RUNX1 mutation associated with clonal evolution in relapsed pediatric acute myeloid leukemia with t(16;21)(p11;q22)

TLS/FUS-ERG fusion gene in acute leukemia and myelodysplastic syndrome evolved to acute leukemia: report of six cases and a literature review

To investigate the pathogenesis and the refractory/relapse mechanisms in patients with t(16;21)(p11;q22), we retrospectively analyzed the clinical data of six cases in our hospital and sixty-two cases reported in the literature. Among the patients in our hospital, five cases were diagnosed as acute leukemia, and one was myelodysplastic syndrome evolved to acute myeloid leukemia, harboring TLS/FUS-ERG fusion gene; all the cases were detected t(16;21)(p11;q22) translocation, and five cases showed additional chromosomal abnormalities. We firstly report a novel three-way translocation t(11;16;21)(q13;p11;q22), which may affect the prognosis of leukemia with TLS-ERG fusion gene because this patient shows a more satisfactory treatment effect and deeper remission. And we found patients with TLS-ERG are more likely to have bone and arthrosis pain. Besides, CD56 and CD123 were positive in these cases, which are related to poor prognosis and the character of refractory. Moreover, some gene mutations are involved, and GATA2 and SMAD4 mutations were identified when the disease progressed from myelodysplastic syndrome to leukemia. Among sixty-two patients reported in the literature, valid positive percent of CD56 and CD123 were 81% and 14.3%, respectively. Mutation of the RUNX1 gene was detected in four cases, and one patient had multiple mutations, including BCOR, PLCG1, DIS3, BRAF, JAK2, and JAK3. The prominent feature of leukemia carrying the TLS/FUS-ERG gene is its poor prognosis. The relevant mechanism includes new mutation, jumping translocation, different transcripts, and so on. The mechanism still acquaints scarcely, which requires further study.

The transformation of isolated gastric myeloid sarcoma into acute myeloid leukemia presenting with a complex karyotype and TLS-ERG gene fusion: A case report

RATIONALE

Isolated myeloid sarcoma (MS) is characterized by the rapid proliferation of myeloblasts of acute myeloid leukemia (AML), without any blood or bone marrow involvement. This disease can manifest with extramedullary organ involvement, such as the skin, lymph nodes, bone, brain, breast cervix, and visceral organs, while the occurrence of myeloid sarcomas in the stomach is rare. Isolated MS has been associated with acute myeloid leukemia (AML), but the rapid progression of MS to acute myeloid leukemia with a complex karyotype and TLS-ERG fusion gene is even rarer.

PATIENT CONCERNS

A 33-year-old woman suffered from persistent epigastric pain accompanied by two months of anorexia and nausea, as well as 1-week of melena.

DIAGNOSIS

This patient was initially diagnosed with gastric MS that eventually transformed into AML with a complex karyotype and TLS-ERG fusion gene, 4 months later.

INTERVENTIONS

Only palliative care, including nutrition support, antacids, blood transfusion, anti-infection methods were used on this patient to determine the cachexia status and the family's requirement.

OUTCOMES

Routine follow-up results demonstrated this patient had died due to cerebral hemorrhage five months after the diagnosis of MS.

LESSONS

Comprehensive integration of patient history, imaging features, mass and bone marrow biopsy, and molecular cytogenetic may provide insights that could help us avoid the misdiagnosis of gastric MS. Isolated gastric MS can rapidly progress to AML with a poor prognosis if the patient does not receive appropriate treatment.

Uncommon cytogenetic abnormalities identifying high-risk acute myeloid leukemia in children

Pediatric acute myeloid leukemia (AML) represents an aggressive disease and is the leading cause of childhood leukemic mortality. The genomic landscape of pediatric AML has been recently mapped and redefined thanks to large-scale sequencing efforts. Today, understanding how to incorporate the growing list of genetic lesions into a risk stratification algorithm for pediatric AML is increasingly challenging given the uncertainty regarding the prognostic impact of rare lesions. Here we review some uncommon cytogenetic lesions to be considered for inclusion in the high-risk groups of the next pediatric AML treatment protocols. We describe their main clinical characteristics, biological background and outcome. We also provide some suggestions for the management of these rare but challenging patients and some novel targeted therapeutic options.

Prognostic impact of t(16;21)(p11;q22) and t(16;21)(q24;q22) in pediatric AML: a retrospective study by the I-BFM Study Group

To study the prognostic relevance of rare genetic aberrations in acute myeloid leukemia (AML), such as t(16;21), international collaboration is required. Two different types of t(16;21) translocations can be distinguished: t(16;21)(p11;q22), resulting in the FUS-ERG fusion gene; and t(16;21)(q24;q22), resulting in RUNX1-core binding factor (CBFA2T3). We collected data on clinical and biological characteristics of 54 pediatric AML cases with t(16;21) rearrangements from 14 international collaborative study groups participating in the international Berlin-Frankfurt-Münster (I-BFM) AML study group. The AML-BFM cohort diagnosed between 1997 and 2013 was used as a reference cohort. RUNX1-CBFA2T3 (n = 23) had significantly lower median white blood cell count (12.5 × 10⁹/L, P = .03) compared with the reference cohort. FUS-ERG rearranged AML (n = 31) had no predominant French-American-British (FAB) type, whereas 76% of RUNX1-CBFA2T3 had an M1/M2 FAB type (M1, M2), significantly different from the reference cohort (P = .004). Four-year event-free survival (EFS) of patients with FUS-ERG was 7% (standard error [SE] = 5%), significantly lower compared with the reference cohort (51%, SE = 1%, P < .001). Four-year EFS of RUNX1-CBFA2T3 was 77% (SE = 8%, P = .06), significantly higher compared with the reference cohort. Cumulative incidence of relapse was 74% (SE = 8%) in FUS-ERG, 0% (SE = 0%) in RUNX1-CBFA2T3, compared with 32% (SE = 1%) in the reference cohort (P < .001). Multivariate analysis identified both FUS-ERG and RUNX1-CBFA2T3 as independent risk factors with hazard ratios of 1.9 (P < .0001) and 0.3 (P = .025), respectively. These results describe 2 clinically relevant distinct subtypes of pediatric AML. Similarly to other core-binding factor AMLs, patients with RUNX1-CBFA2T3 rearranged AML may benefit from stratification in the standard risk treatment, whereas patients with FUS-ERG rearranged AML should be considered high-risk.

Molecular characteristic of acute leukemias with t(16;21)/FUS-ERG

T(16;21)(p11;q22)/FUS-ERG is a rare but recurrent translocation in acute leukemias and in some types of solid tumors. Due to multiple types of FUS-ERG transcripts, PCR-based minimal residual disease detection is impeded. In this study, we evaluated a cohort of pediatric patients with t(16;21)(p11;q22)/FUS-ERG and revealed fusion gene breakpoints. We implemented next-generation sequencing (NGS) on long PCR amplicons for the detection of fusion genes with unknown partners or DNA breakpoints. That allowed us to describe different fusion variants of FUS/ERG in different patients and to detect MRD on both RNA and DNA levels. We also found several accompanying mutations in epigenetic regulators (DNMT3A, ASXL1, BCOR) by targeted NGS approach in AML cases. These mutations preceded full transformation by t(16;21)(p11;q22)/FUS-ERG and allowed us to trace clonal evolution on all steps of therapy. As a casual observation, the ASXL1 mutation was found in the unrelated donor hematopoietic cells.

Gene Mutations as Emerging Biomarkers and Therapeutic Targets for Relapsed Acute Myeloid Leukemia

It is believed that there are key differences in the genomic profile between adult and childhood acute myeloid leukemia (AML). Relapse is the significant contributor of mortality in patients with AML and remains as the leading cause of cancer death among children, posing great challenges in the treatment of AML. The knowledge about the genomic lesions in childhood AML is still premature as most genomic events defined in children were derived from adult cohorts. However, the emerging technologies of next generation sequencing have narrowed the gap of knowledge in the biology of AML by the detection of gene mutations for each sub-type which have led to the improvement in terms of prognostication as well as the use of targeted therapies. In this review, we describe the recent understanding of the genomic landscape including the prevalence of mutation, prognostic impact, and targeted therapies that will provide an insight into the pathogenesis of AML relapse in both adult and childhood cases.

Acute Myeloid Leukemia: Advancements in Diagnosis and Treatment

OBJECTIVE

Leukemia is the most common pediatric malignancy and a major cause of morbidity and mortality in children. Among all subtypes, a lack of consensus exists regarding the diagnosis and treatment of acute myeloid leukemia (AML). Patient survival rates have remained modest for the past three decades in AML. Recently, targeted therapy has emerged as a promising treatment.

DATA SOURCES

We searched the PubMed database for recently published research papers on diagnostic development, target therapy, and other novel therapies of AML. Clinical trial information was obtained from ClinicalTrials.gov. For the major purpose of this review that is to outline the latest therapeutic development of AML, we only listed the ongoing clinical trials for reference. However, the published results of complete clinical trials were also mentioned.

STUDY SELECTION

This article reviewed the latest developments related to the diagnosis and treatment of AML. In the first portion, we provided some novel insights on the molecular basis of AML, as well as provided an update on the classification of AML. In the second portion, we summarized the results of research on potential molecular therapeutic agents including monoclonal antibodies, tyrosine kinase/Fms-like tyrosine kinase 3 (FLT3) inhibitors, epigenetic/demethylating agents, and cellular therapeutic agents. We will also highlight ongoing research and clinical trials in pediatric AML.

RESULTS

We described clonal evolution and how it changes our view on leukemogenesis, treatment responses, and disease relapse. Pediatric-specific genomic mapping was discussed with a novel diagnostic method highlighted. In the later portion of this review, we summarized the researches on potential molecular therapeutic agents including monoclonal antibodies, tyrosine kinase/FLT3 inhibitors, epigenetic/demethylating agents, and cellular therapeutic agents.

CONCLUSION

Gene sequencing techniques should set the basis for next-generation diagnostic methods of AML, and target therapy should be the focus of future clinical research in the exploration of therapeutic possibilities.

Clinical characteristics and laboratory analyses of acute myeloid leukemia with t(16;21)(p11;q22)

The present study reviewed three patients with acute myeloid leukemia (AML) who had the specific genetic abnormality t(16;21)(p11;q22). To investigate the clinical and laboratory characteristics of AML with t(16;21)(p11;q22) translocation, the similarities and differences of clinical characteristics and laboratory examinations were compared, and a literature review was conducted. According to the French-American-British classification system, patient 1 was M4, patient 2 was M1 and patient 3 was M2. The cytogenetic aberrations were 46, XY, t(16;21)(p11;q22)/47, idem, +21 for patient 1 and 46, XX, t(16;21)(p11;q22) for patients 2 and 3. Cytophagocytosis and cluster of differentiation 56 antigen expression were found in all three cases. The prognosis was poor in all the cases. AML with t(16;21)(p11;q22) is a specific subtype of AML that exhibits unique characteristics of morphology, immunology, cytogenetics and clinical features, as well as a poor prognosis. Stem cell transplantation may be the first and only choice for treatment.