{"doi":"10.1002/ctm2.1327","title":"Dissecting the cell of origin of aberrant SALL4 expression in myelodysplastic syndrome","abstract":"Dear Editor, Despite the increased reports on oncofetal protein Spalt like transcription factor 4 (SALL4) in myelodysplastic syndrome (MDS), the cellular identity of its aberrant expression in MDS patients remains unknown. Uncovering the answer to this question has important implications for furthering our understanding of the pathogenesis of MDS, as well as for the development of therapeutic targeting of SALL4 in MDS. Our study is the first to characterize aberrant SALL4 expression in MDS patient samples at a single cell level. Myelodysplastic Syndromes (MDS) are a heterogeneous group of diseases characterized by cytologic dysplasia and cytopenias resulting from ineffective hematopoiesis.1 Up to 30% of patients with MDS may transform to acute myeloid leukemia (AML). Despite the well-characterized cytogenetic changes and gene mutations associated with MDS, the pathogenesis of the disease remains incompletely understood, which is a major barrier to developing effective therapeutic strategies.1 SALL4, a transcription factor important for development and embryonic stem cell properties,2 is aberrantly expressed in various cancers3, 4 and is a known leukemic oncogenic driver.5-7 Its expression level serves as a prognostic biomarker for MDS at the time of diagnosis.8 We recently showed that SALL4 up-regulation following hypomethylating agent treatment in MDS patients correlates with poor outcomes.9 To further investigate the cellular identity of bone marrow cells with aberrant SALL4 expression in MDS patients, we utilized mass cytometry (CyTOF) to analyze MDS bone marrow cells in comparison to controls. Additionally, to address the relationship between SALL4 expression and somatic gene mutations, which is important for risk stratification and identification of disease drivers, we performed paired bone marrow Whole Exome Sequencing (WES) on these samples. DNA from bone marrow (BM) mononuclear cells from MDS and control samples (lymphoma without bone marrow infiltration) were extracted according to the manufacturer's recommendations (Table S1). We first examined SALL4 mRNA expression in MDS CD34+ cells by analyzing MDS expression profiles from the public database GSE19429, which contained 183 patients with MDS and 17 healthy controls. We observed that SALL4 expression in MDS CD34 cells was higher than that of controls, with the highest expression in refractory anemia with excess blasts type 2 (RAEB2) (p ≤ .05) (Figure 1A,B). To further investigate the protein expression pattern of SALL4 in MDS patients’ BM, we performed CyTOF experiments, which included 22 surface markers of cell surface proteins and 5 markers of intracellular signaling with single-cellular resolution (Table S2). We validated the CyTOF method in cell lines, using published gating methods (Figures S1 and S2). Our results showed that MDS patients had aberrant SALL4 protein expression in hematopoietic stem cells (HSC) (p ≤ .05), hematopoietic progenitor cells (HPC) (p ≤ .05) and myeloid lineage cells (p ≤ .05) when compared to controls (Figure 1C and Figure S2). Understanding the cell of origin with aberrant SALL4 expression has important implications for understanding MDS pathogenesis, as well as SALL4 therapeutic targeting in myeloid neoplasms. Recent advances in the understanding of myeloid neoplasm pathogenesis and refined analysis of AML bone marrow cell-of-origin studies have led to the design of therapeutic targeting of leukemia stem cells as a more promising approach toward a cure. Next, we investigated the relationship between SALL4 expression with p53, ki67, c-myc or phosphorylated AKT (pAKT), which have important roles in leukemia or MDS pathogenesis,1 on single cell level. SALL4 expressing cells expressed p53 (p = .01) in hematopoietic stem/progenitor (HSPC) (Figure 2A) and showed a trend of a higher level of pAKT and ki67. Next, FlowSOM via viSNE analysis was performed on MDS bone marrow cells to understand the expression pattern of SALL4 and p53 and to inve","journal":"Clinical and Translational Medicine","year":2023,"id":386533,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.95,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1012385,"name":"Miho Watanabe","orcid":"0009-0002-0764-2287","position":1,"is_corresponding":false},{"id":1012386,"name":"Jun Liu","orcid":"0000-0002-1546-0224","position":2,"is_corresponding":false},{"id":1012755,"name":"Kenji Tokunaga","orcid":null,"position":3,"is_corresponding":false},{"id":1012387,"name":"Eisaku Iwanaga","orcid":"0000-0001-5177-0070","position":4,"is_corresponding":false},{"id":644856,"name":"Yoshihiro Komohara","orcid":"0000-0001-9723-0846","position":5,"is_corresponding":false},{"id":574673,"name":"Emily M. Thrash","orcid":"0000-0002-3423-0336","position":6,"is_corresponding":false},{"id":315692,"name":"Mahmoud A. Bassal","orcid":"0000-0003-4322-2968","position":7,"is_corresponding":false},{"id":639152,"name":"Masao Matsuoka","orcid":"0000-0002-0473-754X","position":8,"is_corresponding":false},{"id":105565,"name":"Daniel G. Tenen","orcid":"0000-0002-6423-3888","position":9,"is_corresponding":false},{"id":105566,"name":"Li Chai","orcid":"0000-0003-1937-4750","position":10,"is_corresponding":false},{"id":1012384,"name":"Hiro Tatetsu","orcid":"0000-0001-8131-3401","position":0,"is_corresponding":true}],"reference_count":9,"raw_metadata":null,"created_at":"2026-07-19T01:18:00.717763Z","pmid":"37501279","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}