Introduction
Myeloid malignancies are a type of clonal disorders that arise from myeloid stem or precursor cells. These encompass the severe stages, like acute myeloid leukemia (AML), as well as the pre-leukemic phases, which include myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), and myelodysplastic syndromes (MDS). The advent of next-generation sequencing (NGS) in recent decades has facilitated a more profound comprehension of the molecular pathophysiology of myeloid neoplasms. This has led to the generation of valuable insights pertaining to disease diagnosis, classification, prognosis, and treatment [
1‐
3].
The DEAD/H-box helicase 41 gene (
DDX41), situated on chromosome 5q35, encodes a protein that functions as a DEAD-box-type RNA helicase. DDX41 comprises four domains: a Coiled coil domain, the two Rec-A like domains of the DEAD-box protein core, RecA1 and RecA2, termed DEAD and HelicC in DDX41 literature, and a Zn-finger domain. Two RecA-like domains contain ten conserved motifs. These ten conserved motifs are involved in ATP binding, ATP hydrolysis, nucleotide binding, and RNA unwinding activities [
4]. DDX41 plays a role in RNA conformational changes, including splicing of pre-mRNAs, excision of snoRNA-containing introns, modification of pre-rRNA processing, and interaction with R-loops [
5].
Heterozygous
DDX41 mutations in the human germline were first detected in multiple MDS and AML families [
6]. Through the use of next-generation sequencing technology, 28 different germline
DDX41 variants have been identified in 43 unrelated patients with MDS/AML [
7]. Pathogenic mutations in
DDX41 are detected in around 5% of instances of myeloid neoplasms [
8]. The
DDX41 mutation was identified as the underlying cause in 80% of myeloid tumors with a genetic background, representing 13% of the total cases [
9]. The majority of germline mutations occur in the N-terminus of the protein, predominantly within the DEAD domain, including nonsense, frameshift and missense mutations, which ultimately result in premature termination and truncated proteins, and give rise to protein-level amino acid alterations. Though one of the most prominent predisposition genes for myeloid malignancies is the
DDX41 mutation, the precise implications of
DDX41 mutations in myeloid malignancies remain unclear. For the purpose of precisely characterizing the prognostic significance of
DDX41 mutations in myeloid neoplasm patients and to clarify the associations between
DDX41 mutations and the clinicopathological features of myeloid neoplasms, we conducted a meta-analysis.
Methods
Literature registration
The Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) criteria were adhered to in the writing of the protocol. The registration number for the protocol in the database PROSPERO is CRD42024508577, and it is accessible via the following link.
Search strategy
The PubMed, the Cochrane Library, Embase, Web of Science, MEDLINE, and Google Scholar databases were used to conduct a systematic literature retrieval of the literature. Retrieval time of included studies is limited until January, 2024 and no language restrictions were applied in the research. The keywords included the following terms: DDX41 or DEAD-box helicase 41; myeloid neoplasms or acute myeloid leukemia or chronic myeloid leukemia or myelodysplastic syndrome. In order to identify any additional eligible publications, the references of key articles were inspected.
Literature selection criteria
Studies that fulfilled the specified criteria may be incorporated into the meta-analysis: (1)Any type of myeloid malignancies was involved; (2) The relationship between DDX41 mutations and the resulting clinical outcome; (3) Detailed survival information was provided on patients with DDX41 mutations to obtain overall survival (OS) data with a hazard ratio (HR) and 95% confidence interval (CI). If the data were not provided, we extracted survival data using the Kaplan–Meier curve. In light of multiple reports pertaining to a single study, our meta-analysis encompassed the publication of the highest quality.
Data extraction and quality assessment
The data were retrieved by two researchers operating as individual units, and any discrepancies were resolved through discussion among all investigators. The extracted information is as follows: the first author, year, country of the population enrolled, sample types, sample size, percentage of cases with normal karyotype, germline mutation type, subtype of myeloid neoplasms, concomitant mutations, patient’s age and gender demographics, white blood cells, hemoglobin, platelet count, bone marrow blasts, as well as HR and 95% CI of OS.
The methodological quality of the cohort studies included in this analysis was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). A NOS score of six or higher signifies that the study is well-conducted and of high quality.
Statistical analysis
Stata 17.0 software (Stata Corporation, College Station, Texas, USA) and Review Manager (version 5.3, the Cochrane Collaboration, Oxford, UK) were employed to perform the meta-analysis. The relationship between
DDX41 mutations and survival outcomes was evaluated using HR and 95% CI. In the absence of direct offers, the requisite data were extracted from Kaplan–Meier curves via Engauge Digitizer Version 4.1. The resulting rates of survival at particular intervals were then transcribed into the spreadsheet devised by Tierney JF et al. for the calculation of HRs and 95% CIs [
10]. Moreover, OR and 95% CI were chosen to estimate the relevance between
DDX41 mutations and clinicopathologic significance. The statistical heterogeneity among the studies was assessed utilizing a chi-squared (χ²) based Q test in conjunction with I² statistics. In the event that heterogeneity is deemed to be significant (
p < 0.1 or I² > 50%), a random effects model will be employed; if not, a fixed-effects model will be utilized [
11]. Publication bias was identified through the application of Egger’s and Begg’s tests, with a P-value of less than 0.05 indicating a significant presence of bias [
12].
Discussion
Virtually every facet of RNA metabolism is carried out by highly conserved enzymes designated as RNA helicases. The families of RNA helicases that are known to exist are DEAD-box, DEAH/RHA, Ski2-like, Upf1-like, and RIG-I [
31]. The highly conserved amino acid sequence Asp-Glu-Ala-Asp derived the name of DEAD-box proteins. These enzymes, which exhibit high degrees of conservation among diverse species, participate in a range of RNA-related processes, including ribosome biogenesis, pre-mRNA splicing, transcriptional control, translation, RNA export, and RNA degradation [
32]. Two domains resembling DNA recombination and repair protein A (RecA) make up the core of DEAD-box proteins. The DEAD-box protein DDX41 is distinguished by a disordered N-terminal region, a DEAD domain, and a Helicase domain. In patients with myeloid tumors, hereditary and sporadic mutations of
DDX41 have been identified [
21,
24].
DDX41 is a highly mutated gene associated with lengthy latency, severe illness, and a poor prognosis in familial AML/MDS [
6]. Despite
DDX41 having been recognized as a tumor-inhibitory gene in myeloid neoplasms, several experiments have assessed the predictive value of
DDX41 mutations in myeloid neoplasms, yet the results remain inconclusive [
6,
7].
The investigation was based on an analysis of 20 studies encompassing a total of 9,058 patients. Of the 20 retrospective studies, only 6 studies measured survival. As evidenced by the forest plots, meta-analyses have consistently demonstrated that DDX41 mutations are a powerful prognostic factor for favorable OS. A meta-analysis of existing literature indicates that, when compared with wild-type controls, DDX41 mutations are positively correlated with OS (HR 0.70, 95% CI 0.52–0.93, P = 0.01). Despite the significant heterogeneity (I2 = 69%), the sensitivity analysis shows that the meta-analysis’s outcomes were consistent and trustworthy. A comprehensive analysis was undertaken in order to elucidate the association between DDX41 mutations and myeloid neoplasms prognosis. The data was stratified based on disease type through the undertaking of subgroup analyses. The findings indicated a notable relationship between OS and the AML and MDS/AML cohorts, with pooled HR of 0.60 (95% CI: 0.41–0.87; I2 = 40%) and 0.66 (95% CI: 0.49–0.88; I2 = 31%), respectively. On the other hand, among MDS patients, nothing indicated a statistically significant link (HR 0.97, 95% CI 0.39–2.43, I² = 89%, P = 0.95). Nevertheless, there were only two studies included in the MDS/AML subgroup, and more research is necessary to determine the precise function of mutation detection in OS. It is important to highlight that no statistically significant correlation was identified in patients exhibiting DDX41 germline and somatic mutations (HR 0.56, 95% CI 0.12–2.62, I² = 91%, P = 0.46).
The DDX41 mutation appears to be connected to male sex, according to our meta-analysis (OR 3.41, 95% CI 1.78–6.54, I² = 41%, P = 0.0002). The study showed that DDX41 mutations are strongly linked to MDS prevalence (OR 1.57, 95% CI 1.29–1.91, I² = 0%, P < 0.00001), whereas no statistically significant correlation between DDX41 gene mutation and AML prevalence. This discrepancy may be attributed to the distinct molecular mechanisms underlying MDS and AML, DDX41 mutations may play a more prominent role in the early stages of myeloid malignancies, such as MDS, rather than in the more genetically complex AML. However, the lack of association with AML prevalence should be interpreted with caution, as it may also reflect the underrepresentation of other myeloid phenotypes, such as MPN, CCUS, and MDS/MPN, in our analysis. Future studies with larger and more diverse cohorts are needed to explore the potential role of DDX41 mutations in these phenotypes. In addition, no significant effect was found on age, AML prevalence, bone marrow characteristics, or white blood cell count.
Another prominent feature is that the frequency of normal karyotype was higher in
DDX41 mutation patients. Normal karyotype is associated with favorable prognosis in AML [
33], this may partially explain the longer survival observed in patients with
DDX41 mutations. While among abnormal karyotypes, the most prevalent is the complex karyotype, which is linked to poor prognosis in both AML and MDS [
34]. In the current analysis, p.M1I, p.D140fs and p.R525H are the most common germline
DDX41 mutations, which have multiple functions in the pathophysiology of a specific category of myeloid neoplasms [
35,
36]. Numerous oncogenic mutations have been shown to be prevalent in myeloid neoplasms by genomic profiling investigations. We have included the most often reported co-mutations in patients who have myeloid neoplasms accompanied by
DDX41 mutations.
ASXL1,
DNMT3A, and
TP53 were the three most often found co-mutations. It is presently unknown how precisely these co-mutations in
DDX41-mutated myeloid malignancies work. Nonetheless, a number of investigations have suggested that TP53-mutated
DDX41 mutations may be able to avoid triggering the DNA damage response system, cell cycle arrest, and death [
37,
38]. As a result, the ability to survive and undergo more clonal selection may facilitate malignant transformation.
Although this meta-analysis methodically compiles data emphasizing the critical function of DDX41 mutation as a prognostic factor in myeloid neoplasms, it is imperative to recognize its inherent limitations. Firstly, instead of being prospective research, all of the recruited studies were retrospective designs. A further limitation is that even though we reached out to the authors to request information, there was not enough data to provide statistical power to check for a link. Third, the direct calculation of the HR through the use of the analysis of variance may yield a more accurate result than the HR derived from the survival curve.
In conclusion, we found that OS for myeloid neoplasms is significantly impacted by DDX41 mutations. AML and MDS/AML were found to be substantially correlated with OS by subgroup screening. Moreover, male sex and DDX41 mutations were correlated. However, in order to draw a stronger conclusion, prospective randomized controlled trials with a greater diversity of myeloid neoplasm types and bigger sample numbers are required.
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