The myelodysplastic syndromes (MDS) comprise a heterogenous group of myeloid disorders with a highly variable disease course. Diagnostic criteria to better stratify patients with MDS continue to evolve, based on morphology, cytogenetics, and the presence of cytopenias. More accurate classification of patients will allow for better treatment guidance. Treatment encompasses supportive care, treatment of anemia, low-intensity therapy, and high-intensity therapy. This portion of the guidelines focuses on diagnostic classification, molecular abnormalities, therapeutic options, and recommended treatment approaches.
Chronic lymphocytic leukemia (CLL) is a biologically heterogeneous illness with a variable clinical course. Loss of chromosomal material on chromosome 13 at cytoband 13q14 is the most frequent genetic abnormality in CLL, but the molecular aberrations underlying del13q14 in CLL remain incompletely characterized. We analyzed 171 CLL cases for loss of heterozygosity and subchromosomal copy loss on chromosome 13 in DNA from fluorescence-activated cell sorting-sorted CD19 + cells and paired buccal cells using the Affymetrix XbaI 50k SNP array platform. The resulting highresolution genomic maps, together with array-based measurements of expression levels of RNA in CLL cases with and without del13q14 and quantitative PCR-based expression analysis of selected genes, support the following conclusions: (a) del13q14 is heterogeneous and composed of multiple subtypes, with deletion of Rb or the miR15a/miR16 loci serving as anatomic landmarks, respectively; (b) del13q14 type Ia deletions are relatively uniform in length and extend from breakpoints close to the miR15a/miR16 cluster to a newly identified telomeric breakpoint cluster at the f50.2 to 50.5 Mb physical position; (c) LATS2 RNA levels are f2.6-fold to 2.8-fold lower in cases with del13q14 type I that do not delete Rb, as opposed to del13q14 type II or all other CLL cases; (d) PHLPP RNA is absent in f50% of CLL cases with del13q14; and (e) f15% of CLL cases display marked reductions in miR15a/miR16 expression that are often but not invariably associated with bi-allelic miR15a/miR16 loss. These data should aid future investigations into biological differences imparted on CLL by different del13q14 subtypes.
Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world and remains incurable with conventional therapies. Patients with relapsed or resistant CLL have a significantly shortened lifespan. MDM2 inhibitors have been developed and may have significant potential in the treatment of CLL. Clinical development of these compounds would be aided through knowledge of molecular predictors of activity. To understand determinants of sensitivity or resistance to MDM2 inhibitor therapy in CLL, we comprehensively analyzed a large cohort of CLL patient-derived samples for response to MDM2 inhibition and correlated these responses with clinically important biomarkers. Furthermore, we employed high-density single nucleotide polymorphism (SNP) arrays to analyze genomewide changes of copy number and allele status, including that of p53. The results of these studies conclusively demonstrate that p53 status is the major determinant of response to MDM2 inhibitors in CLL. Additional defects in the p53 regulatory cascade do not appear operational in this leukemia. Further, we identify a novel subgroup of patients with CLL with early progressive disease that appears particularly sensitive to MDM2 inhibitor treatment. These data provide definitive evidence for target-specific and predictive activity and a rationale to proceed with this potentially important class of compounds in the treatment of CLL. IntroductionChronic lymphocytic leukemia (CLL) is the most common form of adult leukemia in the Western world, and is characterized by a highly variable clinical course. 1,2 Treatment of CLL is reserved for symptomatic patients or patients in advanced clinical stage. Despite improvements in response rates using chemoimmunotherapy combinations, CLL remains incurable, and patients refractory to fludarabine or patients who have suffered multiple disease relapses have a poor outlook. [3][4][5] Therefore, novel therapeutics are needed to advance the outlook for afflicted patients.Inhibitors of murine double minute 2 (Mdm2) represent a novel therapeutic approach. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] In cells with functional p53, the p53 activity is primarily inhibited through direct and tonic interaction with the MDM2 protein. [20][21][22] Treatment of various tumor cells with inhibitors of the MDM2-p53 interaction results in rising p53 levels and subsequent induction of cell-cycle arrest and apoptosis. For poorly understood reasons, nonmalignant cells appear relatively resistant to MDM2 inhibition. 23,24 In CLL, in contrast to many solid tumors, p53 is mutated in only about 10% of patients at presentation and in 10% to 30% of patients with pretreated disease. [25][26][27][28] Thus, small-molecule inhibitors that block the MDM2-p53 interaction could represent a new therapeutic strategy for the treatment of most patients with CLL.Human cancers are biologically heterogeneous and respond nonuniformly to therapeutic intervention. Therefore, understanding the molecular mechanisms underlying cancer susceptibili...
SummaryPatients with acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS) may respond to treatment with epigenetic-modifying agents. Histone deacetylase inhibitors may synergize with hypomethylating agents. This phase 1 dose-escalation study was designed to determine the maximum tolerated dose, recommended phase 2 dose, safety and tolerability of vorinostat plus decitabine in patients with relapsed/refractory AML, newlydiagnosed AML, or intermediate-to high-grade MDS. Thirty-four patients received concurrent therapy with decitabine plus vorinostat and 37 received sequential therapy with decitabine followed by vorinostat. Twenty-nine patients had relapsed/refractory AML, 31 had untreated AML and 11 had MDS. The target maximum administered dose (MAD) of decitabine 20 mg/m 2 daily for 5 d plus vorinostat 400 mg/d for 14 d was achieved for concurrent and sequential schedules, with one dose-limiting toxicity (Grade 3 QTc prolongation) reported in the sequential arm. Common toxicities were haematological and gastrointestinal. Responses were observed more frequently at the MAD on the concurrent schedule compared with the sequential schedule in untreated AML (46% vs. 14%), relapsed/refractory AML (15% vs. 0%) and MDS (60% vs. 0%). Decitabine plus vorinostat given concurrently or sequentially appears to be safe and well-tolerated. Concurrent therapy shows promising clinical activity in AML or MDS, warranting further investigation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.