TP53 mutations and relevance of expression of TP53 pathway genes in paediatric acute myeloid leukaemia

Pediatric acute myeloid leukemia: Insight into genetic landscape and novel targeted approaches

Acute myeloid leukemia (AML) is a very heterogeneous hematological malignancy that accounts for approximately 20% of all pediatric leukemia cases. The outcome of pediatric AML has improved over the last decades, with overall survival rates reaching up to 70%. Still, AML is among the leading types of pediatric cancers by its high mortality rate. Modulation of standard therapy, like chemotherapy intensification, hematopoietic stem cell transplantation and optimized supportive care, could only get this far, but for the significant improvement of the outcome in pediatric AML, development of novel targeted therapy approaches is necessary. In recent years the advances in genomic techniques have greatly expanded our knowledge of the AML biology, revealing molecular landscape and complexity of the disease, which in turn have led to the identification of novel therapeutic targets. This review provides a brief overview of the genetic landscape of pediatric AML, and how it's used for precise molecular characterization and risk stratification of the patients, and also for the development of effective targeted therapy. Furthermore, this review presents recent advances in molecular targeted therapy and immunotherapy with an emphasis on the therapeutic approaches with significant clinical benefits for pediatric AML.

Risk-Stratified Therapy for Pediatric Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is the second most common type of leukemia in children. Recent advances in high-resolution genomic profiling techniques have uncovered the mutational landscape of pediatric AML as distinct from adult AML. Overall survival rates of children with AML have dramatically improved in the past 40 years, currently reaching 70% to 80% in developed countries. This was accomplished by the intensification of conventional chemotherapy, improvement in risk stratification using leukemia-specific cytogenetics/molecular genetics and measurable residual disease, appropriate use of allogeneic hematopoietic stem cell transplantation, and improvement in supportive care. However, the principle therapeutic approach for pediatric AML has not changed substantially for decades and improvement in event-free survival is rather modest. Further refinements in risk stratification and the introduction of emerging novel therapies to contemporary therapy, through international collaboration, would be key solutions for further improvements in outcomes.

[Survival efficacy of MDS/AML patients with TP53 abnormal received allogeneic hematopoietic stem cell transplantation]

Objective: TP53-abnormal MDS/acute myeloid leukemia (AML) patients' allogeneic hematopoietic stem cell transplantation (allo-HSCT) treatment's effectiveness and influencing factors should be studied. Methods: 42 patients with TP53 gene status change MDS/AML who underwent allo-HSCT from 2014.8.1 to 2021.7.31 at the Hematology Hospital of the Chinese Academy of Medical Sciences were the subject of a retrospective analysis. The 42 patients were divided into three groups: the TP53 deletion group (group A) , TP53 mono-alle mutation group (group B) , and TP53 multi-hit group (group C) . The differences in clinical features and prognostic factors after transplantation were analyzed. Results: There were 42 MDS/AML patients, including 21 patients with MDS, and 21 patients with AML. The median follow-up period was 34.0 (7.5-75.0) months and the median patient age at the time of transplantation was 41.5 (18-63) years old. The total OS was 66.3% (95% CI 53.4%-82.4%) in 3 years after transplantation, and EFS was 61.0% (95% CI 47.7%-78.0%) in 3 years. For 3 years after receiving hematopoietic stem cell transplantation, there were no statistically significant differences in 3-year OS and EFS in groups A, B, and C (P≥0.05) . The 3 years OS was 82.5% (95% CI 63.1%-100.0%) in group A, 60.6% (95% CI 43.5%-84.4%) in group B, and 57.1% (95% CI 30.1%-100.0%) in group C. Univariate analysis revealed that the number of co-mutant genes, pre-HSCT treatment, and disease type did not affect prognosis, while age, karyotype, co-mutation, positive blast cell before transplantation, and positive blast cell after transplantation were common prognostic factors for OS and EFS (P<0.1) . MRD levels before transplantation were found to be independent risk factors for OS (P=0.037, HR=33.40, 95% CI 1.24-901.17) in a multivariate analysis. Conclusion: Patients with MDS/AML who have TP53 mutations can benefit from allo-HSCT, but patients with complex karyotypes have a worse prognosis. Meanwhile, the final flow cytometry (FCM) monitoring blast cell test before HSCT has a certain guiding significance for prognostic assessment.

High-Risk Acute Myeloid Leukemia: A Pediatric Prospective

Pediatric acute myeloid leukemia is a clonal disorder characterized by malignant transformation of the hematopoietic stem cell. The incidence and the outcome remain inferior when compared to pediatric ALL, although prognosis has improved in the last decades, with 80% overall survival rate reported in some studies. The standard therapeutic approach is a combined cytarabine and anthracycline-based regimen followed by consolidation with allogeneic stem cell transplantation (allo-SCT) for high-risk AML and allo-SCT for non-high-risk patients only in second complete remission after relapse. In the last decade, several drugs have been used in clinical trials to improve outcomes in pediatric AML treatment.

The landscape of gene co-expression modules correlating with prognostic genetic abnormalities in AML

Background

The heterogenous cytogenetic and molecular variations were harbored by AML patients, some of which are related with AML pathogenesis and clinical outcomes. We aimed to uncover the intrinsic expression profiles correlating with prognostic genetic abnormalities by WGCNA.

Methods

We downloaded the clinical and expression dataset from BeatAML, TCGA and GEO database. Using R (version 4.0.2) and ‘WGCNA’ package, the co-expression modules correlating with the ELN2017 prognostic markers were identified (R² ≥ 0.4, p < 0.01). ORA detected the enriched pathways for the key co-expression modules. The patients in TCGA cohort were randomly assigned into the training set (50%) and testing set (50%). The LASSO penalized regression analysis was employed to build the prediction model, fitting OS to the expression level of hub genes by ‘glmnet’ package. Then the testing and 2 independent validation sets (GSE12417 and GSE37642) were used to validate the diagnostic utility and accuracy of the model.

Results

A total of 37 gene co-expression modules and 973 hub genes were identified for the BeatAML cohort. We found that 3 modules were significantly correlated with genetic markers (the ‘lightyellow’ module for NPM1 mutation, the ‘saddlebrown’ module for RUNX1 mutation, the ‘lightgreen’ module for TP53 mutation). ORA revealed that the ‘lightyellow’ module was mainly enriched in DNA-binding transcription factor activity and activation of HOX genes. The ‘saddlebrown’ module was enriched in immune response process. And the ‘lightgreen’ module was predominantly enriched in mitosis cell cycle process. The LASSO- regression analysis identified 6 genes (NFKB2, NEK9, HOXA7, APRC5L, FAM30A and LOC105371592) with non-zero coefficients. The risk score generated from the 6-gene model, was associated with ELN2017 risk stratification, relapsed disease, and prior MDS history. The 5-year AUC for the model was 0.822 and 0.824 in the training and testing sets, respectively. Moreover, the diagnostic utility of the model was robust when it was employed in 2 validation sets (5-year AUC 0.743–0.79).

Conclusions

We established the co-expression network signature correlated with the ELN2017 recommended prognostic genetic abnormalities in AML. The 6-gene prediction model for AML survival was developed and validated by multiple datasets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02914-2.