Leukemia Research Reports最新文献

Near early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a rare hematologic malignancy, for which second line therapeutic options are limited. T-cell leukemias are also rarely associated with leukemia cutis, which is more often seen in leukemias of myeloid origin. We present the case of an adult male diagnosed with near ETP-ALL, with IDH2 and DNMT3A mutations, suggestive of a myeloid origin, and leukemia cutis. After the patient progressed on hyper-CVAD and nelarabine, we treated him with the BCL-2 inhibitor venetoclax and the hypomethylating agent decitabine. The regimen induced a rapid bone marrow response and resolution of the leukemia cutis.

Background

Systemic mastocytosis is a rare hematologic malignancy that leads to the accumulation of neoplastic mast cells in the bone marrow, visceral organs, and skin. Mutations in the receptor tyrosine kinase, KIT are seen in most patients with systemic mastocytosis. The most common mutation is a gain of function mutation in KIT D816V. Avapritinib is a highly selective KIT D816V inhibitor approved for the treatment of advanced systemic mastocytosis. Recent studies have also suggested that avapritinib is active across other KIT mutations located in exon 11 and exon 17.

Case Presentation

A 68 year old woman was referred for a history of lymphadenopathy and diarrhea and was ultimately found to have systemic mastocytosis with involvement in her bone marrow, gastrointestinal tract, liver, and spleen. The bone marrow biopsy reveled a novel KIT p.D816-N822delinsMIDSI mutation in exon 17. The patient was started on avapritinib leading to significant decrease in the frequency of her diarrhea and a significant reduction in her tryptase levels. Her course was complicated by arthralgias leading to a decrease in her avapritinib dose and ultimately a degranulation episode requiring hospitalization. Following dose re-escalation, patient has remained clinically stable without any further adverse events.

Conclusion

We report a case of aggressive systemic mastocytosis with a novel KIT mutation on exon 17 treated with avapritinib leading to a sustained response. While avapritinib is known as a potent inhibitor against the D816V mutation, our case suggests that it may also be effective against other rare KIT mutations in systemic mastocytosis offering more potential treatment options in patients with rare mutations.

Plasma cell leukemia (PCL) is a rare aggressive variant of multiple myeloma. PCL is diagnosed when clonal plasma cells constitute more than 20 % of the total circulating leukocytes or when the absolute plasma cell count exceeds 2 × 10⁹ /L. Extramedullary involvement including cavity effusion is frequently seen at the time of diagnosis. However, soft tissue involvement is rarely encountered with only one published case in the English literature. We report a 74-year-old man, who presented with progressive shortness of breath over a few months. Laboratory studies showed leukocytosis (32 × 109 /L) with 26 % peripheral plasmacytoid cells and significantly elevated lactate dehydrogenase (> 2500 U/L). Serum protein electrophoresis detected a monoclonal IgG lambda band. A 7.4 cm left hilar mass, bilateral pleural effusion, and multiple fluorodeoxyglucose (FDG)-avid subcutaneous nodules in the pelvic and gluteal regions were demonstrated on imaging. Gluteal nodule biopsy revealed diffuse infiltrative CD138+ and MUM1+ cells with aberrant CD4, CD30, and BCL2 expression. The Ki-67 proliferation index was 70 %. Bone marrow biopsy showed sheets of atypical plasma cells with lambda-restriction and CD138 and MUM1 expression without cyclin D1 and CD20 expression. These cells comprise approximately 70–80 % of the bone marrow cellularity. A similar immunophenotype was demonstrated in peripheral and bone marrow flow cytometry. Molecular and cytogenetics showed an abnormal clone with a complex karyotype including monosomy 13 and 14q deletion. Overall, these findings are consistent with a plasma cell neoplasm. Our case study illustrates soft tissue involvement in PCL, which is rarely seen.

Introduction

Tie2 is a receptor tyrosine kinase and regulates angiogenesis and vascular quiescence. Given that Tie2 modulates microvascular density in cancer, we hypothesized that deletion of Tie2 in blood cells can inhibit progression of myelodysplastic syndrome (MDS). We attempted to understand the role of Tie2 in development of MDS by using an Ezh2/Tet2 double knock out (DKO) mouse model.

Methods

We transplanted bone marrow (BM) cells isolated from Cre-ERT2 mice, Tie2^flox/wt; Cre-ERT2 mice, Ezh2^flox/flox; Tet2^flox/flox; Cre-ERT2 mice, Ezh2^flox/flox; Tet2^flox/flox; Tie2^flox/wt; Cre-ERT2 mice and Ezh2^flox/flox; Tet2^flox/flox; Tie2^flox/flox; Cre-ERT2 mice into lethally-irradiated Ly5.1⁺ recipient mice. Ezh2, Tet2 and Tie2 genes were deleted by administration of tamoxifen one month post the transplantation.

Results

We found that Ezh2^−/−Tet2^−/- DKO, Ezh2^−/−Tet2^−/- Tie2^+/− (DKOTie2^+/−) and Ezh2^−/−Tet2^−/- Tie2^−/− TKO mice all developed MDS and MDS/MPN, showing anemia and dysplastic cells in the peripheral blood (PB) and the BM; however, DKOTie2^+/− mice showed significantly longer survival than did DKO mice and TKO mice. While DKO mice showed deformed CD31⁺ endothelial cells and increased vascular density in the BM, DKOTie2^+/− mice mitigated the altered vascular formation in the BM. RNA-sequencing revealed that DKOTie2^+/− stem cells repressed expression of genes involved in interferon, cell cycles and angiogenesis, compared to DKO stem cells, suggesting that the haploinsufficiency of Tie2 impaired the property of MDS cells to drive angiogenesis in the BM, resulting in the delayed development of MDS.

Conclusions

We are now working on the molecular mechanism of how the Tie2 gene in blood cells modulates the angiogenesis to drive the progression of MDS.

Introduction

Germline SAMD9 and SAMD9L mutations (SAMD9/9L^mut) cause a novel bone marrow failure and pediatric myelodysplastic syndrome. Despite >400 patients reported, evaluating variants remains challenging with >70% of germline SAMD9/9L^mut classified as variants of uncertain significance, mainly due to heterogenous phenotypes and lack of functional assays. Many patients acquire compensatory clones including secondary SAMD9/9L^mut and UPD7q with loss of the mutant allele, along with maladaptive, stress-induced monosomy 7. Monosomy 7 poses unique surveillance challenges as it may disappear spontaneously over time, precluding the need for HSCT.

Methods

We utilized our prospective somatic surveillance database to identify genetic patterns and evolution in SAMD9/9L^mut patients (median age 8 years). Using high-sensitivity myeloid gene panel and SNP array, we evaluated hematopoietic specimens of 23 patients with SAMD9/9L syndromes. For comparison, we analyzed a cohort of 132 patients with other BMF/MDS conditions. Serial analysis was performed in 39% (61/155) of patients for a median duration of 15.7 (1.4-53.2) months.

Results

We found 33 somatic SAMD9/9L^mut in 61% (14/23), UPD7q in 26% (6/23), and monosomy 7 in 48% (11/23) of patients with germline SAMD9/9L^mut. Somatic SAMD9/9L^mut and UPD7q were not identified in the comparative cohort, resulting in 100% specificity and positive predictive value to rule-in germline SAMD9/9L syndromes. Notably, no patient (including monosomy 7 cases) developed advanced MDS, leukemia, or cancer driver mutations with up to 4.4 years of follow-up.

Conclusions

Somatic SAMD9/9L^mut and UPD7q act as a “natural functional assay” confirming pathogenicity of germline SAMD9/9L^mut. Despite high rates of monosomy 7, leukemic progression is rare in SAMD9/9L syndromes.

Introduction

Fanconi Anemia (FA) gene is a congenital bone marrow failure (BMF) disorder caused by impaired replication stress (RS) associated DNA damage repair. We previously described FA fetal liver (FL) hematopoietic stem cell (HSC) exhibited high mitochondrial oxidative phosphorylation (OXPHOS) and mitophagy when it was under RS. Thrombopoietin (TPO) signaling is known to modulate mitochondria metabolism in HSC. While TPO agonists are utilized for the treatment of BMFs such as aplastic anemia, whether and how these drugs can affect FA and its progression to hematopoietic malignancy is unknown.

Methods

To clarify the TPO signal of response in FA, we analyzed FA mice [an1] treated with TPO agonists or crossed with TPO-deficient mice.

Results

Embryonic mice FA fetal liver HSCs were rescued with TPO agonist administration. TPO deficiency no rescued FA FL HSC phenotype.

Conclusions

TPO signal confers developmental FA HSC deficit. Further investigation is needed to describe the mechanism and efficiency.

Introduction

In addition to direct cytotoxic effect of hypomethylaging agents (HMAs) on myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) cells, HMA upregulates effector T-cell function by demethylating T-cell exhaustion-associated genes (Hazem, Cell 2017) or trafficking effector T-cells to bone marrow (BM) by Th1-type chemokines activation (Peng, Nature 2019). We tried to elucidate dynamic changes of immune cells profile and gene expression after HMA treatment in patients with MDS or AML.

Methods

We performed scRNAseq on consecutive BM samples from an high-risk MDS (HR-MDS) patient treated with azacitidine: we categorized cell clusters based on immune-cell types, assessed changes in immune-cell proportions following treatment, and conducted a differentially expressed genes (DEG) analysis. In addition, changes in immune-cells proportions before vs. after HMA treatment in HR-MDS patients were evaluated, and the association between the immune-cell proportions changes and response to HMA were analyzed from seuqential BM aspirates from HR-MDS/AML patients.

Results

In the scRNAseq data, the NK-cell cluster exhibited the most significant increase in the relative proportion up to response, whereas the effector T-cells clusters showed only a modest increase of proportion upon HMA response. DEG revealed an overexpression of CXCR4 in the NK-cell cluster at the timepoint of response, suggesting the recruitment of NK cells to BM. The trafficking of NK cells to BM after HMA response were reproduced in serial BM aspirates from patients with HR-MDS/AML.

Conclusions

NK-cells recruited into BM through CXCR4 overexpression and anti-leukemic cytotoxicity exerted by NK cells may represent a crucial immunological mechanism of action for HMAs in patients with HR-MDS/AML.

Introduction

We report the full analysis of the COMMANDS trial assessing efficacy and safety of luspatercept versus epoetin alfa (EA) in ESA-naive patients with LR-MDS.

Methods

363 patients (aged ≥18 y, with transfusion-dependent LR-MDS, serum erythropoietin <500 U/L) were randomized 1:1 to luspatercept or EA. Primary endpoint was achievement of red blood cell transfusion independence (RBC-TI) ≥12 wk with concurrent mean hemoglobin increase ≥1.5 g/dL (wk 1–24). Secondary endpoints included achievement of RBC-TI ≥12 and 24 wk, hematologic improvement–erythroid (HI-E) ≥8 wk (wk 1–24), RBC-TI ≥12 wk duration, and safety.

Results

As of 31Mar2023, 110/182 (60.4%) luspatercept-treated versus 63/181 (34.8%) EA-treated patients achieved the primary endpoint (P<0.0001). Primary endpoint achievement favored luspatercept in most subgroups including region. Median (range) treatment duration was 51.3 (3–196) and 37.0 (1–202) wk for luspatercept versus EA. 68.1% and 48.6% of luspatercept- versus EA-treated patients, respectively, achieved RBC-TI ≥12 wk; 47.8% and 30.9% achieved RBC-TI 24 wk; 74.4% and 53.0% achieved HI-E ≥8 wk. Median (95% CI) duration of RBC-TI ≥12 wk was 128.1 wk (108.3–not estimable [NE]) with luspatercept versus 89.7 wk (55.9–157.3) with EA (HR, 0.534; Figure). 2.7% and 3.3% of luspatercept- and EA-treated patients, respectively, progressed to AML; 97.8% and 92.2% reported any-grade treatment-emergent adverse events (TEAEs); 58.5% and 49.2% reported grade 3/4 TEAEs. Death rates on- and post-treatment were similar between arms.

Conclusions

RBC-TI duration and erythroid responses achieved with luspatercept were superior to EA. Luspatercept safety results were consistent with previous MDS studies.

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy associated with various combinations of gene mutations, epigenetic abnormalities, and chromosome rearrangement-related gene fusions. Despite the significant degree of heterogeneity in its pathogenesis, many gene fusions and point mutations are recurrent in AML and have been employed in risk stratification over the last several decades. Gene fusions have long been recognized for understanding tumorigenesis and their proven roles in clinical diagnosis and targeted therapies. Advances in DNA sequencing technologies and computational biology have contributed significantly to the detection of known fusion genes as well as for the discovery of novel ones. Several recurring gene fusions in AML have been linked to prognosis, treatment response, and disease progression. In this report, we present a case with a long history of essential thrombocythemia and hallmark CALR mutation transforming to AML characterized by a previously unreported AKAP9::PDGFRA fusion gene. We propose mechanisms by which this fusion may contribute to the pathogenesis of AML and its potential as a molecular target for tyrosine kinase inhibitors.