Chronic myeloid leukemia patient with co-occurrence of BCR-ABL junction and JAK2 V617F mutation

Is very high platelet count always associated with essential thrombocythemia? An unusual presentation in a child

Myeloproliferative neoplasms are rare in childhood. They are categorized as Philadelphia chromosome-positive and Philadelphia chromosome-negative. Chronic myeloid leukemia (CML) is the most common myeloproliferative disease in which the Philadelphia chromosome is detected as a result of BCR-ABL rearrangements. In others, the most common genetic abnormality is JAK2V617F mutation. The coexistence of these 2 abnormalities in CML is unexpected, and rare cases have recently been reported in adults. We present a child who had a very high platelet count in which we found this coexistence. The clinical presentation, laboratory findings, management, and prognosis of this coexistence is challenging in such a rare condition.

Chronic myeloid leukemia (CML) evolves from Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) with unexpected frequency

Myeloproliferative neoplasms (MPN) are chronic clonal disorders characterized by overproduction of myeloid-lineage blood cells and potential risk of evolution to acute myeloid leukemia (AML). Chronic myeloid leukemia (CML) is distinct from other MPNs in that its pathophysiology stems from the BCR-ABL fusion protein of the Philadelphia chromosome (Ph +). Though there are known cases of Ph- and Ph + MPNs coexisting in a single patient, overall prevalence has never been quantified in a prospective cohort. Here, we review our center's MPN registry, which shows 0.6% of Ph- MPN patients later developed CML. This development occurred no less than 10 and up to 36 years after Ph- MPN diagnosis. This rate of chronic transformation exceeds what is expected, as the incidence of CML in the United States is 2 per 100,000 people-years. The probability of this CML case rate in an average-risk population is less than 0.001%, suggesting there are shared risk factors between Ph- and Ph + MPNs. We speculate that these risk factors may include exposures, genetic predispositions, or be inherent to disease biology. Abrupt-onset leukocytosis heralded post-MPN CML in all cases here and suggests this salient clinical feature should trigger hematologists to consider this diagnosis and perform appropriate testing.

Co-existence of BCR-ABL and JAK2V617F mutation in resistant chronic myeloid leukemia in the imatinib era: Is there a correlation?

INTRODUCTION

Diagnoses of myeloproliferative disorder is based on molecular marker. Chronic Myeloid Leukemia and Myeloproliferative neoplasms were considered mutually exclusive and co-existence of BCR/ABL1 and JAK2 mutation is a rare phenomenon.

CASE REPORT

Here, we present two cases of co-existence of BCR-ABL and JAK2V617F positivity. We characterize the course of the disease, mainly the minimal residual disease.Management and outcome: The two cases was initially managed as Chronic Myeloid Leukemia and treated by TKI inhibitors. The first one was diagnosed in 2010. He started the first line of TKI, and then switched to second line without obtaining a major molecular response. Hence he was tested for JAK2V617F mutation and positivity was diagnosed. The second patient showed Chronic Myeloid Leukemia phenotype with coexistence of BCR/ABL1 and JAK2 mutation at diagnosis. Molecular monitoring reveals a high BCR-ABL1 transcript level (20%) at the last follow-up (12 months).

DISCUSSION

Ours results highlight that JAK2V617F/BCR-ABL double positivity may be a potential marker of resistance in Chronic Myeloid Leukemia and clonal molecular analysis is mandatory to elucidate the mechanism. Moreover, the combination of JAK and TKI inhibitors might be effective and potentially be guided by molecular monitoring of minimal residual disease.

JAK2 expression is correlated with the molecular and clinical features of breast cancer as a favorable prognostic factor

Janus kinases are a family of non-receptor tyrosine kinases involved in autoimmune diseases and malignancies. In breast cancer, the immune related role of JAK2 remains unclear. We aimed to investigate its role at transcriptome level and its relationship with the clinical outcome of breast cancer. This study enrolled a total of 2994 breast cancer samples with transcriptome data, including 1090 samples from The Cancer Genome Atlas (TCGA) and 1904 from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). JAK2 expression was significantly upregulated in both PR positive group (P < 0.01) and HER2 negative group (P < 0.01), and was correlated with American Joint Committee on Cancer (AJCC) stage and tumor malignancies of breast cancer. Functional enrichment analysis revealed that genes correlated with JAK2 were mainly involved in essential functions associated with immune response. Intriguingly, we investigated the association between JAK2 and immune modulators in pan-cancer, JAK2 expression was positively correlated with most of these immune modulators. In clinical aspect, higher expression of JAK2 was an independent indicator of favorable prognosis in breast cancer patients. The expression of JAK2 is tightly related to the pathology and molecular pathology of breast cancer, and synergistic with other checkpoint members thereby playing a specific role in regulating tumor immune microenvironment. To our knowledge, this is the largest and most comprehensive study characterizing the expression pattern of JAK2 and its special immune functions together with its prognostic values in breast cancer. These findings might shed novel sights for future research in cancer immunotherapy by targeting immune checkpoint molecules.

Co-existence of mutations in myeloproliferative neoplasms and their clinical significance: a prognostic approach

OBJECTIVE

Myeloproliferative neoplasms (MPNs) are a group of clonal hematopoietic stem cell disorders that may occur after one or more mutations in hematopoietic progenitor cells. In this study, we will review the co-existence of mutations (especially dual mutations) in MPNs and its effect on the prognosis of patients.

METHODS

To find relevant published papers, we systematically searched six major international indexing databases, namely PubMed/Medline, EmBase, Cochrane central, ISI web of science, and Scopus from Feb. 2000 until Jan. 2020. We included the following keywords in the analyzes: Myeloproliferative Disorders, Mutation, Co-existence of Mutations, Acute myeloid leukemia.

RESULTS

Co-existence of several mutations in MPNs is mainly associated with a poor prognosis compared with the unimutated MPN disorders. There are several effective factors such as sequence of mutations, incidence of mutations in one cell or different cells, mutation, and MPN type.

CONCLUSION AND EXPERT COMMENTARY

It seems that monitoring the status of mutations in MPNs and recognizing the co-existence of mutations (especially dual mutations) in order to determine prognosis and possibility of progression to acute form of leukemia can lead to the prediction of prognosis in MPN patients as well as establishment of better and more reliable therapeutic strategies for patients.

Concurrent JAK2-Positive Myeloproliferative Disorder and Chronic Myelogenous Leukemia: A Novel Entity? A Case Report With Review of the Literature

JAK2 V617F mutation and BCR-ABL translocation have been considered to be mutually exclusive. However, many cases where both hits coexisted have been reported. We have personally managed a case too. We believe this hybrid entity is underdiagnosed. Thus, we decided to shed light on this "double hit" disease to improve its diagnosis and optimize its treatment. We reviewed the English literature in PubMed since JAK2 discovery. We found 33 cases reported so far. We summarized patient characteristics and analyzed possible interactions between JAK2 and BCR-ABL clones.

Emergence of BCR-ABL1 Chronic Myeloid Leukemia in a JAK2-V617F Polycythemia Vera

Emergence of a new chronic myeloid neoplasm in the setting of a previous one, or their concomitant appearance seems to be a rare event, but plenty of cases have been reported. We describe the case of a patient with JAK2-V617F polycythemia vera, which looses JAK2 clone and develops overt BCR-ABL1 chronic myeloid leukemia after 6 years. Once treatment with tyrosine kinase inhibitors controls BCR-ABL1 clone, JAK2 clone arises again. In this report, we review the literature and discuss the clonal relationship of this event in light of the new molecular data.

Molecular analysis of V617F mutation in Janus kinase 2 gene of breast cancer patients

BACKGROUND

Breast cancer is a multifactorial disease with the highest frequency in females. Genetic and environmental factors can cause mutation in several genes like tyrosine kinase, JAK2 gene which may initiate cancer. Molecular analysis of mutations in the JAK2 gene along with determination of environmental, clinical and haematological risk factors associated with breast cancer patients is need of hour to improve patient's healthcare. Somatic JAK2 valine-to-phenylalanine (617 codon) mutation is one of the widely prevalent mutations.

METHODS

Blood was collected from seventy breast cancer patients after their consent. The questionnaire included risk factors, age group, locality, number of children, tumor type, family history, time of initial diagnosis, no of cycles/month, water conditions and exposure to radiations. Molecular analysis were carried out from genomic DNA using Sanger sequencing and allele-specific PCR to check the V617F point mutation.

RESULTS

The breast cancer risk factors includes unfiltered water (68.57%), urban (58.57%), menopause (55.71%), family history of cancer (18.57%), tumor grades (II, 37.14% and III, 35.71%), consanguineous marriages (44.28%) and having more than 3-4 children (45.71%). Prevalence of breast cancer was higher after the age of 35 and maximum at 35-50. In allele-specific PCR of 70 patients, 25 patients were wild type (229 bp), 25 patients were with partially deleted gene (200 bp), and 20 patient had shown no or less than 40 bp size fragments. In Sanger's sequencing of 70 BC cases, 18% were found to be positive for V617F point mutation, including 6 homozygous (T/T) and 7 heterozygous (G/T) mutations at nucleotide position 1849 in exon 14 of the JAK2 gene.

CONCLUSIONS

Environmental and clinical risk factors were associated with breast cancer which can be overcome by improving awareness of associated risks, health facilities and reducing stress.

Coexistence of breakpoint cluster region-Abelson1 rearrangement and Janus kinase 2 V617F mutation in chronic myeloid leukemia: A case report

BACKGROUND

The Janus kinase 2 (JAK2) V617F mutation is common in patients with breakpoint cluster region-Abelson1 (BCR-ABL1)-negative myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and primary myelofibrosis, but is rarely detected in BCR-ABL1-positive chronic myeloid leukemia (CML) patients. Here, we report a CML patient with both a BCR-ABL1 rearrangement and JAK2 V617F mutation.

CASE SUMMARY

A 45-year-old Chinese woman was admitted to our department with a history of significant thrombocytosis for 20 d. Color Doppler ultrasound examination showed mild splenomegaly. Bone marrow aspiration revealed a karyotype of 46, XX, t(9;22)(q34;q11.2) in 20/20 metaphases by cytogenetic analysis, rearrangement of BCR-ABL1 (32.31%) by fluorescent polymerase chain reaction (PCR) and mutation of JAK2 V617F (10%) by PCR and Sanger DNA sequencing. The patient was diagnosed with CML and JAK2 V617F mutation. Following treatment with imatinib for 3 mo, the patient had an optimal response and BCR-ABL1 (IS) was 0.143%, while the mutation rate of JAK2 V617F rose to 15%.

CONCLUSION

Emphasis should be placed on the detection of JAK2 mutation when CML is diagnosed to distinguish JAK2 mutation-positive CML and formulate treatment strategies.

Molecular genetics of BCR-ABL1 negative myeloproliferative neoplasms in India

Introduction

Over the past decade, we have moved on from a predominantly morphological and clinical classification of myeloproliferative neoplasms (MPN) to a more evolved classification that accounts for the molecular heterogeneity that is unique to this subgroup of hematological malignancies. This usually incorporates mutations in Janus kinase 2 (JAK2), MPL, and calreticulin (CALR) genes. In this manuscript, we report the frequency of these mutations in a cohort of Indian patients at a tertiary cancer center.

Materials and Methods

One hundred and thirty cases of MPN were included in this study. These cases were diagnosed and classified based on the World Health Organization 2008 criteria. JAK2 and MPL mutations were detected using high sensitivity allele-specific polymerase chain reaction using fluorescent labeled primers followed by capillary electrophoresis. A subset of JAK2 and CALR mutations were assessed using a fragment length assay.

Results

Among the MPN, we had 20 cases of polycythemia vera (PV), 34 cases of essential thrombocythemia (ET), and 59 of myelofibrosis (MF). JAK2, MPL, and CALR mutations were mutually exclusive of each other. Seventeen cases were categorized as MPN unclassifiable (MPN-U). JAK2p.V617F and MPL mutations were present in 60% (78 of 130) and 5.3% (7 of 130) of all MPN. All the PV cases harbored the JAK2 p.V617F mutation. A total of 23.8% (31 of 130) of patients harbored CALR mutations. CALR exon 9 mutations were detected in 60.8% (14 of 23) and 50% (5 of 10) of JAK2 and MPL negative MF and ET cases, respectively. MPN-U cases included three JAK2 p.V617F positive, two MPL p.W515 L, and 12 CALR positive cases. Ten different types of CALR indels (8 deletions and 2 insertions) were detected of which Type I and Type II mutations were the most common, occurring at a frequency of 45.1% (14 of 31) and 22.5% (7 of 31), respectively.

Discussion and Conclusion

We report frequencies of JAK2 p. V617F, MPL exon 10 and CALR mutations in 130 patients similar to those reported in western literature. These mutations carry not only diagnostic but also prognostic relevance.

Coexisting driver mutations in MPN: clinical and molecular characteristics of a series of 11 patients

OBJECTIVES

CML, PV, ET and PMF are so called classical MPN with distinct clinical phenotypes. The discovery of the BCR-ABL1 translocation and mutations in driver genes JAK2, MPL and CALR has provided novel insights in their pathogenesis. While these mutations are thought to be mutually exclusive, rare cases of MPN with coexisting driver mutations have been reported. However, little is known about the clinical, biological and molecular characteristics of these patients and the interaction of the neoplastic clones.

METHODS

We retrospectively studied 11 MPN patients with coexisting driver mutations (JAK2 V617F + BCR-ABL1: n = 8; CALR type 2 + BCR-ABL1: n = 1; JAK2 V617F + MPL W515: n = 1; JAK2 V617F + CALR type 1: n = 1). To assess possible associated molecular aberrations, we analysed DNA of six patients using NGS.

RESULTS

In four CML patients, decreasing BCR-ABL1 transcript levels with increasing JAK2 V617F allele burden under TKI were observed. This strongly suggests that the coexistence of driver mutations originates from two different clones growing independently. Additional somatic mutations were detected in 5 out of 6 (83%) patients affecting 4 different genes, confirming the heterogeneity of this study cohort. Suboptimal response to TKI was observed with a higher frequency (4/8 patients) than reported in conventional series of CML and the overall tolerance of treatment with hydroxyurea and/or imatinib in our series was poor.

CONCLUSION

Given the emergence of NGS in clinical practice, more similar cases will be identified in the coming years. The optimal treatment strategy for this rare group of patients is uncertain and toxicity of combination treatment may have to be considered.

Myeloproliferative neoplasms with concurrent BCR-ABL1 translocation and JAK2 V617F mutation: a multi-institutional study from the bone marrow pathology group

Myeloproliferative neoplasms arise from hematopoietic stem cells with somatically altered tyrosine kinase signaling. Classification of myeloproliferative neoplasms is based on hematologic, histopathologic and molecular characteristics including the presence of the BCR-ABL1 and JAK2 V617F. Although thought to be mutually exclusive, a number of cases with co-occurring BCR-ABL1 and JAK2 V617F have been identified. To characterize the clinicopathologic features of myeloproliferative neoplasms with concomitant BCR-ABL1 and JAK2 V617F, and define the frequency of co-occurrence, we conducted a retrospective multi-institutional study. Cases were identified using a search of electronic databases over a decade at six major institutions. Of 1570 patients who were tested for both BCR-ABL1 and JAK2 V617F, six were positive for both. An additional five patients were identified via clinical records providing a total of 11 cases for detailed evaluation. For each case, clinical variables, hematologic and genetic data, and bone marrow histomorphologic features were analyzed. The sequence of identification of the genetic abnormalities varied: five patients were initially diagnosed with a JAK2 V617F+ myeloproliferative neoplasm, one patient initially had BCR-ABL1+ chronic myeloid leukemia, while both alterations were identified simultaneously in five patients. Classification of the BCR-ABL1-negative myeloproliferative neoplasms varied, and in some cases, features only became apparent following tyrosine kinase inhibitor therapy. Seven of the 11 patients showed myelofibrosis, in some cases before identification of the second genetic alteration. Our data, reflecting the largest reported study comprehensively detailing clinicopathologic features and response to therapy, show that the co-occurrence of BCR-ABL1 and JAK2 V617F is rare, with an estimated frequency of 0.4%, and most often reflects two distinct ('composite') myeloproliferative neoplasms. Although uncommon, it is important to be aware of this potentially confounding genetic combination, lest these features be misinterpreted to reflect resistance to therapy or disease progression, considerations that could lead to inappropriate management.

Emergence of MPLW515 mutation in a patient with CALR deletion: Evidence of secondary acquisition of MPL mutation in the CALR clone

Myeloproliferative neoplasms are characterized by transduction pathway recognized as mutually exclusive molecular abnormalities such as BCR-ABL translocation, JAK2V617F or JAK2 exon 12 mutations, MPL w515, and CALR mutations. However, in some rare cases, associations of such mutations are found in 1 patient. This can be related to 2 pathologies (at least 2 different clones harboring 2 mutations) or associated mutations in 1 clone. We describe here such an association of CALR and MPL mutations in a patient harboring the second mutation in a subclone during the phenotypic evolution of the myeloproliferative neoplasms.

ASXL1 and JAK2V617F gene mutation screening in Iranian patients with chronic myeloid leukemia

AIM

In recent years, a few cases of chronic myeloid leukemia (CML) have been reported with both BCR-ABL and JAK2V617F mutations. Moreover, mutations in the additional sex comb-like 1 (ASXL1) gene were recently shown in various myeloid malignancies.There were no previous studies investigating the incidence of the ASXL1 and JAK2V617F mutations in Iranian patients with CML. Consequently, this study focuses on the analysis of these mutations in patients with CML.

METHODS

In total, 66 patients with a clinical diagnosis of CML were examined at the time of diagnosis. Thirty healthy subjects were checked as controls. Exon 12 of ASXL1 was amplified from genomic DNA and bidirectionally sequenced. We also performed JAK2V617F screening by amplification refractory mutation system-polymerase chain reaction and sequencing.

RESULTS

Mutations in the ASXL1 gene were found in five out of 66 CML patients (7.6%). We identified a novel variant (c.1968G > A, p.Asp656Asn) in one of the patients that has not been reported before. We also identified BCR-ABL and JAK2V617F mutations simultaneously in four patients (6%).

CONCLUSION

Our demonstration of ASXL1 mutation, a putative tumor suppressor gene, represents an important molecular abnormality in CML. We also showed that concomitant detection of BCR-ABL and JAK2V617F mutations has a relatively high incidence in Iranian patients.

Coexistence of p190 BCR/ABL Transcript and CALR 52-bp Deletion in Chronic Myeloid Leukemia Blast Crisis: A Case Report

We introduce a 78-year-old woman presented with thrombocytosis and high blast count who had a history of splenectomy. Her cytogenetic analysis revealed aberrant chromosomal rearrangements in different clonal populations harboring 46XX karyotype with t(9;22) (q34;q11). RT-PCR assay detected the e1a2 BCR-ABL translocation resulting from rearrangement of the minor breakpoint cluster region (m-bcr) in BCR gene. Subsequent evaluation of the disease showed calreticulin (CALR) 52-bp deletion as well as the absence of JAK2^V617F heterozygous mutation in granulocyte population of peripheral blood using allele-specific PCR and bi-directional DNA sequencing. To our knowledge, this is the first case of a patient initially diagnosed as p190 BCR-ABL transcript positive CML in blast crisis characterized by a 52-bp deletion in CALR gene.

Acute Lymphoblastic Leukemia in the Course of Polycythemia Vera: A Case Report and Review of Literature

INTRODUCTION

Polycythemia vera (PV) is one of the most common forms of myeloproliferative neoplasms. Acute myeloid leukemia secondary to PV is well reported, and the mechanism has been clarified to some extent. Only a limited number of cases have been reported about the development of acute lymphoblastic leukemia (ALL) in the course of PV, and the possible underlying mechanism has not been explored well.

CASE PRESENTATION

A 75-year-old patient who developed ALL 3 years after he was diagnosed with PV. The presence of remarkable splenomegaly, typical immunophenotyping of the peripheral blood and increased expression of serum fibrosis markers indicated the existence of extramedullary hematopoiesis which may ascribe to myelofibrosis. After the treatment of dosage-modulated chemotherapy, the patient got complete remission.

CONCLUSION

The JAK2 mutation may the underlying factor that contributes to the development of ALL, and the existence of MF may indicate the progression to post- polycythemic MF, which may be a risk factor for the accelerated transformation.

Oligogenic germline mutations identified in early non-smokers lung adenocarcinoma patients

OBJECTIVES

A polygenic model is commonly assumed for the predisposition to common cancers. With respect to lung cancer, Genome Wide Association Studies (GWAS) have identified three loci at 15q25, 5p15.33, and 6p21. However, the relative risks associated with alleles at these loci are low; in addition, the data are limited to smokers, and have not been quite reproducible.

MATERIALS AND METHODS

In order to investigate genetic susceptibility we have adopted an entirely novel patient selection strategy. First, we have selected for adenocarcinoma (ADCA) histology only; second, we have selected non-smokers; third we have selected patients who developed ADCA of lung before the age of 60 and who had an older unaffected sib: we have identified 31 such sib-pairs. Among them, we selected two patients with very early age at disease onset (37- and 49-years old), and having a healthy sibling available for genome comparison older than at least 7 years.

RESULTS

On germline DNA samples of four subjects of two such pairs we have carried out whole exome sequencing. Truncating mutations were detected in 8 'cancer genes' in one affected, and in 5 cancer genes in the other affected subject: but none in the two healthy sibs (p=0.0026). Some of these mutant genes (such as BAG6, SPEN and WISP3) are recognized as major cancer players in lung tumors; others have been previously identified in other human cancers (JAK2, TCEB3C, NELFE, TAF1B, EBLN2), in mouse models (GON4L, NOP58, and RBMX) or in genome-wide association studies (KIAA2018, ZNF311).

CONCLUSIONS

This study identifies for the first time in non-smokers with lung adenocarcinoma specific sets of germline mutations that, together, may predispose to this tumor.

Combination of the ABL kinase inhibitor imatinib with the Janus kinase 2 inhibitor TG101348 for targeting residual BCR-ABL-positive cells

Background

The ABL kinase inhibitor imatinib is highly effective in treating most, but not all, patients with chronic myeloid leukemia (CML). This is because residual CML cells are generally present in the bone marrow microenvironment and are refractory to imatinib. Hematopoietic cytokine receptor signaling is mediated by Janus kinases (JAKs) and their downstream transcription factor, signal transducer and activator of transcription (STAT). TG101348 (SAR302503) is an oral inhibitor of JAK2.

Methods

We investigated the efficacy of imatinib and TG101348 using the break point cluster region-c-Abelson (BCR-ABL)-positive cell line and primary CML samples wherein leukemia cells were protected by a feeder cell line (HS-5).

Results

Imatinib treatment resulted in partial inhibition of cell growth in HS-5-conditioned medium. Furthermore, combined treatment with imatinib and TG101348 abrogated the protective effects of HS-5-conditioned medium on K562 cells. Phosphorylation of Crk-L, a BCR-ABL substrate, decreased considerably, while apoptosis increased. In addition, the combined treatment of CD34-positive primary samples resulted in considerably increased cytotoxicity, decreased Crk-L phosphorylation, and increased apoptosis. We also investigated TG101348 activity against feeder cells and observed that STAT5 phosphorylation, granulocyte macrophage colony-stimulating factor, and interleukin 6 levels decreased, indicating reduced cytokine production in HS-5 cells treated with TG101348.

Conclusions

These results showed that JAK inhibitors may enhance the cytotoxic effect of imatinib against residual CML cells and that a combined approach may be a powerful strategy against the stroma-associated drug resistance of Philadelphia chromosome-positive cells.