An e6a2 BCR-ABL fusion transcript in a CML patient having an iliac chloroma at initial presentation

Atypical presentation of patients with chronic myeloid leukemia in chronic phase—Case report

The presence of the translocation t(9;22)(q34;q11), leading to the BCR::ABL1 fusion transcript, is the hallmark of chronic myeloid leukemia (CML). Nevertheless, atypical presentation at diagnosis can be challenging. However, although most patients with CML are diagnosed with the e13a2 or e14a2 BCR::ABL1 fusion transcripts, about 5% of them carry rare BCR::ABL1 fusion transcripts, such as e19a2, e8a2, e13a3, e14a3, e1a3, and e6a2. In particular, the e6a2 fusion transcript has been associated with clinically aggressive disease frequently presenting in accelerated or blast crisis phases. To date, there is limited evidence on the efficacy of front-line second-generation tyrosine kinase inhibitors for this genotype. Here, we report two patients, in whom the diagnosis of CML was challenging. The use of primers recognizing more distant exons from the common BCR::ABL1 breakpoint region correctly identified the atypical BCR::ABL1 e6a2 fusion transcript. Treatment with the second-generation tyrosine kinase inhibitor nilotinib was effective in our patient expressing the atypical e6a2 BCR::ABL1 fusion transcript.

Myeloid sarcoma: an uncommon presentation of myeloid neoplasms; a case series of 4 rare cases reported in a tertiary care institute

Myeloid sarcoma (MS) is a rare extramedullary neoplasm of myeloid cells, which can arise before, concurrently with, or following hematolymphoid malignancies. We report 04 such cases of MS, diagnosed in this institute over a period of 6 years, during various phases of their respective myeloid neoplasms/leukemias. These cases include MS occurring as a relapse of AML (Case 1), MS occurring as an initial presentation of CML (Case 2), MS occurring during ongoing chemotherapy in APML (Case 3), and MS presenting as a progression of MDS to AML (Case 4). In the absence of relevant clinical history and unemployment of appropriate immunohistochemical (IHC) studies, these cases have a high risk of being frequently misdiagnosed either as Non-Hodgkin’s Lymphoma (NHL) or small round cell tumors or undifferentiated carcinomas, which may further delay their management, making an already bad prognosis worse. This case series has been designed to throw light on the varied presentation of MS and the lineage differentiation of its neoplastic cells through the application of relevant IHC markers along with their clinical correlation.

A rare BCR-ABL1 transcript in Philadelphia-positive acute myeloid leukemia: case report and literature review

Background

Philadelphia (Ph) chromosome results from the reciprocal translocation t(9;22)(q34.1;q11.2) and is diagnostic for chronic myeloid leukemia (CML). However, this translocation is also found in acute lymphoid leukemia (ALL), as well as in rare cases of acute myeloid leukemias (AML). Most patients with CML harbor either the e13a2 or the e14a2 BCR-ABL fusion product, while a small subset of the cases expresses e1a2 or e19a2 transcripts. Moreover, several atypical BCR-ABL1 transcripts, beside the most common e1a2, e13a2 and e14a2, have been described, mainly in patients with CML. However, ALL and de novo AML may also carry BCR-ABL1 atypical transcripts which will confer a poor prognosis.

Case presentation

A 78-years old male was admitted at our hospital with clinical and laboratory features allowing to make the diagnosis of AML. No evidence of a preceding CML (splenomegaly or basophilia) was found. The karyotype on G-banded metaphases was 46,XY, t(9;22)(q34;q11). While the molecular analysis was ongoing, the patient started treatment based on hydroxyurea followed by 5-aza-2′-deoxycytidine. The molecular biology analysis revealed the simultaneous presence of the common p190 e1a2 and the rare e6a2 isoforms. Because of persistent pancytopenia and presence of blasts, according to the molecular data, he was then switched to tyrosine kinase inhibitors (TKIs) treatment. Nevertheless, after 2 months, the patient was still refractory to second line treatment dying because of a pulmonary infection.

Conclusion

The atypical p190 e6a2 transcript seems to be associated in AML with aggressive disease. TKI therapy alone does not seem to control the disease. Prompt observations on these patients carrying rare BCR-ABL1 transcripts may help to establish optimal treatment approaches on these aggressive BCR-ABL1 phenotypes in different setting of patients.

Chronic Myeloid Leukemia with b3a3 (e14a3) Fusion: A Rare BCR/ABL Rearrangement Presenting with Thrombocytosis - Does MTHFR Polymorphism Matter

Fusion of b2a2 is the most common BCR/ABL rearrangement in CML; however, absent a2 exons are very rare. We describe a case with Philadelphia-positive chronic myeloid leukemia (CML) with a very rare b3a3 (e14a3) BCR/ABL junction. To our knowledge, only 15 such cases of CML have previously been reported. These uncommon transcripts may be under-reported, since RT-PCR-based assays may fail to detect these fusions due to the location of the primers and probes used. We are reporting this case for the first time which presented with MTHFR mutation and significant thrombocytosis. There is very limited information on how this genotype expresses and responds to treatment, especially to tyrosine kinase inhibitors, as compared to classic CML. Also, the relationship between MTHFR mutation and CML is not clear, although studies have been done.

Successful treatment with allogeneic stem cell transplantation followed by DLI and TKIs for e6a2 BCR-ABL-positive acute myeloid leukaemia: A case report and literature review

RATIONALE

Patients with the e6a2 BCR-ABL transcript, 1 of the atypical transcripts, have been reported to have a poor prognosis, and allogeneic stem cell transplantation (ASCT) can be considered as additional therapy. However, long-term survival after ASCT for this disease is rare.

PATIENT CONCERNS

This report concerns a 55-year-old female patient with e6a2 BCR-ABL-positive acute myeloid leukemia including the outcome of ASCT followed by donor lymphocyte infusion (DLI).

DIAGNOSES

The breakpoint was confirmed by direct sequencing. Her minimal residual disease could be detected by nested reverse-transcription polymerase chain reaction using primers for the minor BCR-ABL (e1a2) transcript.

INTERVENTIONS

Treatment with tyrosine kinase inhibitors (TKIs) and ASCT followed by DLI.

OUTCOMES

Despite multiple cytogenetic and molecular relapses after ASCT, she remains in molecular remission at 46 months after ASCT.

LESSONS

This case indicates the efficacy of the combination of the graft-versus-leukemia effect and TKIs for e6a2 BCR-ABL-positive acute leukemia. When the Philadelphia chromosome with an unusual chromosomal breakpoint is suggested, we should clarify the breakpoint because that information can aid molecular assessments and decisions to provide an additional or alternative therapy.

Gold Nanoparticles for BCR-ABL1 Gene Silencing: Improving Tyrosine Kinase Inhibitor Efficacy in Chronic Myeloid Leukemia

Introduction of tyrosine kinase inhibitors for chronic myeloid leukemia treatment is associated with a 63% probability of maintaining a complete cytogenetic response, meaning that over 30% patients require an alternative methodology to overcome resistance, tolerance, or side effects. Considering the potential of nanotechnology in cancer treatment and the benefits of a combined therapy with imatinib, a nanoconjugate was designed to achieve BCR-ABL1 gene silencing. Gold nanoparticles were functionalized with a single-stranded DNA oligonucleotide that selectively targets the e14a2 BCR-ABL1 transcript expressed by K562 cells. This gold (Au)-nanoconjugate showed great efficacy in gene silencing that induced a significant increase in cell death. Variation of BCL-2 and BAX protein expression, an increase of caspase-3 activity, and apoptotic bodies in cells treated with the nanoconjugate demonstrate its aptitude for inducing apoptosis on K562 BCR-ABL1-expressing cells. Moreover, the combination of the silencing Au-nanoconjugate with imatinib prompted a decrease of imatinib IC₅₀. This Au-nanoconjugate was also capable of inducing the loss of viability of imatinib-resistant K562 cells. This strategy shows that combination of Au-nanoconjugate and imatinib make K562 cells more vulnerable to chemotherapy and that the Au-nanoconjugate alone may overcome imatinib-resistance mechanisms, thus providing an effective treatment for chronic myeloid leukemia patients who exhibit drug tolerance.

Current trends in molecular diagnostics of chronic myeloid leukemia

Nearly 1.5 million people worldwide suffer from chronic myeloid leukemia (CML), characterized by the genetic translocation t(9;22)(q34;q11.2), involving the fusion of the Abelson oncogene (ABL1) with the breakpoint cluster region (BCR) gene. Early onset diagnosis coupled to current therapeutics allow for a treatment success rate of 90, which has focused research on the development of novel diagnostics approaches. In this review, we present a critical perspective on current strategies for CML diagnostics, comparing to gold standard methodologies and with an eye on the future trends on nanotheranostics.