Bone marrow ectopic expression of a non-coding RNA in childhood T-cell acute lymphoblastic leukemia with a novel t(2;11)(q11.2;p15.1) translocation

Chromosomal translocations play a crucial role in tumorigenesis, often resulting in the formation of chimeric genes or in gene deregulation through position effects. T-cell acute lymphoblastic leukemia (T-ALL) is associated with a large number of such rearrangements. We report the ectopic expression of the 3' portion of EST DA926692 in the bone marrow of a childhood T-ALL case showing a t(2;11)(q11.2;p15.1) translocation as the sole chromosome abnormality. The breakpoints, defined at the sequence level, mapped within HPS5 ( Hermansky Pudlak syndrome 5) intron 1 at 11p15.1, and DA926692 exon 2 at 2q11.2. The translocation was accompanied by a submicroscopic inversion that brought the two genes into the same transcriptional orientation. No chimeric trancript was detected. Interestingly, Real-Time Quantitative (RQ)-PCR detected, in the patient's bone marrow, expression of a 173 bp product corresponding to the 3' portion of DA926692. Samples from four T-ALL cases with a normal karyotype and normal bone marrow used as controls were negative. It might be speculated that the juxtaposition of this genomic segment to the CpG island located upstream HPS5 activated DA92669 expression. RQ-PCR analysis showed expression positivity in 6 of 23 human tissues examined. Bioinformatic analysis excluded that this small non-coding RNA is a precursor of micro-RNA, although it is conceivable that it has a different, yet unknown, functional role. To the best of our knowledge, this is the first report, in cancer, of the activation of a small non-coding RNA as a result of a chromosomal translocation

MYEOV gene overexpression in primary plasma cell leukemia with t(11;14)(q13;q32)

Primary plasma cell leukemia (pPCL) is an uncommon form of plasma cell dyscrasia, and the most aggressive of the human monoclonal gammopathies. The t(11;14)(q13;q32) rearrangement is the most common alteration in pPCL, promoting cyclin D1 (CCND1) gene overexpression caused by its juxtaposition with the immunoglobulin heavy locus chromosome region. The myeloma overexpressed (MYEOV) gene maps very close to the CCND1 gene on chromosome 11, but its overexpression is rarely observed in multiple myeloma. The present study describes a case of pPCL with t(11;14) characterized by a breakpoint on der(11), unlike the one usually observed. Droplet digital polymerase chain reaction analysis revealed overexpression of CCND1 and MYEOV. To the best of our knowledge, MYEOV gene overexpression has never been previously described in pPCL

A novel t(2;10)(q31;p12) balanced translocation in acute myeloid leukemia

We describe a case of acute myeloid leukemia M5 showing a balanced t(2;10)(q31;p12) translocation. This has never been described before as the sole cytogenetic abnormality in a bone marrow cell clone at onset. Using fluorescence <em>in situ</em> hybridization with properly designed bacterial artificial chromosome probes, we mapped the breakpoint regions on both derivative chromosomes 2 and 10:der(2) and der(10), respectively. The <em>MPP7</em> gene, disrupted by the breakpoint on chromosome 10, was juxtaposed upstream of both <em>HNRNA3</em> and <em>NFE2L2</em> genes on chromosome 2, without the formation of any fusion gene. Using real-time quantitative polymerase chain reaction, we tested the possible disregulation of any of the breakpoint-associated genes as a consequence of the translocation, but we found no statistically significant alteration. Considering the potential role of this clonal cytogenetic abnormality in leukemogenesis, we speculate that this translocation could have an impact on additional genes mapping outside the breakpoint regions. However, the limited amount of RNA material available prevented us from testing this hypothesis in this present case

Droplet Digital PCR Is a Reliable Tool for Monitoring Minimal Residual Disease in Acute Promyelocytic Leukemia

Nested RT-PCR (nPCR) and real-time quantitative PCR (qPCR) are well-established methods for monitoring minimal residual disease (MRD) in acute promyelocytic leukemia (APL). Despite their remarkable sensitivity and specificity, both methods have inherent limitations, such as qualitative MRD evaluation and relative quantification. Herein, we used droplet digital PCR (ddPCR) to monitor MRD in 21 APL patients and compared its performance with nPCR and qPCR. After assessing the limit of detection (LOD) for each technique on serial dilutions of PML-RARA bcr1 and bcr3 transcripts, a total of 48 follow-up samples were analyzed and the results compared. ddPCR showed good linearity and efficiency and reached an LOD comparable or even superior to nPCR and qPCR. When tested on primary samples, ddPCR exhibited a sensitivity and specificity of ≥95% and ≥91% for bcr1 and bcr3 transcripts and displayed a significant concordance with both techniques, particularly with nPCR. The peculiar advantage of ddPCR-based monitoring of MRD is represented by absolute quantification, which provides crucial information for the management of patients whose MRD fluctuates under the LOD of qPCR and is detectable, but not quantifiable, by nPCR. Our findings highlight ddPCR as a reliable complementary approach to monitor MRD in APL, and suggest its advantageous application, particularly for the molecular follow-up of patients at high risk of relapse