A t(8;9)(p22;p24)/PCM1-JAK2 translocation in a patient with myeloproliferative neoplasm and myeloid sarcoma: first report in Korea

Sustained Response to Ruxolitinib of Eosinophilia-Associated Myeloproliferative Neoplasm with Translocation t(8;9)(p21;p24)

The translocation t(8;9) produces the fusion gene PCM1-JAK2, resulting in the continuous activation of the JAK2 tyrosine kinase. Myelodysplastic/myeloproliferative neoplasms are the most common disease with t(8;9)/PCM1-JAK2. Individuals with this abnormality have similar features, and JAK2 kinase inhibitor (ruxolitinib) is an effective treatment of the condition. The long-term remission results of ruxolitinib are varied. It is important to determine the response to ruxolitinib. Here, we describe a patient who has been diagnosed with eosinophilia-associated myeloproliferative neoplasm with t(8;9)(p21;p24). This patient has achieved sustained response for >1 year since the administration of ruxolitinib.

OUP accepted manuscript

Background

This review summarizes the case studies of PCM1-JAK2 fusion tyrosine kinase gene-related neoplasia. Recommended treatment includes JAK2 inhibitors and hematologic stem cell transplantation (HSCT), although the small number of patients has limited study of their efficacy. Herein, we present all available cases in the current searchable literature with their demographics, diagnoses, treatments, and outcomes.

Methods

PubMed, ScienceDirect, Publons, the Cochrane Library, and Google were searched with the following terms: PCM1-JAK2, ruxolitinib and myeloid/lymphoid.

Results

Sixty-six patients (mean age = 50, 77% male) had an initial diagnosis of myeloproliferative neoplasm (MPN) in 40, acute leukemia in 21 and T-cell cutaneous lymphoma in 5. Thirty-five patients (53%) had completed 5-year follow-up. The 5-year survival for the MPN, acute myelogenous leukemia (AML), acute lymphocytic leukemia, and lymphoma groups are 62.7, 14.9%, 40.0%, and 100%, respectively. Too few patients have been treated with ruxolitinib to draw conclusions regarding its effect on survival while the 5-year survival for MPN patients with or without HSCT was 80.2% (40.3%-94.8%) versus 51.5% (22.3%-74.6%), respectively. The T-cell cutaneous lymphoma patients have all survived at least 7 years.

Conclusion

This rare condition may be increasingly detected with wider use of genomics. Ruxolitinib can yield hematologic and molecular remissions. However, HSCT is, at this time, the only potentially curative treatment. Useful prognostic markers are needed to determine appropriate timing for HSCT in patients with MPN. Patients presenting with acute leukemia have a poor prognosis.

Sequential allogeneic transplantation and ruxolitinib maintenance for a synchronous PCM1-JAK2 positive myeloid sarcoma and acute B-lymphoblastic leukemia

The translocation t(8;9)(p22;p24) results in the production of a chimeric PCM1-JAK2 fusion protein leading to the constitutive activation of the Janus Kinase 2 that renders this disease potentially sensitive to ruxolitinib. Here, we report an interesting case of PCM1-JAK2 myeloproliferative neoplasm evolving in myeloid sarcoma and B precursor ALL.

Diagnosis and Treatment of Myeloproliferative Neoplasms With PCM1-JAK2 Rearrangement: Case Report and Literature Review

Myeloproliferative neoplasm (MPN) with PCM1-JAK2 rearrangement is a rare disease with poor prognosis and lacks uniform treatment guidelines. Several studies confirmed the efficacy of ruxolitinib in hematological malignancies with PCM1-JAK2 fusion, but the efficacy is variable. Here, we report two patients diagnosed with MPN with PCM1-JAK2 fusion who were treated with ruxolitinib-based regimen, including the first case of ruxolitinib combined with pegylated interferon (Peg-IFN), and we conduct a literature review. We found that ruxolitinib combined with Peg-IFN is an effective treatment option in the case of poor efficacy of ruxolitinib monotherapy.

Response to tyrosine kinase inhibitors in myeloid neoplasms associated with PCM1-JAK2, BCR-JAK2 and ETV6-ABL1 fusion genes

We report on 18 patients with myeloid neoplasms and associated tyrosine kinase (TK) fusion genes on treatment with the TK inhibitors (TKI) ruxolitinib (PCM1-JAK2, n = 8; BCR-JAK2, n = 1) and imatinib, nilotinib or dasatinib (ETV6-ABL1, n = 9). On ruxolitinib (median 24 months, range 2-36 months), a complete hematologic response (CHR) and complete cytogenetic response (CCR) was achieved by five of nine and two of nine patients, respectively. However, ruxolitinib was stopped in eight of nine patients because of primary resistance (n = 3), progression (n = 3) or planned allogeneic stem cell transplantation (allo SCT, n = 2). At a median of 36 months (range 4-78 months) from diagnosis, five of nine patients are alive: four of six patients after allo SCT and one patient who remains on ruxolitinib. In ETV6-ABL1 positive patients, a durable CHR was achieved by four of nine patients (imatinib with one of five, nilotinib with two of three, dasatinib with one of one). Because of inadequate efficacy (lack of hematological and/or cytogenetic/molecular response), six of nine patients (imatinib, n = 5; nilotinib, n = 1) were switched to nilotinib or dasatinib. At a median of 23 months (range 3-60 months) from diagnosis, five of nine patients are in CCR or complete molecular response (nilotinib, n = 2; dasatinib, n = 2; allo SCT, n = 1) while two of nine patients have died. We conclude that (a) responses on ruxolitinib may only be transient in the majority of JAK2 fusion gene positive patients with allo SCT being an important early treatment option, and (b) nilotinib or dasatinib may be more effective than imatinib to induce durable complete remissions in ETV6-ABL1 positive patients.

Systematic review about etiologic association to the leukoerythroblastic reaction

BACKGROUND AND PURPOSE

Leukoerythroblastic reaction (LER) is characterized by the presence of immature erythroid cells and myeloid precursors (metamyelocytes, myelocytes, promyelocytes, myeloblasts, and blasts) as well as, exclusively in myelofibrotic disorders, teardrop cells in the peripheral blood (J Pathol Bacteriol, 42, 1936, 541; Semaine Med, 22, 1902, 373). Research on how to interpret LER and its meaning in clinical practice is scarce, and there is no consensus on the diagnostic criteria. We summarize the current evidence with the aim of clarifying the knowledge on this subject.

METHODS

We conducted a comprehensive search of the PubMed-MEDLINE, EMBASE and ELSEVIER databases, the Cochrane Library, Google Scholar, and medical journals to identify relevant papers.

RESULTS

Our search identified 425 papers, of which, 35 (11 trials and 24 case reports) ultimately met the inclusion criteria. These showed two principal groups of diseases associated with leukoerythroblastosis (LEB), corresponding to solid and hematological malignancies. The other etiologies, in order of frequency, were hemolytic diseases, infection, and others, while hemorrhage was only reported in the trials group.

CONCLUSION

The literature on LER is scarce and heterogeneous. The etiological factors of LER are diverse, and its presence in malignant disease is an indicator of disease progression and an adverse prognosis suggesting poor survival. In those cases where LER had neither hematological nor solid neoplasms, its manifestation, prognosis and its impact on our daily clinical practice are unknown.

Eosinophilia in acute myeloid leukemia: Overlooked and underexamined

The presence of eosinophilia in acute myeloid leukemia (AML) suggests an underlying core binding factor (CBF) lesion, a platelet derived growth factor (PDGFR) translocation, or another rare translocation (such as ETV6-ABL1). Each of these cytogenetic entities carries unique diagnostic, prognostic, and therapeutic implications. CBF AML is most common and as such, its treatment is more clearly established, consisting of intensive induction chemotherapy followed by cytarabine based consolidation. Due in large part to its intrinsic chemo-sensitivity, CBF AML is associated with relatively high rates of remission and survival. PDGFR mediated AML is comparatively rare, and as such, diagnostic and treatment paradigms are not as well defined. Early identification of PDGFR translocations is essential, as they confer profound imatinib sensitivity which may, in many instances, spare the need for chemotherapy. Prompt recognition of such lesions requires a strong index of suspicion, and as such these diagnoses are often initially overlooked. Unfortunately, many cases of PDGFR associated AML, particularly those with other concurrent cytogenetic abnormalities, demonstrate treatment emergent imatinib resistance. Such patients continue to present a challenge, even with the advent of novel tyrosine kinase inhibitors (TKIs). Patients with rare translocations such as ETV6-ABL1 are not well described however seem to follow an aggressive clinical course, with limited response to imatinib, and poor outcomes. This review examines the significance of eosinophilia in the context of AML, with respect to its presentation, pathology, and cytogenetics, and with special attention to appropriate evaluation and treatment.