Leukemia Research Reports最新文献

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.

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.

Introduction

MicroRNAs (miRNAs),are significant regulators of human hematopoietic stem cells. Their deregulation contributes to hematological malignancies.The let-7 family has been found frequently deregulated in malignancies.In MDS various alterations of miRNAs have been reported.High Mobility Group AT-Hook 2 (HMGA2) protein functions as a transcriptional regulator. In this study, we investigated the HMGA2 expression in MDS and specifically in patients with fibrosis we studied the prognostic significance of four members of the let-7 family (let-7a, let-7b, let-7c, let-7d).

Methods

RNA extraction, reverse transcription, anda SYBR Green based real-time PCR were performed for the absolute quantification of HMGA2, using standard protocols. After RNA polyadenylation and reverse transcription with an oligo-dT adapter primer, miRNAs transcript levels were determined using the SYBR Green chemistry. IBM SPSS statistics, version 26 (IBM Corporation, North Castle, NY, USA) was used for the analysis.

Results

HMGA2 gene expression was investigated in 78 patients with MDS, whereas transcript levels of four members of the let-7 family (let-7a, let-7b, let-7c, let-7d) were analyzed in 11 patients with fibrosis. Let-7a transcript levels were significantly higher in MDS patients who developed acute myeloid leukemia (AML) compared to the group that did not (p=0.0141). Let-7d presented a negative correlation (p=0.0408). A moderate (p =0.0483) negative correlation of HMGA2 with let-7c, and a strong positive correlation (p =0.0481) with let-7d, were observed.

Conclusions

In literature, the let-7/HMGA2 linkage could be a signature in MDS pathogenesis. Let-7a level was found higher in transformation to AML,defining it as a poor prognostic factor, in contrast with the protective role of high let-7d.

Introduction

Allogeneic stem cell transplant (alloSCT) remains the only curative treatment for the myelodysplastic syndromes (MDS), but relapse is common. Studies using error-corrected sequencing (ECS) on bulk bone marrow (BM) have shown that molecular residual disease is predictive of relapse. But the sensitivity of this approach is limited, and it is not known what cells give rise to relapse.

Methods

To test our hypothesis that hematopoietic stem cells (HSCs) drive post-transplant relapse, we developed a protocol to perform ECS on as few as <25 HSCs. We used this new tool to ask if post-transplant relapse originates from MDS HSCs, and whether their persistence predicts for relapse. We also sought to determine if curing MDS requires eradication of MDS HSCs, or whether they are simply suppressed by graft-versus-tumor effect.

Results

We sequenced HSCs, multipotent progenitors (MPPs), restricted progenitors, and bulk BM from 33 MDS patients who underwent alloSCT (with an additional 20 specimens to be presented). Persistence of mutations in HSCs/MPPs in the first 120 days post-transplant was 100% specific and 84% sensitive for relapse, while detection of mutations in bulk BM was only 41% sensitive and 85% specific (Figure). Average time from mutation detection in HSCs/MPPs to relapse was 6.9 months.

Conclusions

In conclusion, we have shown for the first time that relapse of MDS after allogeneic transplant is driven by failure to eradicate MDS HSCs, and that detection of MDS HSCs early after transplant is highly predictive for relapse. This can identify patients who may benefit from early post-transplant interventions to forestall relapse.

Mixed-phenotype acute leukemia (MPAL) is a rare form of leukemia with ambiguous lineage, and there are challenges in accurately diagnosing this entity according to formal criteria. Here we report a case which was initially diagnosed as “AML” based on atypical peripheral blood flow cytometry that was subsequently determined to be B-ALL with KMT2A rearrangement based on marrow results. Although KMT2A rearrangements represent a defining genetic abnormality for acute leukemia of ambiguous lineage, this case did not meet the criteria for MPAL based on WHO 2022 criteria. This case highlights the diagnostic challenges of MPAL and the potential limitations of the current classification. We discuss the most appropriate workup and management of these patients and identify areas for future study.

We report results of a 65-year-old patient with lower-risk myelodysplastic syndrome and multilineage dysplasia treated with hypomethylating agents. After failure of erythropoietin and thalidomide, the patient received azacitidine and achieved hematological remission for 95 months. In 2016, the treatment was switched to decitabine with promising results. These data showed that azacitidine used as a third-line treatment resulted in an exceptionally long-lasting positive hematological response after standard first- and second-line therapies had failed. Additionally, the patient experienced a good quality of life with no complications related to profound cytopenia, and continues to do so at the time of this report's preparation.