Prognostic stratification of molecularly and clinically distinct subgroup in children with acute monocytic leukemia

Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients With Acute Myeloid Leukemia Harboring KMT2A Rearrangement and Its Prognostic Factors

KMT2A rearrangement (KMT2A-r) in patients with acute myeloid leukemia (AML) is associated with poor outcomes; the prognostic factors after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain unclear. We investigated 364 adults with AML who underwent allo-HSCT between April 2016 and May 2022, and 45 had KMT2A-r among them. Propensity score analysis with 1:1 matching and the nearest neighbor matching method identified 42 patients in KMT2A-r and non-KMT2A-r cohorts, respectively. The 2-year overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), and non-relapsed mortality rates of patients with KMT2A-r (n = 45) were 59.1%, 49.6%, 41.5%, and 8.9%, respectively. Using propensity score matching, the 2-year OS rate of patients with KMT2A-r (n = 42) was lower than that of those without KMT2A-r (n = 42; 56.1% vs 88.1%, P = 0.003). Among patients with KMT2A-r (n = 45), the prognostic advantage was exhibited from transplantation in first complete remission (CR1) and measurable residual disease (MRD) negative, which was reflected in OS, RFS, and CIR (P < 0.001, P < 0.001, and P = 0.002, respectively). Furthermore, patients with AF6 had poorer outcomes than those with AF9, ELL, and other KMT2A-r subtypes (P = 0.032, P = 0.001, and P = 0.001 for OS, RFS, and CIR, respectively). However, no differences were found in the OS, RFS, and CIR between patients with KMT2A-r with and without mutations (all P > 0.05). Univariate and multivariate analyses revealed that achieving CR1 MRD negative before HSCT was a protective factor for OS [hazard ratio (HR) = 0.242, P = 0.007], RFS (HR = 0.350, P = 0.036), and CIR (HR = 0.271, P = 0.021), while AF6 was a risk factor for RFS (HR = 2.985, P = 0.028) and CIR (HR = 4.675, P = 0.004). The prognosis of patients with KMT2A-r AML was poor, particularly those harboring AF6-related translocation; however, it is not associated with the presence of mutations. These patients can benefit from achieving CR1 MRD negative before HSCT.

Pediatric acute myeloid leukemia and hyperleukocytosis with WBC count greater than 50 × 109/L

BACKGROUND

Acute myeloid leukemia (AML) and hyperleukocytosis have an unfavorable prognosis, but the impact of hyperleukocytosis on the prognosis of pediatric AML remains uncertain. We investigated the clinical characteristics and prognosis of pediatric AML with hyperleukocytosis, defined as WBC ≥ 50 × 109/L.

METHODS

A total of 132 patients with newly diagnosed childhood AML with hyperleukocytosis were consecutively enrolled at our center from September 2009 to August 2021 to investigate prognostic factors and clinical outcomes.

RESULTS

Hyperleukocytosis occurred in 27.4% of AML patients. Pediatric patients with hyperleukocytosis had similar CR and OS rates to those without hyperleukocytosis, but had a lower EFS rate. In our study, rates of CR1, mortality, relapsed/refractory disease, and HSCT were comparable between AML patients with WBC counts of 50-100 × 109/L and ≥ 100 × 109/L. AML patients with a WBC count of 50-100 × 109/L had a similar 5-year OS rate to patients with a WBC count ≥ 100 × 109/L (74.6% vs. 75.4%, P = 0.921). Among all patients with hyperleukocytosis, the FAB M5 subtype was associated with significantly inferior survival, and the prognosis of CBF-AML was good.

CONCLUSIONS

Pediatric AML patients with hyperleukocytosis have the similar prognosis regardless of whether their WBC count is 50-100 × 109/L or ≥ 100 × 109/L.

Establishing a novel Fanconi anemia signaling pathway-associated prognostic model and tumor clustering for pediatric acute myeloid leukemia patients

Considering the connection between the Fanconi anemia (FA) signaling pathway and tumor development, we aim to investigate the links between the FA gene expression and the survival prognosis of acute myeloid leukemia (AML) patients. Our study begins by identifying two distinct clusters of pediatric AML patients. Following the batch matching of the TARGET-AML, TCGA-LAML GSE71014, GSE12417, and GSE37642 cohorts, the samples were divided into a training set and an internal validation set. A Lasso regression modeling analysis was performed to identify five signatures: BRIP1, FANCC, FANCL, MAD2L2, and RFWD3. The AML samples were stratified into high- and low-risk groups by evaluating the risk scores. The AML high-risk patients showed a poorer overall survival prognosis. To predict the survival rates, we developed an FA Nomogram incorporating risk score, gender, age, and French-American-British classification. We further utilized the BEAT-AML cohort for the external validation of FA-associated prognostic models and observed good clinical validity. Additionally, we found a correlation between DNA repair, cell cycle, and peroxide-related metabolic events and FA-related high/low risk or cluster 1/2. In summary, our novel FA-associated prognostic models promise to enhance the prediction of pediatric AML prognosis.

Estimating the prevalence of pediatric hematological malignancies in Al-Madinah Al-Munawwarah, Saudi Arabia

OBJECTIVES

To provide an updated estimate to the prevalence of pediatric hematological malignancies (HMs) in the Al-Madinah Al-Munawwara, Saudi Arabia.

METHODS

This is a retrospective study that was carried out between 2016 and 2022. The study population was comprised of 171 children under 16 who had been diagnosed with HMs. The data was compiled from King Salman Medical City's Maternity and Children's Hospital, Al-Madinah Al-Munawwarah, Saudi Arabia.

RESULTS

Among the 171 HM patients (64% males and 36% females), 13 subtypes were identified, with B-cell acute lymphoblastic leukemia having the highest incidence (70.3%). Acute myelomonocytic leukemia (8.7%), T-cell acute lymphoblastic leukemia (4.7%), and acute promyelocytic leukemia (3.5%) were the next most common types of HMs. Other rare cases were also found.

CONCLUSION

Prevalence rate can be utilized to monitor the progression of disease incidence. Here, HMs demonstrated a pattern of increasing incidence in males over a 7-year period, with a higher rate in early childhood. There were 13 types of HMs diagnosed, with B-acute lymphocytic leukemia having the highest incidence. Although juvenile cancer is rare, it is nonetheless a significant cause of mortality in children. A successful prognosis requires prompt and accurate diagnosis and treatment.

Pediatric non–Down’s syndrome acute megakaryoblastic leukemia patients in China: A single center's real-world analysis

Non-Down’s syndrome acute megakaryocytic leukemia (non-DS-AMKL) is a subtype of childhood acute myeloid leukemia (AML), whose prognosis, prognostic factors and treatment recommendations have not yet to be defined in children. We conducted a retrospective study with 65 newly diagnosed non-DS-AMKL children from August 2003 to June 2020 to investigate the clinical impact of factors and clinical outcome. Among all 65 patients, 47 of them were treated at our center who received three different regimens due to time point of admission (CAMS-another, CAMS-2009 and CAMS-2016 protocol), and the efficacy were compared. Patients with newly diagnosed non-DS-AMKL accounted for 7.4% of pediatric AML cases. The median age of the patients was 18 months at diagnosis, and over 90% of them were under three-years-old. The overall survival (OS) rates were 33.3% ± 1.7%, 66.7% ± 24.4% and 74.2% ± 4.0% for three groups (CAMS-another, CAMS-2009 and CAMS-2016 regimen), respectively. In CAMS-2016 group, the complete remission (CR) rate after induction was 67.7% (21/31), while the total CR rate after all phases of chemotherapy was 80.6% (25/31). The 2-year survival probability did not significantly improve in patients underwent HSCT when compared with non-HSCT group (75.0% ± 4.7% vs. 73.9% ± 4.6%, p=0.680). Those who had a “dry tap” during BM aspiration at admission had significantly worse OS than those without “dry tap” (33.3% ± 8.6% vs. 84.0% ± 3.6%, p=0.006). Moreover, the results also revealed that patients with CD34+ had significantly lower OS (50.0% ± 6.7% vs. 89.5% ± 3.5%, p=0.021), whereas patients with CD36+ had significantly higher OS than those who were negative (85.0% ± 4.0% vs. 54.5% ± 6.6%, p=0.048). In conclusion, intensive chemotherapy resulted in improved prognosis of non-DS-AMKL children and subclassification may base on “dry tap” and immunophenotypic. Although some progress has been made, outcomes of non-DS-AMKL children remain unsatisfactory, especially in HSCT group, when compared with other AML types.

Discovery of Novel, Potent, and Selective Small-Molecule Menin-Mixed Lineage Leukemia Interaction Inhibitors through Attempting Introduction of Hydrophilic Groups

Introduction of the N,N-dimethylaminoethoxy group to pyrido[3,2-d]pyrimidine led to the discovery of menin-mixed lineage leukemia (MLL) interaction inhibitor C20. C20 showed strong binding affinity to menin protein and achieved sub-micromolar potency in cell growth inhibition. C20 had good selectivity for the inhibition of the interaction between menin and MLL in the kinase profile evaluation. Pharmacokinetic studies demonstrated that C20 possessed good stability and low clearance rate in liver microsomes and acceptable bioavailability in rats. Subsequent oral administration of C20 showed potent antitumor activity in the MV4;11 subcutaneous xenograft models of MLL-rearranged leukemia. The docking study showed that C20 bound highly with menin, and the N,N-dimethylaminoethoxy group occupied the F9 pocket of menin. This study proved that introducing a hydrophilic group into the F9 pocket of menin would be a new strategy for the design of menin-MLL interaction inhibitors with potent binding affinity and improved physical properties.

Development and validation of a prognostic scoring model to risk stratify childhood acute myeloid leukaemia

To create a personal prognostic model and modify the risk stratification of paediatric acute myeloid leukaemia, we downloaded the clinical data of 597 patients from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database as a training set and included 189 patients from our centre as a validation set. In the training set, age at diagnosis, -7/del(7q) or -5/del(5q), core binding factor fusion genes, FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)/nucleophosmin 1 (NPM1) status, Wilms tumour 1 (WT1) mutation, biallelic CCAAT enhancer binding protein alpha (CEBPA) mutation were strongly correlated with overall survival and included to construct the model. The prognostic model demonstrated excellent discriminative ability with the Harrell's concordance index of 0.68, 3- and 5-year area under the receiver operating characteristic curve of 0.71 and 0.72 respectively. The model was validated in the validation set and outperformed existing prognostic systems. Additionally, patients were stratified into three risk groups (low, intermediate and high risk) with significantly distinct prognosis, and the model successfully identified candidates for haematopoietic stem cell transplantation. The newly developed prognostic model showed robust ability and utility in survival prediction and risk stratification, which could be helpful in modifying treatment selection in clinical routine.

[Effect of polydatin on the proliferation and apoptosis of THP-1 cells and the mechanism]

OBJECTIVES

To explore the effect of polydatin on the proliferation and apoptosis of acute monocytic leukemia cell line THP-1 and the possible mechanism.

METHODS

After THP-1 cells were treated with polydatin at gradient concentrations for 24 hours and 48 hours, their proliferation was determined by CCK-8 assay, and half maximal inhibitory concentration (IC50) was calculated. Logarithmically growing THP-1 cells were divided into two groups, a polydatin treatment group (treated with IC50 of polydatin) and a blank control group (treated without polydatin solution), and incubated for 48 hours. Cell apoptosis and cell cycle were measured by flow cytometry. The expression levels of PI3K, AKT, p-AKT, mTOR, p-mTOR, p70 S6K, and p-p70 S6K proteins were measured by Western blotting.

RESULTS

After treatment with polydatin, the proliferation of THP-1 cells was strongly inhibited, and the IC50 at 48 hours was 1 800 μmol/L. After treatment with 1 800 μmol/L polydatin solution for 48 hours, the apoptosis rate of THP-1 cells increased significantly compared with the blank control group (P<0.05). The cell cycle was arrested in the G0/G1 and S phases, with a significantly increased proportion of cells in the G0/G1 phase and a significantly decreased proportion of cells in the S phase, as compared with the blank control group (P<0.05). The expression levels of PI3K, AKT, p-AKT, mTOR, p-mTOR, p70 S6K, and p-p70 S6K proteins decreased significantly compared with the blank control group (P<0.05).

CONCLUSIONS

Polydatin can effectively inhibit the proliferation, block the cell cycle, and induce the apoptosis of THP-1 cells, which may be related to inhibition of the PI3K/AKT/mTOR signaling pathway.

Comprehensive immunophenotypic study of acute myeloid leukemia with KMT2A (MLL) rearrangement in adults: A single-institution experience

BACKGROUND

Acute myeloid leukemia (AML) with KMT2A (MLL) rearrangement is known for monocytic or myelomonocytic differentiation, but the full immunophenotypic spectrum and dynamic changes of the immunophenotype in this genetically defined disease have not been systematically studied.

METHODS

We reviewed the immunophenotype, karyotype, and mutations at the time of initial diagnosis and relapse of adults with AML with KMT2A rearrangement in our institution between 2007 and 2020.

RESULTS

We identified 102 patients: 44 men and 58 women with a median age of 52 years (range, 18-87). Forty-three patients were considered to be therapy-related. Twenty-four out of 64 patients relapsed from complete remission after induction therapy, 34 had persistent/progressive disease, and 58 patients died with a median overall survival of 17 months. We detected five immunophenotypes: immature monocytic (38%); myelomonocytic (22%); myeloblastic (22%); mature monocytic (10%); and acute promyelocytic (APL)-like (8%). By chromosomal breakpoints, we presumed 11 different partners; t(9;11) (p22;q23)/MLLT3-KMT2A was the most common rearrangement (n = 56, 55%), followed by t(6;11) (q27;q23)/AFDN-KMT2A (n = 13,13%). Patients with t(6;11) (q27;q23)/AFDN-KMT2A preferentially showed a myeloblastic phenotype (p = 0.026). Mutations were detected in 39/64 (61%) cases, and RAS pathway (NRAS/KRAS/PTPN11) was involved in 26/64 (41%) cases. None of the APL-like cases had mutations detected. At the time of disease relapse, 10/24 (42%) showed major immunophenotypic change, and 7/10 cases gained additional cytogenetic and/or molecular alterations.

CONCLUSION

The immunophenotype of AML with KMT2A rearrangement is more diverse than previously recognized, with a substantial subset showing no evidence of monocytic differentiation. Major immunophenotype change is common at the time of relapse.

Diagnostic challenges in acute monoblastic/monocytic leukemia in children

Acute monoblastic/monocytic leukemia (AMoL), previously defined as M5 according to FAB classification, is one of the most common subtypes of Acute Myeloid Leukemia (AML) in children, representing ~15-24% of all pediatric AMLs. Currently, the characterization of monocytic-lineage neoplasia at diagnosis includes cytomorphology, cytochemistry, immunophenotyping by multiparametric flow cytometry, cytogenetics, and molecular biology. Moreover, measurable residual disease (MRD) detection is critical in recognizing residual blasts refractory to chemotherapy. Nonetheless, diagnosis and MRD detection may still be challenging in pediatric AMoL since the morphological and immunophenotypic features of leukemic cells potentially overlap with those of normal mature monocytic compartment, as well as differential diagnosis can be troublesome, particularly with Juvenile Myelomonocytic Leukemia and reactive monocytosis in infants and young children. A failure or delay in diagnosis and inaccuracy in MRD assessment may worsen the AMoL prognosis. Therefore, improving diagnosis and monitoring techniques is mandatory to stratify and tailor therapies to the risk profile. This Mini Review aims to provide an updated revision of the scientific evidence on pediatric AMoL diagnostic tools.

Targeting EZH2-mediated methylation of histone 3 inhibits proliferation of pediatric acute monocytic leukemia cells in vitro

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and a catalytic subunit of the polycomb repressive complex 2 (PRC2) that catalyzes the mono-, di-, and tri-methylation of histone H3 at Lys 27 (H3K27me3) to facilitate chromatin-remodeling and gene-silencing functions. Previous reports showed a significant association of EZH2 aberrations in pediatric cancers, such as soft tissue sarcomas and glioblastoma. Recent reports in human subjects and animal models have also suggested a central role of EZH2 in the induction and progression of acute myeloid leukemia. In this study, we aimed to investigate the molecular status of EZH in cell lines derived from distinct pediatric leukemia to assess the efficacy of targeting EZH2 to suppress cancer cell survival and proliferation. Our results showed that EZH2 protein is overexpressed in the pediatric monocytic cell-line THP-1, but not in other leukemia-derived cell lines MV4;11 and SEM. Screening a panel of methyltransferase inhibitors revealed that three inhibitors; GSK126, UNC1999 and EPZ-5687 are the most potent inhibitors that suppressed EZH2 activity selectively on lysine 27 which resulted in increased apoptosis and inhibition of AKT and ERK protein phosphorylation in THP-1 cells. Our data demonstrated a significant increase in apoptosis in cells treated with drug combination (EZH2i and selinexor) compared to EZH2i inhibitors alone. Taken together, our data provide initial evidence that targeting EZH2 is a promising therapeutic strategy for the treatment of subtypes of pediatric AML. Also, combining EZH2 inhibitors with selinexor may increase the treatment efficacy in these patients.

Pulmonary Manifestations of Hematologic and Oncologic Diseases in Children

Pulmonary complications are common in children with hematologic or oncologic diseases, and many experience long-term effects even after the primary disease has been cured. This article reviews pulmonary complications in children with cancer, after hematopoietic stem cell transplant, and caused by sickle cell disease and discusses their management.

Improved outcome of children with relapsed/refractory acute myeloid leukemia by addition of cladribine to re-induction chemotherapy

Background

The preferred salvage treatment for children with relapsed/refractory acute myeloid leukemia (R/R‐AML) remains unclear. The combination of cladribine/Ara‐C/granulocyte‐colony stimulating factor and mitoxantrone (CLAG‐M) shown promising results in adult R/R‐AML. We aim to investigate the efficacy and safety of CLAG‐M versus mitoxantrone/etoposide/cytarabine (MEC) or idarubicin/etoposide/cytarabine (IEC) in R/R‐AML children.

Methods

Fifty‐five R/R‐AML children were analyzed. The overall response rate (ORR), overall survival (OS), and progression‐free survival (PFS) at 3‐year were documented. Karyotype or mutations status were summarized as different risk groups.

Results

The ORR was achieved in 80% (16/20) and 51% (18/35) of patients after one‐cycle of CLAG‐M and MEC/IEC treatment (p < 0.001). The CLAG‐M group's OS (66.8% ± 16.2% vs. 40.4% ± 10.9%, p = 0.019) and PFS (52.6% ± 13.7% vs. 34.9% ± 9.1%, p = 0.036) at 3‐year was significantly higher than the MEC/IEC group. In high‐risk patients, 33.3% experienced progression of disease (PD) and 22.2% dead in CLAG‐M group, while 50% experienced PD and 43.8% dead in MEC/IEC. When it comes to low‐risk group, none of them in CLAG‐M experienced PD or death, while up to 50% of patients received MEC/IEC suffered PD, and all of them died eventually. Similar results were also found in the intermediate‐risk group. Surprisingly, the presence of FLT3‐ITD was associated with poor outcome in both groups. The most common adverse events were hematologic toxicities, and the incidence was similar in both group.

Conclusions

CLAG‐M group demonstrated effective palliation along with acceptable toxicity in R/R‐AML patients. However, patients with FLT3‐ITD may benefit less from CLAG‐M, owing to higher PD rate and all‐cause mortality than other patients.

Prognostic stratification of molecularly and clinically distinct subgroup in children with acute monocytic leukemia

Background

The prognosis of children with acute monocytic leukemia (AML‐M5) remains unsatisfactory and the risk profile is still controversial. We aim to investigate the prognostic value of clinical and cytogenetic features and propose a new risk stratification in AML‐M5 children.

Methods

We included 132 children with AML‐M5. Overall survival (OS) and progression‐free survival (PFS) were documented. Cox regression was performed to evaluate the potential risk factors of prognosis.

Results

The 5‐year‐OS was 46.0% (95% confidence intervals, 41.6%‐50.4%) in all patients. There was significantly lower OS in the age ≤ 3 years old (P = .009) and hyperleukocytosis (P < .001). The FMS‐like tyrosine kinase 3 (FLT3)‐internal tandem duplication (ITD) and MLL‐rearrangement carriers were associated with fewer survivors in all patients (37.1% and 36.7%) and chemotherapy‐only group (19.0% and 35.0%). Notably, the number of survivor with MLL‐rearrangement did not increase in hematopoietic stem cell transplant (HSCT) group. According to the Cox regression analysis, HSCT was a significantly favorable factor (P = .001), while hyperleukocytosis, age ≤ 3 years old, and BM blast ≥ 70% adversely affected the OS in all patients (all P < .05). Additionally, FLT3‐ITD was a risk factor for OS in the chemotherapy‐only group (P = .023), while hyperleukocytosis and age ≤ 3 years independently contributed to poor PFS (both P < .05). In comparison to the standard‐risk group, significant poorer outcome was found in the high‐risk group (both P < .005).

Conclusions

We propose that AML‐M5 children with any of MLL‐rearrangement, FLT3‐ITD, hyperleukocytosis, BM blast ≥ 70%, or age ≤ 3 years old are classified into the high‐risk group, and HSCT is beneficial especially in patients with FLT3‐ITD mutation, hyperleukocytosis, and age ≤ 3 years old. Importantly, the choice of HSCT should be made more carefully in children with MLL‐rearrangement for its suboptimal performance.