Section of Hematology Oncology

Doha, Qatar

Section of Hematology Oncology

Doha, Qatar

Time filter

Source Type

Bose P.,Section of Hematology Oncology | Bose P.,The University of Oklahoma Health Sciences Center | Parekh H.D.,The University of Oklahoma Health Sciences Center | Holter J.L.,Section of Hematology Oncology | And 2 more authors.
Journal of Clinical Microbiology | Year: 2011

Posaconazole is widely used for prophylaxis against invasive fungal infections in patients undergoing myeloablative therapy. Disseminated fusariosis is a serious invasive mold infection in such patients. Preclinical and clinical studies indicate activity of posaconazole against Fusarium. We describe two cases of disseminated fusariosis that occurred despite posaconazole prophylaxis. Copyright © 2011, American Society for Microbiology.


Zhang X.,Section of Hematology Oncology | Delaney S.M.,Section of Hematology Oncology | Wing C.,Section of Hematology Oncology | Mcquade J.,Section of Hematology Oncology | And 2 more authors.
Genetics | Year: 2013

Elucidating cytosine modification differences between human populations can enhance our understanding of ethnic specificity in complex traits. In this study, cytosine modification levels in 133 HapMap lymphoblastoid cell lines derived from individuals of European or African ancestry were profiled using the Illumina HumanMethylation450 BeadChip. Approximately 13% of the analyzed CpG sites showed differential modification between the two populations at a false discovery rate of 1%. The CpG sites with greater modification levels in European descent were enriched in the proximal regulatory regions, while those greater in African descent were biased toward gene bodies. More than half of the detected population-specific cytosine modifications could be explained primarily by local genetic variation. In addition, a substantial proportion of local modification quantitative trait loci exhibited population-specific effects, suggesting that genetic epistasis and/or genotype × environment interactions could be common. Distinct correlations were observed between gene expression levels and cytosine modifications in proximal regions and gene bodies, suggesting epigenetic regulation of interindividual expression variation. Furthermore, quantitative trait loci associated with population-specific modifications can be colocalized with expression quantitative trait loci and single nucleotide polymorphisms previously identified for complex traits with known racial disparities. Our findings revealed abundant population-specific cytosine modifications and the underlying genetic basis, as well as the relatively independent contribution of genetic and epigenetic variations to population differences in gene expression. © 2013 by the Genetics Society of America.


Pai R.K.,Cleveland Clinic | Van Besien K.,Section of Hematology Oncology | Artz A.S.,Section of Hematology Oncology | O'Donnell P.H.,Section of Hematology Oncology | O'Donnell P.H.,University of Chicago
Leukemia and Lymphoma | Year: 2012

Most cases of veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) occur <21 days after allogeneic hematopoietic stem cell transplant (HCT). Rarely, however, VOD/SOS can occur later, and can be confused with other causes. We report the clinicopathologic features of eight patients with advanced hematologic malignancies developing VOD/SOS >30 days after dose-escalated busulfan/fludarabine/alemtuzumab and HCT. Median time to diagnosis was 52 days (range: 33-77). For seven patients, VOD/SOS was confirmed by liver biopsies showing classical features including reticulin deposition within sinusoids, central vein occlusions, hepatocyte atrophy/necrosis, sinusoidal/perivenular hemorrhage and sparing of portal tracts. VOD/SOS risk was directly related to higher busulfan plasma exposures. Two patients died from VOD/SOS, and in another two patients VOD/SOS was contributory to death. Late-onset VOD/SOS may be underrecognized and should be considered in the differential diagnosis of patients undergoing HCT, particularly after high dose busulfan. Liver biopsy should be entertained even late in the course if appropriate signs/symptoms exist. © 2012 Informa UK, Ltd.


PubMed | Section of Hematology Oncology and University of Chicago
Type: Journal Article | Journal: Blood | Year: 2016

BRCA1 is critical for maintenance of genomic stability and interacts directly with several proteins that regulate hematopoietic stem cell function and are part of the Fanconi anemia (FA) double-strand break DNA repair pathway. The effects of complete BRCA1 deficiency on bone marrow (BM) function are unknown. To test the hypothesis that Brca1 is essential in hematopoiesis, we developed a conditional mouse model with Mx1-Cre-mediated Brca1 deletion. Mice lacking Brca1 in the BM have baseline cytopenias and develop spontaneous bone marrow failure or diverse hematologic malignancies by 6 months of age. Brca1(-/-) BM cells have a reduced capacity to form hematopoietic colonies in vitro and to reconstitute hematopoiesis in irradiated recipients, consistent with a hematopoietic progenitor functional defect. Brca1(-/-) BM cells also show FA-like hypersensitivity to the DNA crosslinking agent mitomycin C, and karyotypes feature genomic instability. Taken together, our results show that loss of Brca1 in murine BM causes hematopoietic defects similar to those seen in people with FA, which provides strong evidence that Brca1 is critical for normal hematopoiesis and that Brca1 is a bona fide FA-like gene.


Wheeler H.E.,Section of Hematology Oncology | Dolan M.E.,Section of Hematology Oncology
Pharmacogenomics | Year: 2012

The ability to predict how an individual patient will respond to a particular treatment is the ambitious goal of personalized medicine. The genetic make up of an individual has been shown to play a role in drug response. For pharmacogenomic studies, human lymphoblastoid cell lines (LCLs) comprise a useful model system for identifying genetic variants associated with pharmacologic phenotypes. The availability of extensive genotype data for many panels of LCLs derived from individuals of diverse ancestry allows for the study of genetic variants contributing to interethnic and interindividual variation in susceptibility to drugs. Many genome-wide association studies for drug-induced phenotypes have been performed in LCLs, often incorporating gene-expression data. LCLs are also being used in follow-up studies to clinical findings to determine how an associated variant functions to affect phenotype. This review describes the most recent pharmacogenomic findings made in LCLs, including the translation of some findings to clinical cohorts. © 2012 Future Medicine Ltd.


Varughese S.,Section of Hematology Oncology | Jahangir K.S.,Section of Hematology Oncology | Simpson C.E.,Louisiana State University Health Sciences Center | Boulmay B.C.,Section of Hematology Oncology
American Journal of the Medical Sciences | Year: 2012

Lung cancer is the most common cause of cancer death for men and women worldwide. Nonsmall cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers. Systemic chemotherapy is a cornerstone of treatment in the management of stage IV NSCLC. First-line chemotherapy typically consists of a platinum-based treatment. The optimum approach to long-term treatment beyond 4 to 6 cycles of chemotherapy is still evolving. Second-line chemotherapy given at the time of disease progression has shown clear survival advantages when compared with best supportive care alone. With the recent increase in the number of active and more tolerable agents available to treat NSCLC, there is renewed interest in the role of continuation of antineoplastic agents (continuation maintenance) or switching to a different agent (switch maintenance) after first-line chemotherapy. This case-based review discusses the role of maintenance chemotherapy in the long-term management of advanced NSCLC. © 2012 Lippincott Williams & Wilkins.


Zahr A.A.,Section of Hematology Oncology | Aldin E.S.,Medstar Good Samaritan Hospital | Komrokji R.S.,H. Lee Moffitt Cancer Center and Research Institute | Zeidan A.M.,Yale University
Journal of Blood Medicine | Year: 2015

Myelodysplastic syndromes (MDS) represent a heterogeneous group of acquired clonal hematopoietic disorders characterized by peripheral blood cytopenias, paradoxical BM hypercellularity, ineffective hematopoiesis, and increased risk of leukemic transformation. Risk stratification, using different prognostic scores and markers, is at the core of MDS management. Deletion 5q [del(5q)] MDS is a distinct class of MDS characterized by the haploinsufficiency of specific genes, microRNAs, and proteins, which has been linked to increased sensitivity to the drug lenalidomide. Phase II and III clinical trials have demonstrated the efficacy of lenalidomide in improving clinical outcomes of patients with del(5q) MDS, including reduction in red blood cell transfusion requirements and improvements in quality of life. Lenalidomide has also demonstrated some activity in non-del(5q) lower-risk MDS as well as higher-risk MDS, especially in combination with other agents. In this paper, we review the pathogenesis of del(5q) MDS, the proposed mechanisms of action of lenalidomide, the major clinical trials that documented the activity of lenalidomide in different MDS populations, potential predictors of benefit from the drug and suggested mechanisms of resistance, and the use of combination strategies to expand the clinical utility of lenalidomide in MDS. © 2015 Abou Zahr et al.


Pinto N.,Section of Hematology Oncology | Pinto N.,University of Chicago | Dolan M.E.,Section of Hematology Oncology | Dolan M.E.,University of Chicago
Current Drug Metabolism | Year: 2011

In the field of pharmacogenetics, we currently have a few markers to guide physicians as to the best course of therapy for patients. For the most part, these genetic variants are within a drug metabolizing enzyme that has a large effect on the degree or rate at which a drug is converted to its metabolites. For many drugs, response and toxicity are multi-genic traits and understanding relationships between a patient's genetic variation in drug metabolizing enzymes and the efficacy and/or toxicity of a medication offers the potential to optimize therapies. This review will focus on variants in drug metabolizing enzymes with predictable and relatively large impacts on drug efficacy and/or toxicity; some of these drug/gene variant pairs have impacted drug labels by the United States Food and Drug Administration. The challenges in identifying genetic markers and implementing clinical changes based on known markers will be discussed. In addition, the impact of next generation sequencing in identifying rare variants will be addressed. © 2011 Bentham Science Publishers Ltd.


Eileen Dolan M.,Section of Hematology Oncology | O'Donnell P.H.,Section of Hematology Oncology | Gamazon E.,University of Chicago | Zhang W.,Section of Hematology Oncology | And 3 more authors.
Pharmacogenetics and Genomics | Year: 2010

OBJECTIVES: Clinical studies show that Asians (ASN) are more susceptible to toxicities associated with platinum-containing regimens. We hypothesized that studying ASN as an 'enriched phenotype' population could enable the discovery of novel genetic determinants of platinum susceptibility. METHODS: Using well-genotyped lymphoblastoid cell lines from the HapMap, we determined cisplatin and carboplatin cytotoxicity phenotypes (IC50s) for ASN, Caucasians (CEU), and Africans (YRI). IC50s were used in genome-wide association studies. RESULTS: ASN were most sensitive to platinums, corroborating clinical findings. ASN genome-wide association studies produced 479 single-nucleotide polymorphisms (SNPs) associating with cisplatin susceptibility and 199 with carboplatin susceptibility (P<10). Considering only the most significant variants (P<9.99×10), backwards elimination was then used to identify reduced-model SNPs, which robustly described the drug phenotypes within ASN. These SNPs comprised highly descriptive genetic signatures of susceptibility, with 12 SNPs explaining more than 95% of the susceptibility phenotype variation for cisplatin, and eight SNPs approximately 75% for carboplatin. To determine the possible function of these variants in ASN, the SNPs were tested for association with differential expression of target genes. SNPs were highly associated with the expression of multiple target genes, and notably, the histone H3 family was implicated for both drugs, suggesting a platinum-class mechanism. Histone H3 has repeatedly been described as regulating the formation of platinum-DNA adducts, but this is the first evidence that specific genetic variants might mediate these interactions in a pharmacogenetic manner. Finally, to determine whether any ASN-identified SNPs might also be important in other human populations, we interrogated all 479/199 SNPs for association with platinum susceptibility in an independent combined CEU/YRI population. Three unique SNPs for cisplatin and 10 for carboplatin replicated in CEU/YRI. CONCLUSION: Enriched 'platinum susceptible' populations can be used to discover novel genetic determinants governing interindividual platinum chemotherapy susceptibility. © 2010 Lippincott Williams & Wilkins, Inc.


PubMed | Section of Hematology Oncology, University of Oulu, Dana-Farber Cancer Institute, University of Chicago and Admescope Ltd.
Type: Journal Article | Journal: The Journal of biological chemistry | Year: 2016

The TET enzymes are members of the 2-oxoglutarate-dependent dioxygenase family and comprise three isoenzymes in humans: TETs 1-3. These TETs convert 5-methylcytosine to 5-hydroxymethylcytosine (5-hmC) in DNA, and high 5-hmC levels are associated with active transcription. The importance of the balance in these modified cytosines is emphasized by the fact that TET2 is mutated in several human cancers, including myeloid malignancies such as acute myeloid leukemia (AML). We characterize here the kinetic and inhibitory properties of Tets and show that the Km value of Tets 1 and 2 for O2 is 30 m, indicating that they retain high activity even under hypoxic conditions. The AML-associated mutations in the Fe(2+) and 2-oxoglutarate-binding residues increased the Km values for these factors 30-80-fold and reduced the Vmax values. Fumarate and succinate, which can accumulate to millimolar levels in succinate dehydrogenase and fumarate hydratase-mutant tumors, were identified as potent Tet inhibitors in vitro, with IC50 values 400-500 m. Fumarate and succinate also down-regulated global 5-hmC levels in neuroblastoma cells and the expression levels of some hypoxia-inducible factor (HIF) target genes via TET inhibition, despite simultaneous HIF stabilization. The combination of fumarate or succinate treatment with TET1 or TET3 silencing caused differential effects on the expression of specific HIF target genes. Altogether these data show that hypoxia-inducible genes are regulated in a multilayered manner that includes epigenetic regulation via TETs and 5-hmC levels in addition to HIF stabilization.

Loading Section of Hematology Oncology collaborators
Loading Section of Hematology Oncology collaborators