Genetic mutations are an essential component of the pathogenesis of MDS. Different gene mutations lead to differences in survival outcomes and show a steady decrease in leukemia-free survival as the number of driving mutations increases. Therefore, gene mutations are of great significance for predicting the survival outcomes of MDS[2, 9]. However, there currently needs to be a unified standard for applying gene mutations in predicting the risk of MDS, and more clinical data analysis is needed to support the establishment of subsequent prognostic risk assessment models. In this study, we included 248 MDS patients to explore the relationship between gene mutations and survival outcomes in MDS patients. The research results indicate that ASXL1 gene mutation is an independent prognostic risk factor for MDS. ASXL1 is associated with normal hematopoiesis of hematopoietic stem cells, and this study also explores the mechanism of action of ASXL1 in MDS.
In our study, 69.7% of patients carried at least one gene mutation, with TET2 being the most common mutated gene (31%), followed by SF3B1 (26%), ASXL1 (23%), SRSF2 (14%), DNMT3A (12%), and RUNX1 (11%). Although the gene mutation rate differs from other studies[3], there is still a high proportion of TET2, SF3B1, and ASXL1 mutation rates. In addition, our further multivariate Cox regression analysis showed that except for the ASXL1 gene mutation, there was no significant correlation between other gene mutations and the prognosis of MDS. ASXL1 gene mutation is an independent prognostic factor for shorter survival outcomes in MDS. However, in previous studies, multiple studies have shown that SF3B1 mutations are independent factors associated with longer survival outcomes in MDS [10, 11], and TP53 and RUNX1 mutations are also associated with poor prognosis in MDS[4, 10, 12]. The differences in these research results may be due to insufficient sample size, and further large sample and multicenter studies are needed for validation.
In our study, there were 57 patients with ASXL1 mutations, of which 94.7% carried other gene mutations, with TET2 being the most common. Multiple gene mutations may affect the survival time under the background of ASXL1 mutations. We further analyze the survival time of gene co-mutations to obtain more accurate prognosis-related gene mutations. The survival analysis results showed that compared to ASXL1mt/ETV6wt and ASXL1mt/EZH2wt, patients with ASXL1mt carrying ETV6 or EZH2 gene mutations had a reduced survival time and a poorer prognosis. In the context of ASXL1 mutation, mutations in RUNX1 and SRSF2 do not affect patient survival outcomes, which differs from previous research results [13] These differences in research may be partly due to limitations in sample size and partly due to the presence of three or more gene mutations in some samples, which affect survival outcomes and require further clinical screening and validation.
ASXL1 gene mutations have been found in various myeloid tumors and are associated with poor clinical prognosis. Previous studies have shown that ASXL1 knockout mice can exhibit MDS-like phenotypes, such as decreased multi-lineage blood cells and decreased levels of H3K27me3 and H3K4me3 methylation[14]. Regarding the mechanism of ASXL1 mutation damaging hematopoietic function, Omar et al. Proposed that it is related to the inhibition of PCR2 recruitment[15]. However, its specific mechanism of action in MDS is still unclear, and further research is needed. We conducted bioinformatics analysis on samples from MDS patients, comparing the differences between ASXL1mt samples and samples without ASXL1mt. Combined with KEGG enrichment and IPP analysis, we found that the MYC gene exhibited a high presence in multiple KEGG enrichment pathways. The MYC oncogene is one of the pathogenesis mechanisms of lymphoma[16]. MYC is also commonly overexpressed in AML, which is a poor prognostic factor, and it is believed that the inactivation of PP2A is involved in MYC activation [17]. Reduced blood cells are a common clinical manifestation of MDS. Studies have shown that the absence of ASXL1 in mice can lead to excessive activation of MYC in granulocyte progenitor cells and red blood cell progenitor cells, hindering the maturation of neutrophils and red blood cells[18]MYC is associated with the occurrence of various cancers, and it is also involved in the process of blood cell maturation disorders in ASXL1 deficiency. Based on our research results, MYC may become a new therapeutic target for MDS patients with ASXL1 mutations. There is still a lack of molecular biological evidence on the mechanism by which ASXL1 gene mutations in MDS affect MYC function. Future research can focus on verifying this hypothesis.
Our study suggests that age, gender, and ASXL1 mutations are independent prognostic factors for overall survival in MDS patients. We also found that in the context of ASXL1 mutation, co-mutations of EZH2 or ETV6 significantly reduce the survival time of MDS patients and have a poor prognosis. In addition, KEGG enrichment and IPP analysis indicate that MYC, as a hub gene, may play an important role in MDS patients carrying ASXL1 mutations and is a potential therapeutic target that can be further validated through walking molecular biology experiments.