Clinical Leukemia最新文献

Allogeneic stem cell transplantation (ASCT) is the only curative treatment option for patients with myelodysplastic syndrome (MDS). High 1-year ASCT mortality and relapse rates have necessitated the development of novel therapies to improve clinical outcomes. Recently, 5-azacitidine, a DNA hypomethylating agent, was reported to be used for graft salvage in patients undergoing cytogenetic relapse after ASCT. We report a similar case of graft salvage and maintenance after transplantation in an MDS patient using decitabine, another DNA hypomethylating agent known to induce cytogenetic remissions with a manageable side effect profile.

Bone marrow transplantation is the treatment of choice for some patients with acute myeloid leukemia and myelodysplastic syndrome (MDS). Patients with high-risk disease, such as those with MDS, in second (or subsequent) complete remission or those with poor-risk cytogenetics will benefit the most from this approach. With current transplantation techniques, outcomes have improved over recent years. Although relapse and graft-versus-host disease still are important problems faced by these patients, novel approaches have been developed to decrease the risk of complications, with excellent results.

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML). APL is characterized by specific genetic abnormality t(15;17), which results in fusion between the promyelocytic leukemia (PML) gene and the retinoic acid receptor-α (RARα). We describe the case of a 4-year-old boy who was admitted to hospital with severe infection of the oropharynx due to a peritonsillar abscess, along with hepatomegaly and splenomegaly. The initial laboratory tests showed a condition compatible with AML. The cytologic morphology, cytochemistry, and immunophenotyping were compatible with the AML M3 variant but with normal karyotype, fluorescence in situ hybridization and polymerase chain reaction (PCR) negative for t(15;17), and PCR negative for t(11;17). There was resistance to the initial chemotherapy, but the patient experienced an excellent result from nonrelative umbilical cord transplantation. The case represents an atypical situation of AML with promyelocytic characteristics and normal cytogenetics showing a poor prognosis that responded only to bone marrow transplantation.

Progressive multifocal leukoencephalopathy (PML) is a lethal degenerative disorder of the central nervous system caused by reactivation of latent polyomavirus JC in the immunosuppressed host. Although the condition is most prevalent among individuals with HIV, it also occurs in association with other diseases and therapies that compromise immune function, including lymphoproliferative disorders (LPDs) treated with chemotherapy. Herein, the clinical course of an individual with chronic lymphocytic leukemia who developed PML after treatment with fludarabine, cyclophosphamide, and rituximab is described. The report highlights diagnostic challenges posed by nonspecific neurologic symptoms and radiographic findings that can be associated with PML. The ensuing discussion describes important discoveries that have contributed to the understanding of PML, clinical and diagnostic characteristics of the disease, specific features of LPD-associated PML, and treatment strategies for this condition.

Emerging diagnostic and therapeutic developments give insight into the heterogeneous disease biology of acute myeloid leukemia (AML) and provide valuable prognostic information regarding response to therapies and targets for investigational treatments. Our understanding of AML has evolved from morphologic and cytochemical distinctions to cytogenetics-based classification systems. The most recent evolutionary step has been the recognition of the prognostic importance of pathobiologic variations, such as in FLT3, NPM, and c-Kit; and of clinical disease features, particularly age, de novo versus secondary disease, and remission status. Therapies designed to reverse or inhibit the mechanisms that appear to cooperate in the AML pathobiologic pathway have been developed, including those that target Bcl-2, Ras, hypermethylation, heat shock protein, multidrug resistance efflux pumps, tyrosine kinase activation, histone deacetylation, and FLT3. Despite this progress, clinical features still serve as the platform for entry into clinical trials of novel agents. As the driving mechanisms of leukemia pathogenesis become further defined, and the inhibition of said mechanisms at a molecular level are correlated to clinical response, future studies should enroll patients on the basis of these molecular features, perhaps in isolation of clinical features, as variables such as age and secondary disease are intermediate markers for underlying pathobiology.

Focusing on the pervasive role of microRNAs (miRNAs), we review the multiple steps of malignant transformation, outlining the common hallmarks of tumorigenesis: self-sufficiency in growth signals, insensitivity to growth-inhibitory signals, evasion of apoptosis, limitless replicative potential, sustained angiogenesis, and tissue invasion and metastasis. For each of these traits, we provide examples of miRNA contribution to the acquisition of a malignant phenotype. Finally, through an overview of the remarkable ability of miRNAs to regulate entire pathwaysas a result of the multiplicity of their targets, we highlight the attractive potential of developing miRNAtargeted therapies, which should affect all the aspects of tumorigenesis.

Advances in understanding of the molecular basis of acute myeloid leukemia (AML) are finally beginning to allow tailoring of therapy for patients based on relapse risk. Although remission-induction therapy for most patients today remains predominantly “one-fits-all” cytarabine-based chemotherapy, postremission treatments are becoming more individualized based on cytogenetic or molecular markers of disease. Successive cooperative group trials over the past decade have helped to clarify a role for allogeneic hematopoietic stem cell transplantation (HSCT) for patients with AML in first remission based on cytogenetic risk stratification. More recently, molecular risk stratification has also been helpful in identifying patients who benefit from early transplantation. Herein, we review the current state of allogeneic and autologous HSCT in AML, discuss the role for transplantation in patients with normal-karyotype leukemia, and provide practical recommendations for postremission strategies for AML in first complete remission. We also discuss the role for HSCT in advanced AML, for patients lacking suitable donors, and in older adults with reduced-intensity conditioning.