Flow Cytometric Immunobead Assay for Detection of BCR-ABL1 Fusion Proteins in Chronic Myleoid Leukemia: Comparison with FISH and PCR Techniques.

Chronic Myeloid Leukemia (CML) is characterized by a balanced translocation juxtaposing the Abelson (ABL) and breakpoint cluster region (BCR) genes. The resulting BCR-ABL1 oncogene leads to increased proliferation and survival of leukemic cells. Successful treatment of CML has been accompanied by steady improvements in our capacity to accurately and sensitively monitor therapy response. Currently, measurement of BCR-ABL1 mRNA transcript levels by real-time quantitative PCR (RQ-PCR) defines critical response endpoints. An antibody-based technique for BCR-ABL1 protein recognition could be an attractive alternative to RQ-PCR. To date, there have been no studies evaluating whether flow-cytometry based assays could be of clinical utility in evaluating residual disease in CML patients. Here we describe a flow-cytometry assay that detects the presence of BCR-ABL1 fusion proteins in CML lysates to determine the applicability, reliability, and specificity of this method for both diagnosis and monitoring of CML patients for initial response to therapy. We show that: i) CML can be properly diagnosed at onset, (ii) follow-up assessments show detectable fusion protein (i.e. relative mean fluorescent intensity, rMFI%>1) when BCR-ABL1IS transcripts are between 1-10%, and (iii) rMFI% levels predict CCyR as defined by FISH analysis. Overall, the FCBA assay is a rapid technique, fully translatable to the routine management of CML patients.

Epigenetic regulation in myelodysplastic syndromes: implications for therapy.

INTRODUCTION: Myelodysplastic syndromes (MDS), characterized by ineffective hematopoiesis and dysplasia in one or more lineages, produce life-threatening cytopenias and progress to acute myeloid leukemia (AML). Growing evidence suggests that targeting epigenetic mechanisms improves MDS/AML pathophysiology. AREAS COVERED: This review provides an understanding of studies investigating novel agents published up to January 2011 aimed at normalizing and monitoring the epigenetic profile of the MDS cancer cell. The authors discuss how non-intensive epigenetic therapy can 're-programme' gene expression patterns of abnormal hematopoiesis in MDS. Recently FDA-approved DNA-methyltransferase inhibitors, 5-azacytidine and 5-aza-2'-deoxycytidine or decitabine, represent frontline nonablative treatments, while combinations with histone deacetylase inhibitors show promising synergism in preclinical and Phase I/II trials in tumor suppressor gene re-expression and overall survival. Additional epigenetic mechanisms including non-encoding transcripts with inhibitory posttranscriptional regulatory functions, such as microRNAs, though not fully understood, present novel molecular and clinical implications in these disorders. EXPERT OPINION: Alongside current single-agent epigenetic regimens, combination therapies represent potentially effective options for intermediate-2 and high-risk MDS. Methylation profiles and gene mutation predictors provide promising areas of development for monitoring MDS disease progression and outcome, while targeting microRNA dysregulation represents an important therapeutic goal.

Lenalidomide in the treatment of chronic lymphocytic leukemia.

INTRODUCTION: insights into the role of the tumor microenvironment and of immune dysfunction in chronic lymphocytic leukemia (CLL) have opened the way for further augmenting the therapeutic armamentarium for CLL patients. In this respect, lenalidomide represents an exciting drug since it is able to eliminate CLL cells without immunosuppression. AREAS COVERED: mechanism of action and clinical trials of lenalidomide in CLL, and suggestions for its future utilization are reviewed. The most relevant papers and the meeting abstracts published up to July 2010 were used as sources for this review. This review will help readers understand the mechanism of action of lenalidomide and will provide a comprehensive summary regarding efficacy and safety of this drug in CLL patients. EXPERT OPINION: lenalidomide shows good activity against CLL. However, the toxicity profile is significant and can result in serious and potentially life-threatening side effects. Definitive data from ongoing trials will aid better definition of its status in CLL therapy. Moreover, clarification of the exact mechanism(s) of action in CLL will allow more precise use of lenalidomide and design of more efficacious combination therapies.

Janus kinase 2 inhibitors in myeloproliferative disorders.

IMPORTANCE OF THE FIELD: JAK2 is an obligatory kinase for the proliferation and differentiation of erythroid cells and megakaryocytes thus representing a relevant therapeutic target for agents that specifically inhibit its activity particularly in myeloproliferative disorders (MPD) harboring JAK2(V617F) mutations. AREAS COVERED IN THIS REVIEW: We discuss the physiopathology of the JAK2 signaling pathway and review clinical trials of JAK2 inhibitors for the treatment of MPD using papers and meeting abstracts published up to September 2010. WHAT THE READER WILL GAIN: This review helps in understanding the potential role of JAK2 inhibitors in MPD clinical trials and provides a comprehensive review regarding their efficacy and safety in these disorders. TAKE HOME MESSAGE: JAK2 inhibitors may prove to be useful only for suppressing disease manifestations. However, unlike drugs such as IFN which are capable of eliminating the malignant clone, JAK2 inhibitors are unable to eradicate the disease. In fact, results to date indicate that although these inhibitors reduce splenomegaly and alleviate constitutional symptoms irrespective of JAK2 mutational status, most have only a modest impact on the JAK2(V617F) allele burden. Considering the relevant risk of serious complications in patients undergoing splenectomy, these drugs could find a suitable indication in patients with myelofibrosis awaiting bone marrow transplantation.