The activating mutations in JAK2 (including JAK2V617F) that have been described in patients with myeloproliferative neoplasms (MPNs) are linked directly to MPN pathogenesis. We developed R723, an ...orally bioavailable small molecule that inhibits JAK2 activity in vitro by 50% at a concentration of 2nM, while having minimal effects on JAK3, TYK2, and JAK1 activity. R723 inhibited cytokine-independent CFU-E growth and constitutive activation of STAT5 in primary hematopoietic cells expressing JAK2V617F. In an anemia mouse model induced by phenylhydrazine, R723 inhibited erythropoiesis. In a leukemia mouse model using Ba/F3 cells expressing JAK2V617F, R723 treatment prolonged survival and decreased tumor burden. In V617F-transgenic mice that closely mimic human primary myelofibrosis, R723 treatment improved survival, hepatosplenomegaly, leukocytosis, and thrombocytosis. R723 preferentially targeted the JAK2-dependent pathway rather than the JAK1- and JAK3-dependent pathways in vivo, and its effects on T and B lymphocytes were mild compared with its effects on myeloid cells. Our preclinical data indicate that R723 has a favorable safety profile and the potential to become an efficacious treatment for patients with JAK2V617F-positive MPNs.
We performed a retrospective population-based cohort study of acute myeloid leukemia (AML) in Miyazaki Prefecture, Japan. Over 6 years, we diagnosed 221 patients (211 adults and 10 children) with ...AML, indicating an incidence of AML in Miyazaki Prefecture of 3.2 per 100,000 per year. In 193 adult patients with non-acute promyelocytic leukemia (APL), the proportion of patients with myelodysplasia, unfavorable risk karyotypes, antecedent hematologic diseases, prior chemotherapy for other malignancies, and small proportion of blasts in the marrow was higher in patients ≥65 years, and patients with poor performance status (PS) and higher WBC counts at diagnosis were more prevalent among patients ≥75 years. One-third of the adult non-APL patients met the inclusion criteria usually applied in clinical trials: de novo AML, age ≤64 years with PS 0–2 and no key organ dysfunction. The 5-year overall survival (OS) rate of adult non-APL patients was 21.1 % (patients ≤64 years, 33.8 %; 65–74 years, 21.6 %; ≥75 years, 0 %). Multivariate analysis revealed that French-American-British subtypes M0, M6, and M7, poor PS (3, 4), unfavorable risk karyotypes, and higher WBC counts at diagnosis were independent adverse prognostic factors associated with OS. This analysis provides real world data.
Successful treatment of many patients with advanced cancer using antibodies against programmed cell death 1 (PD-1; also known as PDCD1) and its ligand (PD-L1; also known as CD274) has highlighted the ...critical importance of PD-1/PD-L1-mediated immune escape in cancer development. However, the genetic basis for the immune escape has not been fully elucidated, with the exception of elevated PD-L1 expression by gene amplification and utilization of an ectopic promoter by translocation, as reported in Hodgkin and other B-cell lymphomas, as well as stomach adenocarcinoma. Here we show a unique genetic mechanism of immune escape caused by structural variations (SVs) commonly disrupting the 3' region of the PD-L1 gene. Widely affecting multiple common human cancer types, including adult T-cell leukaemia/lymphoma (27%), diffuse large B-cell lymphoma (8%), and stomach adenocarcinoma (2%), these SVs invariably lead to a marked elevation of aberrant PD-L1 transcripts that are stabilized by truncation of the 3'-untranslated region (UTR). Disruption of the Pd-l1 3'-UTR in mice enables immune evasion of EG7-OVA tumour cells with elevated Pd-l1 expression in vivo, which is effectively inhibited by Pd-1/Pd-l1 blockade, supporting the role of relevant SVs in clonal selection through immune evasion. Our findings not only unmask a novel regulatory mechanism of PD-L1 expression, but also suggest that PD-L1 3'-UTR disruption could serve as a genetic marker to identify cancers that actively evade anti-tumour immunity through PD-L1 overexpression.
Dear Editor, Essential thrombocythemia (ET) is a myeloproliferative neoplasm (MPN) that primarily involves the megakaryocytic lineage, and is characterized by increased numbers of large, mature ...megakaryocytes in bone marrow as well as sustained thrombocytosis. Mutations in JAK2 or calreticulin (CALR) are present in about 50% and 25% of patients with ET, respectively, and these mutations are thought to drive MPN 1. CALR and JAK2 mutations are mutually exclusive in MPNs 1. Compared with patients with JAK2-mutated ET, patients with CALR-mutated ET have lower Hb levels and lower numbers of granulocytes, but higher numbers of platelets 2-6. The CALR-mutated patients also have a lower incidence of thrombosis during their clinical course. Genetic background such as race may influence the risk of thrombosis, and recent study reported that Japanese ET patients with JAK2 mutation had a higher cumulative incidence of thrombosis than those with CALR mutations, although the differences were not significant 6. Therefore, we analyzed the impact of JAK2 and CALR mutations on clinical features and thrombotic events in Japanese patients with ET. KCI Citation Count: 0
Background
Secondary central nervous system lymphoma (SCNSL) without extra-central nervous system (CNS) involvement is characterized by isolated secondary CNS relapse in malignant lymphoma patients. ...SCNSL is a rare disease, and no standard treatment has yet been established.
Patients and methods
To elucidate the clinical characteristics and outcomes of SCNSL, we retrospectively analyzed 12 patients (median age 67 years) in Miyazaki prefecture for the last 5 years.
Results
The initial histological diagnoses of the patients were diffuse large B-cell lymphoma (DLBCL), mantle-cell lymphoma, and adult T-cell lymphoma in 9, 2, and 1 patient, respectively. We focused on analysis of the 9 SCNSL cases originating from DLBCL. The locations of CNS relapse were the cerebral hemisphere, basal ganglia, and cerebellum in 7, 1, and 1 patient, respectively. Three patients were treated with high-dose methotrexate (HD-MTX) therapy; 4 with whole-brain radiation therapy (WBRTX); and 1 with both HD-MTX and WBRTX. The remaining patients were treated with rituximab. Partial remission was achieved in 6 out of 9 patients (67%); the other 3 patients (33%) did not respond to therapy. Median survival of the 9 patients with CNS relapse was 253 days; 6 of the 9 patients survived for more than 6 months. As of March 2011, 2 HD-MTX group patients but none of the WBRTX group patients were alive.
Conclusions
In this retrospective study, 6 of 9 patients with SCNSL originating from DLBCL survived for more than 6 months. Both HD-MTX and WBRTX had clinical benefits in the treatment of SCNSL.
Fibronectin (FN) plays important roles in the proliferation, differentiation, and maintenance of megakaryocytic-lineage cells through FN receptors. However, substantial role of FN receptors and their ...functional assignment in proplatelet-like formation (PPF) of megakaryocytes are not yet fully understood. Herein, we investigated the effects of FN receptors on PPF using the CHRF-288 human megakaryoblastic cell line, which expresses VLA-4 and VLA-5 as FN receptors. FN and phorbol 12-myristate 13-acetate (PMA) were essential for inducing PPF in CHRF-288 cells. Blocking experiments using anti-β1-integrin monoclonal antibodies indicated that the adhesive interaction with FN via VLA-4 and VLA-5 were required for PPF. PPF induced by FN plus PMA was accelerated when CHRF-288 cells were enforced adhering to FN by TNIIIA2, a peptide derived from tenascin-C, which we recently found to induce β1-integrin activation. Adhesion to FN enhanced PMA-stimulated activation of extracellular signal-regulated protein kinase 1 (ERK1)/2 and enforced adhesion to FN via VLA-4 and VLA-5 by TNIIIA2-accelerated activation of ERK1/2 with FN plus PMA. However, c-Jun amino-terminal kinase 1 (JNK1), p38, and phosphoinositide-3 kinase (PI3K)/Akt were not stimulated by FN plus PMA, even with TNIIIA2. Thus, the enhanced activation of ERK1/2 by FN, PMA plus TNIIIA2 was responsible for acceleration of PPF with FN plus PMA.
Cytogenetic abnormalities were often observed in primary myelofibrosis patients. The presence of specific cytogenetic abnormalities, such as sole abnormalities of chromosome 13q−, 20q−, or −7/7q−, is ...reported to have the influence on the prognosis of primary myelofibrosis. We analyzed the data from the prospective survey of Japanese primary myelofibrosis patients which was conducted from 1999 to clarify the impact of cytogenetic abnormalities on the prognosis of primary myelofibrosis. A total of 202 primary myelofibrosis patients had the cytogenetic and the prognostic data. Eighty (40%) out of 202 cases had cytogenetic abnormalities, and an association was evident for platelet counts. Although the presence of an abnormal karyotype did not affect the prognosis, primary myelofibrosis patients with cytogenetic abnormalities other than 13q− and 20q− showed an inferior prognosis compared to patients with a normal karyotype or sole 13q− or 20q− abnormalities. Patients with an unfavorable cytogenetic profile (abnormal cytogenetics other than 13q− or 20q−) also had a greater tendency to transform to leukemia than patients with a favorable cytogenetic profile (normal cytogenetics, sole abnormalities of either chromosome 13q−, or 20q−). Abnormal cytogenetics other than 13q− or 20q− in primary myelofibrosis patients has the poor prognostic effect for both survival and the risk of leukemic transformation.
Activation of the JAK-STAT pathway by driver mutations of JAK2, CALR or MPL is the pathogenesis of myeloproliferative neoplasms (MPN). Mutations in epigenetic regulators that often coexist with ...driver mutations reinforce the function of MPN initiating cells and support MPN onset and maintenance. In myelofibrosis patients, JAK2 inhibitors exerted an innovative therapeutic effect on splenomegaly and constitutional symptoms, but had minimal effects on the JAK2V617F allele burden. Epigenetic abnormalities may be a good target for novel therapeutic strategies aiming to induce molecular remission in myelofibrosis patients. New information obtained by next-generation sequencing technologies would greatly contribute to elucidation of the mechanisms underlying MPN onset, progression and leukemic transformation.
TET2 Mutation in Adult T-Cell Leukemia/Lymphoma Kazuya Shimoda; Kotaro Shide; Takuro Kameda ...
Journal of Clinical and Experimental Hematopathology,
12/2015, Volume:
55, Issue:
3
Journal Article
Peer reviewed
Loss-of-function of ten-eleven translocation-2 (TET2) is a common event in myeloid malignancies, and plays pleiotropic roles, including augmenting stem cell self-renewal and skewing hematopoietic ...cells to the myeloid lineage. TET2 mutation has also been reported in lymphoid malignancies; 5.7-12% of diffuse large B-cell lymphomas and 18-83% of angioimmunoblastic T-cell lymphomas had TET2 mutations. We investigated TET2 mutations in 22 adult T-cell leukemia/lymphoma (ATLL) patients and identified a missense mutation in 3 cases (14%). TET2 mutation occurred in a number of ATLL patients and was likely involved in their leukemogenesis.
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