{'fraction_non_alphanumeric': 0.03711340206185567, 'fraction_numerical': 0.031844215349369986, 'mean_word_length': 4.956343792633015, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Increased expression of miR-22 corresponds to the high-risk subtypes of myelodysplastic syndromes and lower OS rate

The molecular basis for the development of myelodysplastic syndromes (MDS) has not been fully elucidated. The deregulated expression of microRNAs has been implicated in hematological disorders including MDS in recent years. An oncogenic role of miR-22 was suggested in the pathogenesis of MDS in which its expression was increased. MiR-22 was found to induce hypermethylation of the genome through targeting tumor suppressor TET2 in mouse hematopoietic stem cells, which triggered an increase in HSC self-renewal capability accompanied by defective differentiation and the development of a human MDS-like disease [1]. Another report showed that TET2 expression level and 5-hydroxymethylcytosine are decreased in refractory cytopenia of childhood and TET2 downregulation is inversely related to miR-22 expression [2]. However, there were reports showing that miR-22 was down-regulated in de novo acute myeloid leukemia (AML) and it may be a tumor suppressor in AML as well as in some other cancers [3–6]. In order to clarify the role of miR-22 during the initiation and progression of MDS, we examined the expression levels of miR-22 in the peripheral plasma as well as the CD34 (þ) progenitors of patients and evaluated its significance in different clinical contexts. A total of 45 patients with primary MDS and 15 with AML were enrolled in this study. The diagnosis of MDS and AML was made according to the criteria of 2016 WHO classifications. The subtypes of MDS patients included 12 cases of MDS with single lineage dysplasia (SLD), 9 cases of MDS with multi-lineage dysplasia (MLD), 7 cases of MDS with ring sideroblasts (RS), 17 cases MDS with excess blasts (including EB1 and EB2). Fifteen of newly diagnosed AML cases (untreated with chemotherapy) were also analyzed and included subtypes of AML with myelodysplasia-related changes (3) and AML not otherwise specified (NOS, 12), excluding subtypes with specific molecular lesions such as PML-RARA and RUNX1RUNX1T1, etc. Twenty cases of healthy donors were enrolled as normal control. Clinical characteristics of patients were summarized in Supplemental Table 1. Written informed consent for sample collection was obtained from all subjects enrolled. For the detection of circulating miR-22, EDTA-anticoagulated peripheral blood samples were collected and centrifuged. Circulating microRNAs were purified from the plasma with miRNeasy serum/plasma kit (Qiagen, Shanghai, China). For the detection of miR-22 and TET2 expression in MDS clonal cells, bone marrow CD34(þ) cells from MDS patients and healthy donor controls were purified using MACS CD34 Microbead kit and MiniMACS cell separator (Miltenyi Biotec, CA) according to manufacturer’s instructions, and microRNAs were purified using miRNeasy mini kit (Qiagen, Shanghai, China). cDNA was synthesized with TaqMan microRNA reverse transcription kit. Relative copy numbers of miR-22 was measured with real-time quantitative polymerase chain reaction assay using TaqMan miRNA assay kits for hsa-miR-22 and TET2 (Applied Biosystems, Shanghai, China). Expression of RNU6 was used as an internal control. The amplifications were performed on a 9700 ABI qPCR System. First of all, we confirmed that the expression of miR22 was detectable in the plasma of patients with MDS as well as that of healthy donors using routine stem-loop reverse transcription quantitative polymerase chain reaction. Our results showed that the expression levels of circulating miR-22 in MDS patient cohort were generally higher than that in the control cohort (45 cases vs 20 cases; medians: 1.637 vs 1.000; p1⁄4 .0166). Among them, 13 of the 45 MDS patients (37.1%) showed marked increase (>2 times) of miR-22 expression. However, no marked increase of miR-22 expression was detected in the AML cohort than controls (medians: 1.095 vs 1.000, p1⁄4 .1877) (Figure 1(A)). In accordance with this, the expression levels of miR-22 in the CD34 (þ) cells of MDS patients were also higher than healthy donor controls (N: 20 vs 20; medians: 1.524 vs 0.980; p1⁄4 .0179, Figure 1(B)). Because of the low percentage of blastic cells in the bone marrow of patients with MDS, the plasma or serum is more convenient to be obtained and to be detected for circulating microRNAs [7].