TET2 mutations contribute to adverse prognosis in acute myeloid leukemia (AML): results from a comprehensive analysis of 502 AML cases and the Beat AML public database.

Despite the high incidence of tet methylcytosine dioxygenase 2 (TET2) mutations in acute myeloid leukemia (AML), the prognostic implications of these mutations in three AML risk groups based on the 2022 ELN AML risk classification are still unclear. A total of 502 consecutive de novo AML patients who had next-generation sequencing data available between March 2011 and July 2021 at the Peking University Institute of Hematology were enrolled in this study. Univariate and multivariate Cox regression analyses were performed to explore the prognostic impact of TET2 mutations in the above cohort and the Beat AML cohort. Of the 502 total AML patients, 76 (15.1%) carried TET2 mutations. Multivariate analysis revealed TET2 mutations as independent risk factor for overall survival (OS) in both the total AML cohort (OR = 1.649, p = 0.009) and in the 2022 ELN intermediate-risk cohort (HR = 1.967, p = 0.05). Analysis of RNA-seq data from the Beat AML study revealed 1042 differentially expressed genes (DEGs) between the TET2-mutant and TET2 wild-type groups. The results of enrichment analysis indicated the DEGs to be notably enriched in categories related to the PI3K-Akt signaling pathway. Collectively, our findings indicate that mutations in TET2 are prognostically disadvantageous in AML patients. Assessment of TET2 mutational status contributes to the stratification of intermediate-risk AML patients. Multiple genes and pathways of potential therapeutic relevance may be differentially modulated by TET2 mutations in AML.

Prognostic impact of FLT3-ITD mutation on NPM1+ acute myeloid leukaemia patients and related molecular mechanisms.

The prognosis of acute myeloid leukaemia (AML) patients carrying NPM1 mutations is significantly worse when accompanied by FLT3-ITD mutations. However, accurate quantitative detection of FLT3-ITD mutations remains challenging. To identify a novel biomarker in NPM1+ FLT3-ITD+ AML patients for more accurate stratification, we analysed the differential gene expression between the NPM1+ FLT3-ITD+ and NPM1+ FLT3-ITD- groups in five public AML datasets and identified a biomarker by taking the intersection of differentially expressed genes. We validated this biomarker in bone marrow samples from NPM1+ AML patients at the Peking University Institute of Haematology and analysed its prognostic significance. BCAT1 expression was higher in the NPM1+ FLT3-ITD+ group than in the NPM1+ FLT3-ITD- group in all seven cohorts. BCAT1 was able to predict the prognosis of NPM1+ FLT3-ITD+ AML patients, and its predictive ability was superior to that of the FLT3-ITD allelic ratio (AR). FLT3-targeted inhibitor quizartinib reduced BCAT1 expression. BCAT1 knockdown using lentiviral vectors led to the downregulation of MYC expression. Thus, we identified BCAT1 as a novel biomarker for NPM1+ FLT3-ITD+ AML patients. The FLT3-ITD/BCAT1/MYC signalling pathway may play a biological role in promoting the occurrence and development of AML in FLT3-ITD+ cell lines.

The adverse impact of ecotropic viral integration site-1 (EVI1) overexpression on the prognosis of acute myeloid leukemia with KMT2A gene rearrangement in different risk stratification subtypes.

INTRODUCTION: AML patients with KMT2A-MLLT3 and other 11q23 abnormalities belong to the intermediate and high-risk level groups, respectively. Whether the poor prognostic value of Ecotropic Viral Integration site-1 (EVI1) overexpression suits either the subtypes of KMT2A-MLLT3 or Non-KMT2A-MLLT3 AML patients (intermediate and high risk group) needs to be further investigated. METHODS: We retrospectively analyzed the clinical characteristics of 166 KMT2A-r and KMT2A-PTD AML patients. RESULTS: For the Non-KMT2A-MLLT3 group, patients in the EVI1-high subgroup had shorter OS and DFS and higher CIR than those in the EVI1-low subgroup (p = .027, p = .018, and p = .020, respectively). Additionally, both KMT2A-MLLT3 and Non-KMT2A-MLLT3 patients who received chemotherapy alone had poorer prognosis than patients who also received allogeneic hematopoietic stem cell transplant (allo-HSCT) regardless of their EVI1 expression level (all p < .001). For transplanted patients with KMT2A-MLLT3 or Non-KMT2A-MLLT3 rearrangement, the EVI1-high subgroup had worse prognosis than the EVI1-low subgroup (all p < .05). The 2-year CIR of the KMT2A-MLLT3 and Non-KMT2A-MLLT3 groups with high EVI1 expression was high (52% and 49.6%, respectively). However, for patients with low EVI1 expression, the 2-year CIR of transplanted patients with KMT2A-MLLT3 and Non-KMT2A-MLLT3 was relatively low. CONCLUSIONS: Our study showed that for the Non-KMT2A-MLLT3 group, the EVI1-high group had shorter OS and DFS than the EVI1-low group. High EVI1 expression showed an adverse effect in AML with KMT2A rearrangement in different risk stratification subtypes. For the EVI1-high patients with non-KMT2A-MLLT3 rearrangement, other novel regimens towards relapse should be taken into consideration.

The Potential Roles of Mucosa-Associated Invariant T Cells in the Pathogenesis of Gut Graft-Versus-Host Disease After Hematopoietic Stem Cell Transplantation.

Gut acute graft-versus-host disease (aGVHD) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with high mortality. Mucosa-associated invariant T (MAIT) cells are a group of innate-like T cells enriched in the intestine that can be activated by riboflavin metabolites from various microorganisms. However, little is known about the function or mechanism of action of MAIT cells in the occurrence of gut aGVHD in humans. In our study, multiparameter flow cytometry (FCM) was used to evaluate the number of MAIT cells and functional cytokines. 16S V34 region amplicon sequencing analysis was used to analyze the intestinal flora of transplant patients. In vitro stimulation and coculture assays were used to study the activation and function of MAIT cells. The number and distribution of MAIT cells in intestinal tissues were analyzed by immunofluorescence technology. Our study showed that the number and frequency of MAIT cells in infused grafts in gut aGVHD patients were lower than those in no-gut aGVHD patients. Recipients with a high number of MAITs in infused grafts had a higher abundance of intestinal flora in the early posttransplantation period (+14 days). At the onset of gut aGVHD, the number of MAIT cells decreased in peripheral blood, and the activation marker CD69, chemokine receptors CXCR3 and CXCR4, and transcription factors Rorγt and T-bet tended to increase. Furthermore, when gut aGVHD occurred, the proportion of MAIT17 was higher than that of MAIT1. The abundance of intestinal flora with non-riboflavin metabolic pathways tended to increase in gut aGVHD patients. MAIT cells secreted more granzyme B, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ under the interleukin (IL)-12/IL-18 stimulation [non-T-cell receptor (TCR) signal] and secreted most of the IL-17 under the cluster of differentiation (CD)3/CD28 stimulation (TCR signal). MAIT cells inhibited the proliferation of CD4+ T cells in vitro. In conclusion, the lower number of MAIT cells in infused grafts was related to the higher incidence of gut aGVHD, and the number of MAIT cells in grafts may affect the composition of the intestinal flora of recipients early after transplantation. The flora of the riboflavin metabolism pathway activated MAIT cells and promoted the expression of intestinal protective factors to affect the occurrence of gut aGVHD in humans.