Journal of Blood Disorders & Transfusion

Breakpoint junctional site of KMT2A (MLL) rearrangements in acute leukemia: A brief review of cases

3^rd International Conference on Hematology & Blood Disorders

November 02-04, 2015 Atlanta, USA

Yenamandra A

Vanderbilt University Medical Center, USA

Posters-Accepted Abstracts: J Blood Disord Transfus

Abstract:

Introduction: Recurring non-random clonal cytogenetic changes have been identified in specific morphologic tumor types. In a multidisciplinary approach to patient care, Cytogenetics, Fluorescence in situ hybridization (FISH) and Chromosomal microarray (CMA) play a crucial role in contributing to diagnosis, prognosis and genotype-specific therapy decisions for clinicians in the management of hematological neoplasm. We report here two cases of leukemia with abnormal findings by Cytogenetics, FISH and copy number variation (CNV) with Affymetrix CytoScan HD Array. Case 1: A 11 year old male with pediatric B cell ALL was referred for increased lymphoblasts with 92% of CD19+ cells Cd10, CD13, CD20, CD33, CD34 partial+ and TdT+. The karyotype of this patient was identified as: 46, XY, t(4;11)(q21;q23)[4]/47, idem, +21[14]/46, XY. FISH revealed a rearrangement of KMT2A locus in 93.5% and 3 copies of the RUNX1 locus at 21q22 in 58% of cells confirming the presence of t(4;11) and +21. Case 2: A 50 year old male with monocytic differentiation, 87% blasts, NPM!-, FLT3-ITD, CEBPA-AML was referred for cytogenetics and FISH testing. He was identified with 46, XY, t(9;11)(p22;q23) in all the 20 cells and KMT2A (MLL) rearrangement in 85.5% of the cells. Affymetrix SNP array identified small genomic deletion or copy number variation at the breakpoint junction site of t(4;11) involving AFF1-KMT2A and t(9;11) translocation involving MLLT3-KMT2A genes. It is not clear at this point if genes with copy number breakpoints are represented at much higher level in cancer versus normal cells. It is also not clear if the size of these small deletions at junctional sites of translocations differs from patient to patient with similar translocations and/or differs between array platforms. These genes involved in recurrent translocations and or rearrangements are worthy of further studies.

Biography :

Email: ashwini.yenamandra@Vanderbilt.Edu