognostic significance of CIP2A overexpression in patients with AML. RESEARCH DESIGN AND METHODS: The study included 174 newly diagnosed cytogenetic normal AML patients. Detection of CIP2A expression was performed using quantitative real-time PCR. RESULTS: CIP2A was overexpressed in 125/174 (71.8%) of patients. Correlation of CIP2A overexpression with other prognostic factors showed significant association with CD34 expression (p = 0.04). CIP2A overexpression was significantly associated with a lower rate of (complete remission) CR (p = 0.019) and shorter disease free survival (DFS) and overall survival (OS) (p < 0.001 and <0.001, respectively). In multivariate analysis, CIP2A overexpression was an independent adverse prognostic factor that negatively affected DFS and OS (p < 0.001, HR:2.8,95%CI:1.7-4.7 and p = 0.002, HR:1.8; 95%CI:1.2-2.65, respectively). CONCLUSION: CIP2A overexpression is a useful prognostic marker in AML.

LMP7 polymorphism may modify the presentation and clinical impact of minor histocompatibility antigens in matched related hematopoietic stem cell transplantation.

Differential expression of minor histocompatibility antigens between the recipient and donor determines their disparity and can be modified by immunoproteasomes that regulate their processing and presentation. We examined the impact of HA-1 and HA-8 disparity, and immunoproteasome LMP7 polymorphism in 130 pairs. In multivariate analysis, HA-1 disparity showed a statistically significant association with an increased incidence of acute graft-versus-host disease (aGVHD) II-IV (p = 0.043, HR: 3.71, 95%CI = 1.04-13.26), while LMP7-Q/Q showed a trend toward increased incidence of aGVHD compared to LMP7-Q/K and K/K genotypes (p = 0.087, HR: 2.36, 95%CI = 0.88-6.31). All HA-1 and HA-8 disparate patients who developed aGVHD had the LMP7-Q/Q genotype. No significant association could be detected between HA-1, HA-8, or LMP7 and chronic GVHD, relapse-free survival (RFS), overall survival (OS), or transplant-related mortality (TRM). In conclusion, we suggested an association between the HA-1 disparity and the risk of developing aGVHD with a possible modifying effect of LMP7.

Nuclear factor-κB1 and MicroRNA-146a polymorphisms and risk of acute graft versus host disease post allogeneic stem cell transplantation.

Acute graft-versus-host disease (aGVHD) is a severe inflammatory complication of haematopoeitic stem cell transplantation. The nuclear factor- Kappa Beta (NF-κB) signaling pathway regulates T cell activation. The NF-κB controls the expression of microRNA-146a (miR-146a) that in turn regulates NF-κB activation through a negative feedback loop. We aim to analyze the association between NF-κB1 encoding p50 (rs28362491, -94 in.ertion/deletion ATTG) and miR-146a (rs2910164, G > C) polymorphisms and risk of aGVHD. Genotyping was performed for 135 HLA-matched donors using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP).The incidence of aGVHD grades II-IV was 24/135 (17.8 %). NF-κB1 genotype and cytomegalovirus infection were significantly associated with risk of aGVHD II-IV (p = 0.022, HR = 3.17, 95 % CI:1.18-8.51 and p = 0.048, HR = 2.56, 95 % CI:1.01-6.52, respectively). In multivariate analysis, NF-κB1homozygous deletion/deletion genotype was the only independent risk factor associated with aGVHD II-IV (p = 0.013, HR = 3.50, 95 % CI:1.30-9.44). No significant association could be observed between miR-146a polymorphism and aGVHD. Combined NF-κB1 and miR146a genotype analysis warrants investigation in a larger cohort. Our preliminary data do not support the association between miR146a and aGVHD, but suggest an association between NF-κB1 and risk of aGVHD that may pave the way for the development of a novel targeted therapy if proved in a larger cohort.

HLA Haplotypes In 250 Families: The Baylor Laboratory Results And A Perspective On A Core NGS Testing Model For The 17th International HLA And Immunogenetics Workshop.

Since their inception, the International HLA & Immunogenetics Workshops (IHIW) served as a collaborative platform for exchange of specimens, reference materials, experiences and best practices. In this report we present a subset of the results of human leukocyte antigen (HLA) haplotypes in families tested by next generation sequencing (NGS) under the 17th IHIW. We characterized 961 haplotypes in 921 subjects belonging to 250 families from 8 countries (Argentina, Austria, Egypt, Jamaica, Germany, Greece, Kuwait, and Switzerland). These samples were tested in a single core laboratory in a high throughput fashion using 6 different reagents/software platforms. Families tested included patients evaluated clinically as transplant recipients (kidney and hematopoietic cell transplant) and their respective family members. We identified 486 HLA alleles at the following loci HLA-A, -B, -C, -DRB1, -DRB3, -DRB4, -DRB5, -DQA1, -DQB1, -DPA1, -DPB1 (77, 115, 68, 69, 10, 6, 4, 44, 31, 20 and 42 alleles, respectively). We also identified nine novel alleles with polymorphisms in coding regions. This approach of testing samples from multiple laboratories across the world in different stages of technology implementation in a single core laboratory may be useful for future international workshops. Although data presented may not be reflective of allele and haplotype frequencies in the countries to which the families belong, they represent an extensive collection of 3rd and 4th field resolution level 11-locus haplotype associations of 486 alleles identified in families from 8 countries.

HLA Class I in Egyptian patients with Behçet's disease: new association with susceptibility, protection, presentation and severity of manifestations.

INTRODUCTION: Behçet's disease is an autoimmune disease with diverse clinical manifestations with vasculitis being the hallmark of the disease. The aim of this work is to study the genetic association between human leukocyte antigen (HLA) class-I molecules of Egyptians with Behçet's disease and the disease susceptibility and clinical patterns. METHODS: Fifty-seven patients diagnosed with Behçet's disease according to the 1990 International Study Group (ISG) criteria for Behçet's disease coming from Egyptian origin up to the third grandfather were included in the study. Healthy controls were taken from HLA Class-I case control studies in Egyptian population yielding a pool of 221 healthy controls. HLA Class-I typing for patients was done using Reverse Sequence specific oligonucleotide probes (rSSO). RESULTS: Male patients represented 89% of the sample. Mean age of onset was 25.81 (± 6.7) years and mean disease duration was 9.47 (± 7.4) years. Behçet's disease was associated with HLA-A*24 and HLA-B*42 (p = 0.001) and highly associated with HLA-A*68 and B*15 and B*51 (p < 0.001). While HLA A*03 and B*52 were protective for Behçet's (p = 0.002 and 0.007). Interestingly, HLA-B*51 and HLA-A*68 (p = 0.005 and 0.023) were associated with the blinding eye disease. HLA-B*51 was protective from Neurological and vascular involvement (p = 0.005 and 0.032, respectively). CONCLUSION: Behçet's disease is associated with HLA Class-I A*24, A*68 and B*15, B*42 and B*51 in Egyptian patients while A*03 and B*52 were found to be protective. Interestingly, HLA B*51 and A*68 could be considered as poor prognostic factor for eye involvement.

Report from the Killer-cell Immunoglobulin-like Receptors (KIR) component of the 17th International HLA and Immunogenetics Workshop.

The goals of the KIR component of the 17th International HLA and Immunogenetics Workshop (IHIW) were to encourage and educate researchers to begin analyzing KIR at allelic resolution, and to survey the nature and extent of KIR allelic diversity across human populations. To represent worldwide diversity, we analyzed 1269 individuals from ten populations, focusing on the most polymorphic KIR genes, which express receptors having three immunoglobulin (Ig)-like domains (KIR3DL1/S1, KIR3DL2 and KIR3DL3). We identified 13 novel alleles of KIR3DL1/S1, 13 of KIR3DL2 and 18 of KIR3DL3. Previously identified alleles, corresponding to 33 alleles of KIR3DL1/S1, 38 of KIR3DL2, and 43 of KIR3DL3, represented over 90% of the observed allele frequencies for these genes. In total we observed 37 KIR3DL1/S1 allotypes, 40 for KIR3DL2 and 44 for KIR3DL3. As KIR allotype diversity can affect NK cell function, this demonstrates potential for high functional diversity worldwide. Allelic variation further diversifies KIR haplotypes. We determined KIR3DL3 ∼ KIR3DL1/S1 ∼ KIR3DL2 haplotypes from five of the studied populations, and observed multiple population-specific haplotypes in each. This included 234 distinct haplotypes in European Americans, 191 in Ugandans, 35 in Papuans, 95 in Egyptians and 86 in Spanish populations. For another 35 populations, encompassing 642,105 individuals we focused on KIR3DL2 and identified another 375 novel alleles, with approximately half of them observed in more than one individual. The KIR allelic level data gathered from this project represents the most comprehensive summary of global KIR allelic diversity to date, and continued analysis will improve understanding of KIR allelic polymorphism in global populations. Further, the wealth of new data gathered in the course of this workshop component highlights the value of collaborative, community-based efforts in immunogenetics research, exemplified by the IHIW.

The effect of killer cell immunoglobulin-like receptor genotype on outcome of hematopoietic stem cell transplantation from matched sibling.

The alloreactivity of natural killer (NK) cell after allogeneic hematopoietic stem cell transplantation (AHSCT) is regulated by the interaction between donor killer immunoglobulin-like receptors (KIRs) and recipient human leukocyte antigen (HLA)-class I molecules. The aim was to identify KIR genes, haplotypes and their HLA-class I ligands and to investigate their association with transplantation outcome. The study included 65 patient/donor pairs who received AHSCT from HLA-matched identical siblings. KIR genotyping was done for donors using reverse sequence specific oligonucleotide probes (rSSO) coupled with luminex technology, while HLA-C genotyping was performed in patients using rSSO strip assay. In multivariate analysis, KIR2DS4 was associated with significant reduced incidence of relapse (p = .002). A trend towards reduced incidence of relapse was also observed with more than two KIR B motifs (p = .09), whereas a significant increased relapse was associated with homozygous HLA-C2 ligand compared to combined C1/C2 and C1/C1 (p = .04). Activating KIR2DS3 was associated with rapid leukocyte engraftment (p = .02). While, KIR 2DL5 was associated with decreased CMV infection (p = .03) and better platelets engraftment (p = .05). KIR genes, haplotypes and HLA-C alleles have an impact on HSCT outcome. Better selection of donors with favorable KIR genotype can improve HLA-matched sibling HSCT outcome especially for AML patients.

Impact of CYP1A1, GSTP1 and XRCC1 genes polymorphisms on toxicity and response to chemotherapy in childhood acute lymphoblastic leukemia.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. The interindividual genetic variations in drug metabolizing enzymes and DNA repair genes influence the efficacy and toxicity of numerous chemotherapeutic drugs affecting the treatment outcome. AIM OF THE WORK: The aim of the study was to investigate the impact of drug metabolizing CYP1, GSTP1 and DNA repair (XRCC1) genes polymorphisms on the toxicity and response to chemotherapy in childhood ALL. PATIENTS AND METHODOLOGY: Ninety seven ALL pediatric patients were genotyped for CYP1A1, GSTP1 ILe105Val and XRCC1 Arg194Tryp single nucleotide polymorphisms (SNPs) using PCR-RFLP. RESULTS: No statistically significant differences were observed between the wild and variant (homozygous and heterozygous) genotypes of the polymorphisms studied in CYP1A1, GSTP1 or XRCC1 genes regarding age, total leukocyte count, immunophenotyping, cytogenetic or risk group. The SNPs in CYP1A1, GSTP1 and XRCC1 genes did not show significant association with complete remission (CR) rate, overall survival (OS) or event free survival (EFS). However, XRCC1 Arg194Trp SNP was associated with higher drug toxicity; carriers of variant genotypes (CT and TT) had a significantly higher frequency of myelosuppression compared to those with the wild CC genotype (21/43[48.8%]) compared to (14/54[25.9%]) (p=0.020). The analysis of the combined effect of studied SNPs did not show any significant association with patient outcome. CONCLUSION: Our study reported a significant association between the DNA repair gene polymorphism and myelosuppression in childhood ALL patients. Adjustment of the dose of chemotherapeutic agents according to XRCC1 Arg194Trp polymorphism may improve outcome in cases with risk of toxicity.

HLA-E polymorphism and clinical outcome after allogeneic hematopoietic stem cell transplantation in Egyptian patients.

UNLABELLED: Human leukocyte antigen-E (HLA)-E in a non-classical major histocompatibility complex (MHC) class I (Ib) molecule. HLA-E-peptide complex acts as a ligand for natural killer (NK) cells and CD8+ T lymphocytes playing a dual role in natural and acquired immune responses. The difference in expression levels between HLA-E alleles was suggested to have impact on transplantation outcome. The aim of the study is to evaluate the clinical effect of HLA-E alleles on transplantation in a group of Egyptian patients. HLA-E genotyping was analyzed in eighty-eight recipients of stem cell transplantation using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). HLA-E*01:03 allele showed a trend towards lower cumulative incidence of relapse at 2 years compared to homozygous HLA-E*01:01 genotype (8% versus 21.5%, p=0.09, HR: 0.30, 95% CI: 0.91-1.69). HLA-E was the only factor showing near significant association with relapse incidence. HLA-E polymorphism did not affect the cumulative incidence of acute GVHD grades II-IV at 100 days, the 2-year cumulative incidence of extensive chronic GVHD, transplant related mortality (TRM) or overall survival (OS). CONCLUSION: the suggested association of HLA-E polymorphism with reduced risk of relapse needs verification in a larger cohort. However, its proposed role in GVL helps better understanding of alloreactivity of T cells and NK cells and their implication in immunotherapy post allogeneic hematopoietic stem cell transplantation.

Comparing prothrombin induced by vitamin K absence-II (PIVKA-II) with the oncofetal proteins glypican-3, Alpha feto protein and carcinoembryonic antigen in diagnosing hepatocellular carcinoma among Egyptian patients.

BACKGROUND: Hepatocellular carcinoma (HCC) is usually asymptomatic in the early stage and does not show elevated alpha-feto protein (AFP). AFP shows 60-80% sensitivity in diagnosing HCC. Glypican3 (GPC-3) is an oncofetal protein that is only detected in HCC cells but not in benign liver tissues, while Carcinoembryonic antigen (CEA) is expressed in various neoplasms including HCC. Although, it is not specific for HCC. Prothrombin induced by vitamin K absence-II (PIVKA-II) is an abnormal prothrombin protein that is increased in the serum of HCC patients. It has higher sensitivity and specificity compared to AFP. The aim of this study is to compare the clinical utility of PIVKA-II with GPC-3, AFP and CEA in diagnosing HCC. PATIENTS AND METHODS: This study included 40 patients with HCC, 10 patients with cirrhosis as a benign control group, and 10 apparently healthy volunteers as normal controls. Serum samples were subjected to routine laboratory investigations, measurement of CEA, AFP using MEIA technique (Axsym), glypican3, and PIVKA-II using ELISA technique in the sera of all patients and controls. RESULTS: All markers showed the highest results in the HCC group. Higher concentrations of PIVKA-II were detected in patients with splenomegaly, and in tumors with size (>3cm). Combination of Glypican-3 and PIVKA-II showed the highest sensitivity, while GPC-3 alone and combination of GPC-3 and AFP showed the highest specificity to differentiate HCC from liver cirrhosis and normal controls. GPC-3, PIVKAII, and combination of both showed the highest sensitivity, while GPC-3 alone showed the highest specificity to differentiate HCC from liver cirrhosis. CONCLUSION: Glypican-3 is the only oncofetal antigen that showed comparable high diagnostic accuracy as PIVKA-II in diagnosing HCC among Egyptian patients.

CTLA-4 polymorphism and clinical outcome post allogeneic hematopoietic stem cell transplantation.

CTLA-4 inhibitory molecule plays an important role in regulating T cell activation. It is considered a crucial element in keeping the immune balance and has been implicated in cancer, autoimmunity and transplantation immunology. Inconsistent observations are reported regarding its association with hematopoietic stem cell transplantation (HSCT). Genotyping of CTLA-4 was performed in recipients and their HLA-matched donors for +49A/G and CT60 polymorphisms (80 and 94 pairs, respectively) using PCR-RFLP. No association was encountered between both polymorphisms in patients and donors and acute or chronic graft versus host disease. Significant association was observed between recipient +49A/G G allele and lower disease-free survival and overall survival compared to AA genotype (HR: 2.17, p = 0.03, 95% CI: 1.05-4.48 and HR: 2.54, p = 0.01, 95% CI: 1.16-5.54), respectively. Our results suggest that CTLA-4 genotyping may predict outcome in patients post HSCT. To validate our results, further studies on a larger cohort are needed.

Prognostic significance of WT1 expression at diagnosis and end of induction in Egyptian adult acute myeloid leukemia patients.

BACKGROUND: Wilms' tumor (WT1) gene overexpression has been reported in the majority of acute myeloid leukemia (AML) patients at diagnosis and has been evaluated as prognostic and minimal residual disease (MRD) marker. PATIENTS AND METHODS: WT1 overexpression was evaluated in 68 adult AML patients at diagnosis and at the end of induction using quantitative real-time polymerase chain reaction (PCR). RESULTS: No significant associations were encountered between WT1 overexpression at diagnosis and other prognostic factors. Complete remission (CR) was achieved in 74% of the patients with WT1 overexpression compared to 80% of patients with normal levels (P = 0.5). No significant associations were encountered between WT1 overexpression at diagnosis and disease-free survival (DFS) or overall survival (OS) (P = 0.6 and 0.3, respectively). At the end of induction, the median duration of DFS in patients achieving ≥ 2 log reduction was not reached compared to only 5 months (range: 2.1-7.9 months) in those attaining <2 log reduction (P = 0.2). The median duration of OS in patients achieving ≥ 2 log reduction was 13 months (range: 0-33.3 months) compared to 7.5 months (5.4-9.6 months) in those attaining <2 log reduction (P = 0.2). The survival at 1 year in patients achieving ≥ 2 log was double the group with <2 log reduction (67% compared to 33%). CONCLUSION: Our results, although not reaching the level of significance, probably due to the small sample size, still suggest that the early assessment of WT1 transcript level at the end of induction in patients in CR may have a prognostic significance on clinical outcome and may thus be a useful marker for risk stratification especially in patients lacking disease-specific marker.

Can Glypican3 be diagnostic for early hepatocellular carcinoma among Egyptian patients?

BACKGROUND: Because of the high prevalence of hepatocellular carcinoma (HCC) in Egypt, new markers with better diagnostic performance than alpha-feto protein (AFP) are needed to help in early diagnosis. The aim of this work was to compare the clinical utility of both serum and mRNA glypican3 (GPC3) as probable diagnostic markers for HCC among Egyptian patients. MATERIALS AND METHODS: A total of 60 subjects, including 40 with HCC, 10 with cirrhosis and 10 normal controls were analyzed for serum GPC3 (sGPC3) by ELISA. GPC-3 mRNA from circulating peripheral blood mononuclear cells was amplified by RT-PCR. Both markers were compared to some prognostic factors of HCC, and sensitivity of both techniques was compared. RESULTS: Serum glypican-3 and AFP were significantly higher in the HCC group compared to cirrhotic and normal controls (p<0.001). Sensitivity and specificity were (95% each) for sGlypican-3, (82.5% and 85%) for AFP, and (100% and 90%) for Glypican3 mRNA , and (80% and 95%) for double combination between sGPC3 and AFP respectively. CONCLUSION: Both serum GPC-3 and GPC-3mRNA are promising diagnostic markers for early detection of HCC in Egyptian patients. RT- PCR proved to be more sensitive (100%) than ELISA (95%) in detecting glypican3.

The Clinical Implications of Methylated p15 and p73 Genes in Adult Acute Lymphoblastic Leukemia.

BACKGROUND: Aberrant methylation of promoterassociated CpG islands is an epigenetic modification of DNA which is associated with gene silencing. It plays an important role in the leukemia pathogenesis. This phenomenon is frequently observed in acute lymphoblastic leukemia (ALL) and results in the functional inactivation of its associated genes. The aim of this study is to investigate the frequency and the prognostic impact of p15 and p73 genes methylation in adult acute lymphoblastic leukemia patients. PATIENTS AND METHODS: Methylation-specific polymerase chain reaction (PCR) was used to analyze methylation of the p15 and p73 genes in 51 newly diagnosed adult ALL patients. RESULTS: The methylation frequencies of p15 and p73 genes at diagnosis were 41.2% and 27.5% respectively, while concomitant methylation was detected in 14% of the patients. Concomitant methylation of p15 and p73 genes was associated with significant lower rate of CR compared to patients without methylation (57% versus 90%), p=0.008. Overall survival (OS) was not affected by p15 methylation, but was poorer with p73 methylation and the difference was near significant (p=0.059). For patients without meyhylation, the survival benefit was significant when compared to patients with p15, p73 or both genes methylation (p=0.047). The leukemia free survival was not affected by the methylation status of single gene p15 or p73, but tended to be worse in patients with methylated p15, p73 or both genes when compared to patients without methylation (p=0.08). CONCLUSION: Aberrant p73 promoter methylation is a potential prognostic factor in adult ALL patients. P15 methylation is frequent in Egyptian adult ALL patients, its concomitant methylation with p73 is of poor prognostic significance. Identification of these molecular targets improve risk assessment and selection of appropriate therapy. KEY WORDS: Methyaltion - p15 - p73 - Adult acute lymphoblastic leukemia.

Prognostic utility of routine chimerism testing at 2 to 6 months after allogeneic hematopoietic cell transplantation.

The utility of routine chimerism analysis as a prognostic indicator of subsequent outcomes after allogeneic hematopoietic cell transplantation (HCT) with myeloablative conditioning regimens remains controversial. To address this controversy, routine chimerism test results at 2 to 6 months after HCT with myeloablative conditioning regimens were evaluated for association with subsequent risk of chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse, and overall mortality. Only 70 of 1304 patients (5%) had < 95% donor-derived cells in the marrow. Low donor chimerism in the marrow occurred more often in patients with low-risk diseases compared with those with higher-risk diseases and was significantly associated with a reduced risk of chronic GVHD. Among 673 patients evaluated, 164 (24%) had < 85% donor-derived T cells in the blood. Low donor T cell chimerism was more frequent in patients with low-risk diseases compared with those with higher-risk diseases, in those who received conditioning with busulfan compared with those who received conditioning with total body irradiation, and in those with lower-grade acute GVHD. Low donor T cell chimerism in the blood was significantly associated with a reduced risk of chronic GVHD but not with a reduced risk of relapse, NRM, or overall mortality. Routine testing of chimerism in the marrow and blood at 2 to 6 months after HCT with myeloablative conditioning regimens may be helpful in documenting engraftment in clinical trials, but provides only limited prognostic information in clinical practice.

p15 (INK4B) and E-cadherin CpG island methylation is frequent in Egyptian acute myeloid leukemia.

BACKGROUND: Hypermethylation within the promoters of selected genes is an epigenetic pathway that appears to be especially common in all types of human haematopoeitic neoplasms. It is usually associated with inactivation of the involved genes, and can be reversed using demethylating agents. The aim of this study is to evaluate the frequency of p15 and E-cadherin promoter methylation in Egyptian acute myeloid leukemia (AML) patients in an attempt to identify a subset of patients who might be candidates for demethylating agents as a form of targeted therapy either as a primary or as an adjunct to current standard induction and post-remission regimens. MATERIAL AND METHODS: In the present work we have studied tumor-associated aberrant p15 and E-cadherin promotor methylation in 59 newly diagnosed acute myeloid leukemia (AML) patients using methylation specific PCR. RESULTS: Aberrant p15 promoter methylation was detected in 49% (29/59) of the patients. In 4 of these patients, no DNA could be amplified by the p15 unmethylated reaction showing a complete methylation of both alleles in the examined region. In the remaining 25 cases both methylated and unmethylated DNA could be amplified. Aberrant methylation of E-cadherin was detected in 63% (37/59) of the cases. In all of these cases both the methylated and the unmethylated alleles were amplified denoting partial methylation of the examined region. Concomitant methylation of p15 and E-cadherin was detected in 40% (23/59) of all the cases tested, while in 27% (16/59) of the cases both genes were not methylated. CONCLUSION: These results demonstrate that p15 and E-cadherin promoter methylation are frequent events in Egyptian AML and provide an impetus for larger studies to define the extent and pattern of methylation in the various subgroups of AML. Methylation studies, therefore, represent a novel additional tool to define the subset of patients who might benefit from demethylating agents,thus providing the molecular basis for targeted therapeutic approaches and better designing of risk-adapted therapy.

Glutathione S-transferase GSTM1 and GSTT1 polymorphisms in adult acute myeloid leukemia; its impact on toxicity and response to chemotherapy.

BACKGROUND AND PURPOSE: Heterogeneity in patient' s response to chemotherapy is consistently observed across populations. Pharmacogenomics, the study of inherited differences in drug disposition and effects, is emerging as a tool to predict efficacy and toxicity of drugs. Glutathione S-transferases (GST) are involved in the metabolism and detoxification of environmental carcinogens and some classes of chemotherapeutics. Polymorphism of GSTM1 and GSTT1, in the form of homozygous deletion, is encountered in varying frequencies in normal population. It has been associated with altered response and toxicity from cytotoxic chemotherapy. In this study, we investigated the impact of these polymorphisms on response and side effects of chemotherapy in adult acute myeloid leukaemia (AML) patients. Correlations between these genetic polymorphisms and other prognostic factors were also investigated. PATIENTS AND METHODS: We genotyped GSTM1 and GSTT1 in 98 adult AML patients using multiplex PCR. Induction therapy included Doxorubicin and Cytosine arabinoside (3+7) regimen. Treatment outcomes were compared in those with or without GSTM1 and GSTT1 genes. RESULTS: The frequencies of GSTM1 null and GSTT1 null genotypes were 56% and 14%, respectively. Six percent (6%) were double null. The rate of toxic death during induction was 3/7 (43%) and 17/56 (30%) in GSTT1 null and GSTT1 present patients, respectively, p=0.67. This constituted 75% and 42% of total deaths in each group, respectively, p=0.31. Differences were not statistically significant. On the other hand, the rate of complete remission (CR) in patients with GSTM1 present compared to those with GSTM1 null genotype was 12/27 (48%) versus 23/36 (64%), p=0.21. GSTT1 null genotype was significantly associated with lymphoid marker (mainly CD7) expression (p=0.03), known with its adverse effect on prognosis. Overall survival and disease-free survival were similar in patients with and without the genes. No significant associations were encountered between GST genotypes and treatment outcomes. CONCLUSION: Our data suggest possible association, though not significant, between GSTT1 null genotype and toxic death during induction and between GSTM1 present genotype and lower rate of CR. Studies on larger numbers are needed focusing on selection of anticancer agents to avoid adverse reactions and therapeutic failure, with special emphasis on drug toxicity and dose adjustment.

Comparison of variable number tandem repeat and short tandem repeat genetic markers for qualitative and quantitative chimerism analysis post allogeneic stem cell transplantation.

BACKGROUND: Analysis of donor chimerism has become a routine procedure for the documentation of engraftment after allogeneic hematopoietic stem cell transplantation. Quantitative analysis of chimerism kinetics has been shown to predict graft failure or relapse. In this study, we compared the use of variable number tandem repeats (VNTR) and short tandem repeats (STR) as polymorphic genetic markers in chimerism analysis. This study included qualitative and quantitative assessment of both techniques to assess informative yield and sensitivity. PATIENTS AND METHODS: We analyzed 206 samples representing 40 transplant recipients and their HLA-identical sibling donors. A panel of six VNTR loci, 15 STR loci and 1 sex chromosome locus was used. Amplified VNTR products were visualized in an ethidium bromide-stained gel. STR loci were amplified using fluorescent primers, and the products were analyzed by capillary electrophoresis. RESULTS: VNTR and STR analysis gave comparable qualitative results in the majority of cases. The incidence of mixed chimerism (MC) by STR analysis was 45% compared to 32% in cases evaluated by VNTR analysis. STR markers were more informative; several informative loci could be identified in all patients. Unique alleles for both patient and donor could be identified in all patients by STR versus 32/40 by VNTR analysis. The STR markers were also more sensitive in the detection of chimerism. The size of VNTR alleles and differences between the size of donor and recipient VNTR alleles affected the sensitivity of detection. With both techniques, quantitative assessment of chimerism showed some discrepancies between the estimated and the calculated percentage of donor DNA. Discordance between the two estimates was observed in 8/19 patients with MC. However, sequential monitoring of the relative band intensity of VNTR alleles offered some insight into the direction of change in engraftment over time. CONCLUSION: The higher yield of informative loci with STR and the automated measurement of amplified STR 103 products offered the advantages of more rapid and accurate quantitative assessment of chimerism. The choice between these two techniques depends on the need for quantitative or qualitative information, the availability of equipment, and the cost.