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AML-associated cytogenetic abnormalities (inv (16), del (16), t(8;21)) in patients with myelodysplastic syndromes.

Evidence suggests that prognosis in patients with myelodysplastic syndromes (MDS) or acute myelogenous leukemia (AML) depends more on karyotype than on formal classification as either MDS or AML according to the French-American-British (FAB) system. We provide further evidence of overlap between these two entities, reporting 4 patients who presented with either inv(16) (p13q22), del(16) (q22), or t(8;21) despite an FAB diagnosis of MDS rather than the diagnosis of AML with which these abnormalities are generally associated. In 3 patients, disease was relatively long-standing (3-10 months) prior to diagnosis, suggesting that the association between MDS and these cytogenetic abnormalities may not merely reflect a transient phenomenon. Two patients with inv(16) and the MDS subtype refractory anemia with excess blasts in transformation (RAEB-t) received AML-type chemotherapy as did a patient with t(8;21) and RAEB-t. All entered CR paralleling the high CR rate seen in patients with AML and these abnormalities. Our data support the concept that MDS and AML may be different manifestations of the same disease.

Adolescent↗

WP-1034, a novel JAK-STAT inhibitor, with proapoptotic and antileukemic activity in acute myeloid leukemia (AML).

Cytokine stimulation induces proliferation and growth of acute myeloid leukemia (AML) blasts and high levels of cytokines have been associated with poor prognosis in AML. The Jak-Stat pathway constitutes a major mediator of cytokine activity. We investigated whether WP-1034, a novel Jak-Stat inhibitor, is active against AML blasts. OCIM2 and fresh AML cells were incubated with 1 to 6 microM WP-1034 to determine its effect on proliferation. WP-1034 effectively inhibited proliferation of OCIM2 cells and fresh AML samples. We then analyzed the expressions of Stat 1, 3, and 5, as well as Phospho-Stat 1, 3, and 5 by Western immunoblotting after incubation of OCIM2 cells without and with 1 to 10 microM WP-1034 for 2 hours, and at 5 microM from 20 minutes up to 4 hours and found that WP-1034 blocked Stat 3 and 5 activation. Analysis of cell cycle status by PI staining and flow cytometry showed that WP-1034 caused cell cycle arrest of OCIM2 cells in sub-Go phase. We then evaluated the induction of apoptosis of OCIM2 cells following incubation with WP-1034 at 3 to 6 microM by annexin V-CY5 assay and analyzed caspase 3 and PARP cleavage using Western immunoblotting. We found that WP-1034 induced apoptosis of OCIM2 cells and that induction of apoptosis involved cleavage of caspase 3 and the DNA repair enzyme poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP). Taken together, our data suggest that WP-1034 is a potent inhibitor of AML cell proliferation by inhibition of Stat 3 and 5 and induction of caspase-dependent apoptosis.

Acrylamides↗

[The absence of monocyte-granulocyte antigen expression in a case of AML].

The brief record of a 25 y. o. male patient with AML (FAB M1) is shown, in whom the blast cells did not express any of the 5 myeloid antigens or the other-lineage related antigens, as detected with the monoclonal antibodies. The blast cells were induced to express CD13 antigen after a short-term culture in vitro. This result suggests that CD13 antigen can be expressed virtually by all AML cells, since CD13 antigen is known to cover fresh AML cells at the highest incidence. No unusual clinical feature was noted in this patient as AML case. The collected documentation of antigen-free AML cases seems necessary for the relevant understanding of AML heterogeneity.

Adult↗

Effect of AML serum on normal human myeloid differentiation and hexamethylene bisacetamide-induced granulocytic differentiation of the human HL-60 promyelocytic leukaemic cell line.

The effect of serum from 32 AML patients on the normal human myeloid differentiation and the hexamethylene-bisacetamide induced granulocytic differentiation of HL-60 promyelocytic leukaemic cell line was studied. Nonadherent normal mononuclear marrow cells were cultured in vitro at a concentration of 5 x 10(5) cells/ml for 6 days with each of the 32 AML sera. Ten normal human AB sera were used as control. The results showed an inhibitory activity on both morphological and functional differentiation of normal human myeloid immature marrow cells by 29 out of the 32 AML sera tested. These 29 AML sera were added to cultures of HL-60 (2.5 x 10(5)/ml) leukaemia cell line which incorporated 2 mM hexamethylene-bisacetamide for 6 days. The results showed no significant inhibition of hexamethylene-bisacetamide induced granulocytic differentiation by any of the 29 AML sera. The efficacy of hexamethylene-bisacetamide in inducing differentiation in the presence of inhibitory factors suggests a possible role in the treatment of AML patients.

Acetamides↗

[Altered expression of protooncogenes during clinical course in an AML case transformed from MDS].

The changes of expression of oncogenes in the mononuclear cells of MDS case was studied during his clinical course, in series. His bone marrow was considered to maintain its function partly in initial stage, since both peripheral blood and bone marrow responded to clinical episodes. However, his hematopoietic function was gradually impaired with the disease evolution to AML. We examined the expression of four oncogenes in the mononuclear cells of his three clinical stages, early RAEB-t, RAEB-t and AML, to study the cause of transformation from MDS to AML. Early RAEB-t cells expressed all oncogenes studied other than c-myb, while only c-myc was weakly observed in RAEB-t. AML cells expressed c-myc, c-jun and c-myb, except for c-fms. The expression of c-fms and c-jun of early RAEB-t was considered to reflect the monocytosis induced by infections, and the expressions of c-myb and c-myc of AML cells were regarded as one of malignant signs of tumor transformation. These findings suggest that the evolutional transformation of MDS to AML was affected by the altered expression of oncogenes.

Anemia, Refractory, with Excess of Blasts↗

Functional domains of the t(8;21) fusion protein, AML-1/ETO.

The AML-1/ETO fusion protein is created by the (8;21) translocation, the second most frequent chromosomal abnormality associated with acute myeloid leukemia. In the fusion protein the AML-1 runt homology domain, which is responsible for DNA binding and CBF beta interaction, is linked to ETO, a gene of unknown function. The primary sequences of the runt homology domain indicates no known DNA binding motifs, but is predicted to contain six beta-strands, two alpha-helices and a nucleotide binding motif. Mutagenesis of AML-1/ETO was performed to delimit the functional domains of the chimeric protein. Most mutations in the runt homology domain that resulted in reduced CBF beta binding also inhibited DNA binding, indicating that the DNA and CBF beta binding sequences are tightly linked. However, these activities were separated by a point mutation of residue 144, within the putative ATP binding motif, which nearly eliminated DNA binding, but did not affect CBF beta binding. Random mutagenesis identified the hydrophobic face of the amphipathic fifth beta-strand, adjacent to the putative ATP binding motif, as critical for both DNA and CBF beta binding. C-terminal deletion mutants of AML-1/ETO indicated that ETO sequences are essential for interference with AML-1B-mediated transcriptional activation, and that residue 540 defines the C-terminal boundary of a potential repression domain. Thus, these mutational analyses define the regions of AML-1/ETO which regulate its function and that may be important in promoting leukemia.

Adenosine Triphosphate↗

Residual normal, highly proliferative progenitors can be isolated from the CD34+/33- fraction of AML with a more differentiated phenotype (CD33+).

Since in AML differentiation is abnormal but not absent, a hierarchy of stem cells, progenitor cells and more differentiated cells is postulated. The leukemic stem cell might also be characterized by the expression of CD34 and the absence of differentiation markers. Bone marrow samples of 33 AML patients, including 10 patients both at presentation and after relapse, were double labeled for CD34 and CD33. In 14/33 AML less than 1% of the labeled cells were found in the CD34+/33- fraction. After relapse a certain shift towards a more primitive phenotype was observed, but in 4/5 relapsed AML the CD34+/33- fraction remained below 1%. Single cells from the different subfractions were cultured and showed heterogeneous cluster and colony growth in both the CD34-/33+ and CD34+/33+ fraction. More colonies were observed in the CD34+/33- fraction. In AML with a more 'mature' phenotype (low number of CD34+/CD33- cells), highly proliferative myeloid, erythroid and mixed colonies could be cloned exclusively from this small CD34+/33- fraction. In five patients with numerical chromosomal abnormalities all these highly proliferative colonies appeared disomic using in situ hybridization (ISH) with centromeric probes. Based on these data we conclude that the CD34+/33- cell fraction in AML with a more mature immunophenotype (small fraction of cells CD34+/33-) comprise residual normal progenitors, while no primitive leukemic progenitors could be identified.

Acute Disease↗

GM-CSF enhances IL-2-activated natural killer cell lysis of clonogenic AML cells by upregulating target cell expression of ICAM-1.

Acute myeloid leukemia (AML) cells express the surface adhesion proteins intercellular adhesion molecule-1 (ICAM-1, CD54) and lymphocyte function associated molecule-3 (LFA-3, CD58). Exposure to the myeloid growth-promoting cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulates expression of ICAM-1 and LFA-3 on AML cells but does not increase their sensitivity to lysis by interleukin-2-activated natural killer cells (LAK) in 51Cr assays. However when AML cells are exposed to GM-CSF prior to incubation with LAK, their subsequent clonogenic activity is significantly reduced. If a blocking antibody to ICAM-1 is added during the incubation period of AML with LAK, the inhibitory effect is completely ablated. A less pronounced effect is observed with an antibody to LFA-3. ICAM-1 is expressed on a greater proportion of CD34+ than CD34- AML cells and exposure to GM-CSF induces a significantly greater upregulation of ICAM-1 on leukemic CD34+ cells than their CD34- counterparts. These data suggest that the inhibitory effect of IL-2-activated natural killer cells on clonogenic AML cells is mediated principally via the lymphocyte function associated molecule-1 (LFA-1)/ICAM-1 interaction. Interleukin-2 upregulates LFA-1 expression on natural killer cells. Simultaneous administration of effector cell activators such as IL-2 and target cell modulators such as GM-CSF may have a therapeutic benefit in patients with minimal residual myeloid leukemia.

Adult↗

Modulation of cell proliferation and cytokine production in AML by recombinant interleukin-1 receptor antagonist.

In Acute Myelogenous Leukemia (AML), Interleukin 1 (IL-1) might sustain autocrine and paracrine loops of leukemic growth. An IL-1 inhibitor has been recently purified and cloned. This molecule binds to the IL-1 receptors but has no IL-1 like activity fulfilling the characteristics of a pure Interleukin-1 receptor antagonist (IL-1ra). We studied the in vitro effect of human recombinant IL-1ra on proliferation of AML blasts. Spontaneous as well as IL-1 stimulated AML proliferation was significantly inhibited by the addition of 50 ng/ml of recombinant IL-1ra in a dose dependent manner. The inhibitory effect of IL-1ra was measurable after 12 hours of culture and reached a plateau at 60 hrs. We found that IL-1ra could compete with IL-1 in binding to specific IL-1 receptors on AML cells. As expected, culture supernatants of unstimulated leukemic samples contained IL-1 beta and GM-CSF activity. The incubation of the same leukemic blasts with IL-1 ra was followed by reduction or disappearance of GM-CSF in culture supernatants whereas the IL-1 beta production was only partially modulated. By Northern blot experiments performed on freshly isolated, uncultured leukemic blasts, we found a constitutive expression of the IL-1 beta gene in 19 of 23 AML cases analyzed. On the contrary, only three of these patients express the IL-1 RA mRNA. All together these results suggest that imbalanced secretion of IL-1 and its natural receptor antagonist could contribute to the unrestricted growth of AML cells.

Cell Division↗

Expression of multidrug resistance-associated protein (MRP) mRNA in blast cells from acute myeloid leukemia (AML) patients.

A specific and quantitative reverse-transcription polymerase chain reaction (RT-PCR) assay was developed for measuring the mRNA of the multidrug resistance-associated protein (MRP). A region corresponding to bp 3897-4471 of MRP cDNA is amplified, which encompasses approximately half of the second nucleotide-binding domain (NBD2). In two multidrug resistant (MDR) sublines of the HL-60 human acute myeloid leukemia (AML) cell line which overexpress MRP but not P-glycoprotein, the assay detects elevated levels of MRP mRNA (4- to 8-fold) relative to the drug-sensitive parental cells (designated HL-60/W). Blast cells from 24 patients with AML were also studied for MRP expression using this RT-PCR method. Expression of MRP was normalized for that of beta-actin in the blast cells, which was also determined by RT-PCR. All of these blast cell samples had MRP expression that was detectable after 35 PCR cycles. Eighteen of these patients samples had levels of expression of MRP mRNA equal to or less than that expressed by HL-60/W cells. In six patient blast cell specimens, the expression of MRP mRNA was up to 1.7-fold higher than that of HL-60/W cells. In 21 specimens, the steady-state intracellular accumulation of daunorubicin (1 microgram/ml, 3h) was also determined. The blast cells with MRP mRNA expression higher than HL-60/W had a lower median accumulation of daunorubicin compared to those whose MRP expression was less than HL-60/W, suggesting a functional defect in drug transport in the cells with higher MRP expression; a similar trend toward lower daunorubicin accumulation was also noted in the one-third of samples that displayed the highest expression of MDR1 mRNA (also determined by RT-PCR). These studies illustrate the range of expression of MRP in AML blast cell specimens. The identification of MRP overexpression in MDR AML cell lines and in some AML patient blast cells with low intracellular daunorubicin accumulation warrants further study of MRP as a component of clinical drug resistance in AML.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

More individual markers are necessary for patients with acute myeloid leukemia (AML). Does cytomorphology or cytogenetics define the biological entity?

The biology of AML is reflected through several prognostic factors. Until now there has been no general agreement about these factors. In most studies therapy is not stratified according to risk factors with the exception of age. Since 1976 the FAB classification has been the basis for the diagnosis in AML. But only for the AML M3 is this important for the choice of treatment. Therefore, it is unclear if the FAB classification is the best way to describe the individual biology in AML. We are able to verify that significant differences in remission rates and event-tree survival are much better reflected by the cytogenetic results. With data from the AML cooperative group on one hand and in a kind of meta-analysis with cytogenetic date from different studies on the other hand, we are able to conclude that cytogenetics are much more feasible to describe the biological entity in AML patients. Further studies should focus more on this individual prognostic factor.

Acute Disease↗

Immunophenotyping is an independent factor for risk stratification in AML.

BACKGROUND: Chromosomal abnormalities are one of the most important prognostic factors in acute myeloid leukemia (AML). However, only a limited number of patients have such informative chromosomal abnormalities. The prognostic value of immunophenotyping in this disease is still unclear. METHODS: Seven hundred and eighty-three newly diagnosed AML patients treated in the German SHG-AML trials in 1991 and 1996 were analyzed with a panel of 33 antibodies. Expression was correlated to overall survival, complete remission-rate, and complete remission duration, and tested in a multivariate analysis including other clinical and biological markers. RESULTS: With a median follow-up of 4.3 years, patients with AML blasts negative for CD9, CD11b, CD13, CD34, and CD41, or positive for CD15, CD33, CD38, CD64, and MPO had superior overall survival. This effect was associated with a significantly higher complete remission rate (CD13, CD34, CD41, and CD64) or a longer complete remission duration (CD9, CD11b, and CD64). Cox-regression analysis, including cytogenetic, morphologic, and biologic parameters showed CD9, CD13, CD34, and CD64 as independent factors for overall survival. These markers were used for a prognostic score. Patients were pooled in three groups with highly significant differences of overall survival. The prognostic relevance of this score was confirmed in patients with normal karyotype and/or in younger patients </= 60 years. CONCLUSIONS: Immunophenotyping is not only helpful for diagnosis but is of independent significance for prognosis, and may be useful for risk stratification in AML patients.

Acute Disease↗

Integrating multi-omics approaches in acute myeloid leukemia (AML): Advancements and clinical implications.

Acute myeloid leukemia (AML) is a highly heterogeneous and aggressive hematologic malignancy characterized by clonal proliferation of myeloid precursors. Despite significant advancements in genomic profiling and targeted therapies, patient outcomes remain suboptimal due to disease complexity, resistance mechanisms, and high relapse rates. The integration of multi-omics approaches-spanning genomics, epigenomics, transcriptomics, proteomics, and metabolomics-has revolutionized AML research, offering a comprehensive understanding of leukemogenesis, tumor heterogeneity, and therapeutic vulnerabilities. Recent studies leveraging high-throughput sequencing, mass spectrometry, and advanced computational tools have uncovered novel biomarkers, clonal evolution dynamics, and microenvironmental interactions that drive AML progression and resistance. For instance, single-cell multi-omics has revealed chemotherapy-resistant leukemic stem cell populations, while proteogenomic analyses have identified actionable targets such as MCL1 and metabolic dependencies like OXPHOS. Clinically, integrated omics platforms are refining risk stratification, minimal residual disease (MRD) monitoring, and personalized therapy selection. However, challenges such as data integration complexity, cost barriers, and ethical considerations remain. This review highlights the transformative potential of multi-omics in AML, emphasizing recent advancements in technology, biomarker discovery, and therapeutic innovation. By bridging the gap between molecular insights and clinical practice, multi-omics integration promises to redefine AML management, paving the way for precision oncology and improved patient outcomes.

Humans↗

Risk-adapted postremission therapy in acute myeloid leukemia: results of the German multicenter AML HD93 treatment trial.

The objective of the AML HD93 treatment trial was to evaluate the outcome in young adults with acute myeloid leukemia (AML) after postremission therapy was stratified according to cytogenetically defined risk. The rationales for the study design were based (i) on previous favorable results with high-dose cytarabine in AML with t(8;21), inv/t(16q22) and in AML with normal karyotype, and ii) on encouraging results obtained in several phase II trials using autologous stem cell transplantation (SCT). Between July 1993 and January 1998, 223 eligible patients, 16-60 years of age with newly diagnosed AML other than French-American-British type M3/M3v, were entered into the trial. Risk groups were defined as follows: low risk: t(8;21) or inv/t(16q22); intermediate risk: normal karyotype; high risk: all other chromosomal abnormalities. Following intensive double induction therapy with idarubicin, cytarabine and etoposide, all patients in complete remission (CR) received a first consolidation therapy with high-dose cytarabine and mitoxantrone (HAM). A second consolidation therapy was stratified according to the risk group: low risk: HAM; intermediate risk: related allogeneic SCT or sequential HAM; high risk: related allogeneic or autologous SCT. Double induction therapy resulted in a high CR rate of 74.5%, and 90% of the responding patients were eligible for consolidation therapy. Survival for all 223 trial entrants was 40%, and for the 166 patients who entered CR, disease-free (DFS) and overall survival were 40 and 51% after 5 years, respectively. Within the low-, intermediate- and high-risk groups, DFS and survival after 5 years were 62.5 and 87, 40 and 49 and 17 and 26% respectively, without advantage for allogeneic transplantation in the intermediate- and high-risk groups. Postremission therapy-related mortality was 0, 7 and 14%, respectively. This study demonstrates the feasibility of cytogenetically defined risk-adapted consolidation therapy. The overall trial results are at least equivalent to those of published trials supporting the risk-adapted treatment strategy.

Acute Disease↗

[Neuropsychological sequelae in children with AML treated with or without prophylactic CNS-irradiation].

BACKGROUND: In study AML-BFM 87 the relapse rate was lower in patients receiving cranial irradiation (CRT). However, CRT has always been associated with adverse cognitive side effects. Therefore, the impact of CRT on neuropsychological function in children with AML was retrospectively evaluated. PATIENTS: We tested 53 children (30 boys, 23 girls) treated according to the AML-BFM-87 protocol (median age at diagnosis: 8.5 years, range 0.3 - 17.5; median time since diagnosis: 5.7 yrs, 3.8 - 10.7 yrs). To avoid any bias from additional therapy elements, patients with relapse or initial CNS involvement and transplanted patients were excluded (n=32). Our cohort was representative of the total group of 104 long term survivors of study AML-BFM 87. CNS prophylaxis consisted of ARA-C i.th., high dose ARA-C i. v. and either no CRT (n=15) or CRT (n=38) at a dose of 12 - 18 Gy depending on age. METHODS: Neuropsychological function was evaluated by psychological tests of attention and concentration (test d2 by Brickenkamp) and an intelligence test (Progressive Matrices by Raven). In addition, patients and their parents were interviewed about the occurrence of learning problems, subjective deficits in concentration and physical impairment. RESULTS: In the total group, no significant differences were seen between irradiated and non-irradiated patients regarding the psychological tests. However, the irradiated patients scored below the non-irradiated control group in test "d2" (concentration: 41st vs. 59th percentile). In the interview, irradiated patients tended to report more learning problems (lp) (10/36 vs. 1/14; p=0.15) and subjective deficits in concentration (con). In irradiated girls (con: 6/15 vs. 0/8; p=0.06; lp: 5/15 vs. 0/8; p=0.12) and younger patients (0 - 5 years at diagnosis; con: 7/12 vs. 2/9; p=0.18; lp 3/10 vs. 1/9; p=0.18) this trend was even more pronounced. CONCLUSION: Children with AML and CRT had no significant intellectual impairment in standardized tests when compared to non-irradiated patients. However, more irradiated patients reported learning problems and subjective concentration deficits.

Adolescent↗

Prediction of therapy-related acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) after autologous bone marrow transplant (ABMT) for lymphoma.

Therapy-related acute myelogenous leukemia and myelodysplastic syndrome (t-AML/MDS) are being reported with increasing frequency as a complication of ABMT for Hodgkin's disease and non-Hodgkin's lymphoma. At present there is no method available to predict who is at risk or is destined to develop this nearly universally fatal disorder. We therefore investigated whether clonal growth of cells is predictive of the development of t-AML/MDS. In a patient who developed secondary AML/MDS 18 months after ABMT, X-linked clonality analysis at the human androgen receptor locus was performed on serial banked samples, and documented transition from polyclonal to clonal hematopoiesis. Clonal cells could be identified 6 months after transplant (1 year prior to the diagnosis of t-AML/MDS), at a time when there was no morphologic or clinical evidence of disease. Clonality analysis can be predictive of the development of t-AML/MDS after ABMT and may offer important insights into associated risk factors and strategies to minimize the risk of t-AML/MDS.

Alleles↗

Chromosomes and causation of human cancer and leukemia. XVII. Banding studies in acute myeloblastic leukemia (AML).

Chromosomes were studied in the bone marrow and/or blood cells from 38 patients with acute myeloblastic leukemia (AML). The initial analysis with conventional Giemsa staining revealed that 16 of the 38 patients with AML studied had chromosomal abnormalities. The cells of these 38 patients (16 with abnormal karyotypes and 22 with normal karyotypes) were re-examined with Q- and G-banding techniques. Twenty-two patients with conventionally stained normal karyotypes did not show any abnormalities, even with banding techniques. Three cases had a common translocation between the long arm of No. 8 and No. 21, i.e., [t(8;21)(q22;q22)], the so-called prototypic karyotype. Two cases had a 45, XX,-21 karyotype; and three cases had trisomy of the long arm of chromosome No. 1. The banding patterns revealed that in two of the three latter cases, the presence of the trisomy of the long arm of No. 1 apparently occurred late in the disease. Therefore, it is possible that the trisomy of the long arm of No. 1 might bear a relationship to selective growth advantage of the leukemic cells in some cases with AML. The presence of extra No. 8 and No. 9 chromosomes and deletion of the long arm of No. 7, frequently reported in several leukemic disorders, were also found in the present cases, but with other chromosomal abnormalities. Chromosomes No. 6,No. 15,No. 19,No. 20, and X were not involved in any structural and/or numerical changes. The present data suggest that some chromosomal changes are nonrandom in AML and that further chromosomal studies may lead to a division of AML patients into subgroups on the basis of their karyotypes.

Adult↗

The Germline SH2B3rs111340708 Splicing Variant Drives Intron Retention and Protein Instability by Impacting Clinical Outcomes in Core Binding Factor AML.

The SH2B3 gene, also known as LNK, encodes an adaptor protein that negatively regulates key hematopoietic signaling pathways, including JAK-STAT, MAPK, and PI3K/AKT, thereby maintaining hematopoietic homeostasis. SH2B3 interacts with major signaling regulators such as JAK2, MPL, FLT3, and KIT. Loss-of-function alterations have been reported in several hematologic malignancies, supporting its role as a leukemia predisposition gene. We previously identified a germline start-loss mutation (c.3G&#xa0;>&#xa0;A) in SH2B3 in a family with early-onset myeloproliferative neoplasm, demonstrating that this variant causes SH2B3 haploinsufficiency. In the present study, next-generation sequencing of 149 de novo AML patients identified a frequent intronic polymorphism (rs111340708), located within intron 6 (IVS6) of SH2B3. Although this variant has a reported minor allele frequency (MAF) of approximately 12% in European populations, it was enriched in our AML cohort, reaching 34.2% in Core Binding Factor leukemias (CBFLs). The presence of the rs111340708 variant was associated with inferior overall survival, whereas no significant association with progression-free survival was observed. Functional analyses demonstrated that this polymorphism promotes aberrant IVS6 intron retention in AML cells, resulting in reduced abundance of correctly spliced SH2B3 transcripts and predicted generation of truncated peptides and/or nonsense-mediated decay. Consistently, immunoblot analyses of AML patient samples and hematologic cell lines revealed heterogeneous SH2B3 protein expression, including additional SH2B3-immunoreactive species in variant carriers, together with reduced levels of the canonical SH2B3 protein. Collectively, these findings identify a common germline splicing polymorphism as a novel mechanism contributing to SH2B3 functional impairment in AML and highlight the potential relevance of non-coding variants in leukemia pathogenesis, with possible implications for risk stratification and future therapeutic strategies.

Humans↗