Pedigree investigation, clinical characteristics, and prognosis analysis of haematological disease patients with germline TET2 mutation.

BACKGROUND: Increasing germline gene mutations have been discovered in haematological malignancies with the development of next-generation sequencing (NGS), which is critical for proper clinical management and long-term follow-up of affected individuals. Tet methylcytosine dioxygenase 2 (TET2) is one of the most common mutations in haematological neoplasms. We aimed to compare the clinical characteristics of patients with germline and somatic TET2 mutations in haematological diseases and to analyse whether germline TET2 mutations have a family aggregation and tumour predisposition. METHODS: Out of 612 patients who underwent NGS of 34 recurrently mutated genes in haematological diseases, 100 haematological patients with TET2 mutations were selected for further study. Somatic mutations were detected by NGS in bone marrow/peripheral blood genomic DNA (gDNA). Germline TET2 mutations were validated in nail/hair gDNA by Sanger sequencing. Digital data were extracted from the haematology department of the West China Hospital of Sichuan University. TET2 mutation results were analysed by referencing online public databases (COSMIC and ClinVar). RESULTS: One hundred patients were studied, including 33 patients with germline and 67 patients with somatic TET2 mutations. For germline TET2 mutations, the variant allele frequency (VAF) was more stable (50.58% [40.5-55], P < 0.0001), and mutation sites recurrently occurred in three sites, unlike somatic TET2 mutations. Patients with germline TET2 mutations were younger (median age 48, 16-82 years) (P = 0.0058) and mainly suffered from myelodysplastic syndromes (MDS) (n = 13, 39.4%), while patients with somatic TET2 mutations were mainly affected by acute myeloid leukemia (AML) (n = 26, 38.8%) (P = 0.0004). Germline TET2 mutation affected the distribution of cell counts in the peripheral blood and bone marrow (P < 0.05); it was a poor prognostic factor for MDS patients via univariate analysis (HR = 5.3, 95% CI: 0.89-32.2, P = 0.0209) but not in multivariate analysis using the Cox regression model (P = 0.062). CONCLUSIONS: Germline TET2 mutation might have a family aggregation, and TET2 may be a predisposition gene for haematological malignancy under the other gene mutations as the second hit. Germline TET2 mutation may play a role in the proportion of blood and bone marrow cells and, most importantly, may be an adverse factor for MDS patients.

The m6A RNA methyltransferase METTL3/METTL14 promotes leukemogenesis through the mdm2/p53 pathway in acute myeloid leukemia.

N6-methyladenosine (m6A) is the most abundant internal modification in mammalian mRNA and recent studies have highlighted the importance of m6A levels in tumor development. In this study, we investigated the expression of methyltransferase-like 3 (METTL3) and 14 (METTL14), components of the RNA m6A methyltransferase complex, in samples from 89 patients with acute myeloid leukemia (AML), and followed the survival of 75 of these patients. Our results show that METTL3 and METTL14 are highly expressed in most of the patients with AML (except those with APL), and high levels of METTL3 and/or METTL14 correlated to shorter survival in the patients. In leukemia cell lines K562 and kasumi-1, both METTL3 and METTL14 promote cell proliferation and cell cycle, and the knockdown of METTL3 and METTL14 inhibits proliferation, and induces apoptosis and differentiation. Notably, the knockdown of METTL3 and METTL14 in K562 cell line leads to several changes in the expression of p53 signal pathway, including the upregulation of p53, cyclin dependent kinase inhibitor 1A (CDKN1A/p21), and downregulation of mdm2. Importantly, the m6A level of mdm2 mRNA was significant lower after knock-down of METTL3 and METTL14 examined by m6A-RIP and mdm2 qPCR assay, and the half-life of mdm2 under actinomycin-D treatment became shorter. Taken together, our study demonstrates that the lower m6A levels of mdm2 mRNA mediated by the knockdown of METTL3 and METTL14 could lead to the low stability of mdm2 mRNA transcripts and low expression of MDM2, in the end, activate p53 signal pathway. Both METTL3 and METTL14 play an oncogenic role in AML by targeting mdm2/p53 signal pathway.

Prognostic value of U2AF1 mutant in patients with de novo myelodysplastic syndromes: a meta-analysis.

U2 small nuclear RNA auxiliary factor 1 (U2AF1) mutant is the most common molecular biological abnormality in patients with myelodysplastic syndromes. Some studies have reported the prognostic impact of U2AF1 mutant in patients with de novo MDS, with discrepant results, so we do a meta-analysis about the relevant literatures to further investigate their prognostic impact on patients with de novo MDS. We conducted a literature search on databases such as PubMed, Embase, and the Cochrane Library to obtain studies on the prognosis of U2AF1 mutant in patients with de novo MDS published up to August 9, 2018. The primary endpoint was overall survival (OS), and the secondary endpoint was acute myeloid leukemia (AML) transformation. We extracted the hazard ratios (HRs) of OS and AML transformation and their 95% confidence intervals (CIs). Meta-analysis was performed by selecting a fixed-effect model or a random-effects model based on the heterogeneity between studies. A total of 14 cohort studies were included in the final meta-analysis, including 3322 patients with de no MDS, in which 390 patients were associated with U2AF1 mutant. The results showed that U2AF1 mutant had an adverse prognostic impact on OS (HR = 1.84, 95% CI: 1.45-2.33, P < 0.00001) and AML transformation (HR = 2.47, 95% CI: 1.50-4.06, P = 0.0004). U2AF1 mutant was associated with shorter OS in subgroup analyses of low- or intermediate-1-IPSS, U2AF1S34 and U2AF1Q157/R156. Out meta-analysis indicates that U2AF1 mutants are independent, detrimental prognostic factors for OS and AML transformation in patients with de novo MDS, as well as associating with shorter OS in subgroups of low- or intermediate-1-IPSS, U2AF1S34 and U2AF1Q157/R156. Further prospective studies are needed in the future, and subgroup analysis of U2AF1 subgroups is needed to obtain a more reliable basis for the impact of U2AF1 mutant on the prognosis of de novo MDS.

[Relationship of Cystic Fibrosis Transmembrane Conductance Regulator Expression with Clinical Features and Prognosis in Patients with Acute Leukemia].

OBJECTIVE: To investigate the expression of cystic fibrosis transmembrane conductance regulator (CFTR) protein in patients with acute leukemia and its relationship to clinical features and prognosis of acute leukemia. METHODS: A total of115 patients with acute leukemia were enrolled in the experimental group and 20 healthy individuals were used as control. Peripheral blood or bone marrow samples were collected, and mononuclear cells were isolated. The expression of CFTR protein was detected by Western blot. The relationships of CFTR protein expression to clinical features and prognosis was analyzed. RESULTS: The expression of CFTR protein was not detected in peripheral blood mononuclear cells of normal control, while it was positive in more than half of acute leukemias including acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), but negative in the patients with acute promyelocytic leukemia (M3). In the patients with AML, there was no difference in peripheral white blood cells (WBC), peripheral blast cells, platelet and hemoglobin (HGB) between CFTR-positive and CFTR-negative patients. There was no relationship between the expression of CFTR protein and gene mutations such as NPM1, CEBPA, FLT3-ITD, and C-Kit. Complete remission (CR) rate after two course in CFTR-negative patients was slightly higher than that in positive patients. The survival time of CFTR-negative patients was little longer than that of positive patients, but the difference was not statistically significant. CONCLUSIONS: The expression of CFTR protein seems not associated with clinical features, treatment response and prognosis in the patients with acute leukemia.

[Effect of dexamethasone contamination in drinking water on intestinal flora in mice].

OBJECTIVE: To evaluate the effect of water pollution with dexamethasone on intestinal flora in mice. METHODS: Twenty Balb/c mice were randomly divided into control group and low-, moderate- and high-dose dexamethasone groups. The mice in dexamethasone groups were exposed to dexamethasone sodium phosphate in drinking water at doses of 0.035, 0.225, and 2.25 ng for 36 days. The changes in behaviors, fur condition, and feces of the mice were observed daily. All the mice were sacrificed at 36 days and the tissues in the ileocecal region was collected for denaturant gradient gel electrophoresis (DGGE) of 16S rDNA V6 variable regions of microbes and sequence analysis with BLAST. RESULTS: The mice in the 3 dexamethasone groups all showed aggressive behaviors. Cluster analysis of DGGE graph showed relatively stable floras in the ileocecal region in all the mice, but principal component analysis identified differences in the dominating flora among the groups. Diversity analysis of the flora revealed significantly increased amount and types of bacteria in the intestinal flora in all the 3 dexamethasone groups (P<0.05 or 0.01) compared with the control group. Sequence analysis of 16S rDNA V6 regions showed 15 common bacterial species and 2 differential species between the dexamethasone groups and the control group with changes in the type and proportion of the dominating bacterium in the dexamethasone groups. Lactobacillus colonization was detected in the control group but not in moderate- and high-dose dexamethasone groups, and Shigella species were found in the latter two groups. CONCLUSIONS: Water contamination with dexamethasone can affect the nervous system of mice, cause changes in the types and amounts of intestinal bacteria and the dominating bacteria, and inhibit the colonization of probiotics in the intestinal floras to increase the risk of invasion by intestinal pathogenic bacteria.