Pretransplantation Therapy with Hypomethylating Agents in Patients with Myelodysplastic Syndromes Receiving Reduced-Intensity Conditioning Regimens

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Novel superparamagnetic micro-devices based on magnetised PLGA/PLA microparticles obtained by supercritical fluid emulsion and coating by carboxybetaine-functionalised chitosan allowing the tuneable release of therapeutics

When superparamagnetic nanoparticles are loaded within micro-carriers of thermosensitive and injectable biopolymers, “smart” microdevices are obtained: they respond to an external magnetic field (EMF) through the release of any co-encapsulated molecules with a remote on-off control. Creating reliable and effective fabrication technologies for the production of these smart nano/micro-devices remains a challenge. In this work Supercritical Emulsion Extraction technology (SEE) is proposed for the fabrication of microcapsules with a core of poly-lactic-co-glycolic acid (PLGA) or poly-lactic acid (PLA) covered by carboxybetaine-functionalized chitosan (f-chi) and loaded with paramagnetic nanoparticles (MAG, mean size of 6.5±3.0 nm) and water soluble fluorescein (Fluo). Fluo is co-encaspulated as a fluorescent marker for the release study. Microcarriers showed a mean size of 800±60nm with an encapsulation efficiency of up to 90%. The inversion of surface charge, after the f-chitosan coating, suggested the presence of a uniform functionalized surface available for further chemical linkage. The external chitosan layer had a thickness of 200±50nm. An excellent MAG dispersion was confirmed within the biopolymer matrix that was shown to be responsive to EMF; indeed, Fluo was released over 3 or 5 days from PLGA or f-chiPLGA microdevices into PBS medium at 37°C; whereas, remote on-off controlled release was achieved when an Alternating Magnetic Field (AMF) was applie

Ultrastructural and functional differences between normal and tumor endothelial progenitor cells

Endothelial progenitor cells (EPCs) may be released from bone marrow to sustain the angiogenic switch that promotes tumor growth and metastatization of several solid cancers (Moccia et al., 2014). It has long been thought that tumor endothelium represents a rather stable structure, devoid of the genetic heterogeneity featuring neoplastic cells; however, more recent studies showed that tumor endothelial cells (TECs) present with an altered gene expression profile that bestows massive morphological and functional differences on them as compared to normal cells (Aird, 2012). Similarly, circulating EPCs isolated from individuals suffering from metastatic renal cellular carcinoma (mRCC) undergo a significant remodelling of their Ca2+ machinery, which is a master regulator of both angiogenesis and vasculogenesis. The present study clearly indicate that EPCs isolated from RCC (RCC-EPCs) and breast carcinoma (BC-EPCs) patients display ultrastructural and functional differences as compared to normal cells (N-EPCs)

Haploinsufficiency of RPS14 in 5q− syndrome is associated with deregulation of ribosomal- and translation-related genes

We have previously demonstrated haploinsufficiency of the ribosomal gene RPS14, which is required for the maturation of 40S ribosomal subunits and maps to the commonly deleted region, in the 5q− syndrome. Patients with Diamond-Blackfan anaemia (DBA) show haploinsufficiency of the closely related ribosomal protein RPS19, and show a consequent downregulation of multiple ribosomal- and translation-related genes. By analogy with DBA, we have investigated the expression profiles of a large group of ribosomal- and translation-related genes in the CD34+ cells of 15 myelodysplastic syndrome (MDS) patients with 5q− syndrome, 18 MDS patients with refractory anaemia (RA) and a normal karyotype, and 17 healthy controls. In this three-way comparison, 55 of 579 ribosomal- and translation-related probe sets were found to be significantly differentially expressed, with approximately 90% of these showing lower expression levels in the 5q− syndrome patient group. Using hierarchical clustering, patients with the 5q− syndrome could be separated both from other patients with RA and healthy controls solely on the basis of the deregulated expression of ribosomal- and translation-related genes. Patients with the 5q− syndrome have a defect in the expression of genes involved in ribosome biogenesis and in the control of translation, suggesting that the 5q− syndrome represents a disorder of aberrant ribosome biogenesis

The Role of the Iron Transporter ABCB7 in Refractory Anemia with Ring Sideroblasts

Refractory Anemia with Ring Sideroblasts (RARS) is an acquired myelodysplastic syndrome (MDS) characterized by an excess iron accumulation in the mitochondria of erythroblasts. The pathogenesis of RARS and the cause of this unusual pattern of iron deposition remain unknown. We considered that the inherited X-linked sideroblastic anemia with ataxia (XLSA/A) might be informative for the acquired disorder, RARS. XLSA/A is caused by partial inactivating mutations of the ABCB7 ATP-binding cassette transporter gene, which functions to enable transport of iron from the mitochondria to the cytoplasm. Furthermore, ABCB7 gene silencing in HeLa cells causes an accumulation of iron in the mitochondria. We have studied the role of ABCB7 in RARS by DNA sequencing, methylation studies, and gene expression studies in primary CD34+ cells and in cultured erythroblasts. The DNA sequence of the ABCB7 gene is normal in patients with RARS. We have investigated ABCB7 gene expression levels in the CD34+ cells of 122 MDS cases, comprising 35 patients with refractory anemia (RA), 33 patients with RARS and 54 patients with RA with excess blasts (RAEB), and in the CD34+ cells of 16 healthy controls. We found that the expression levels of ABCB7 are significantly lower in the RARS group. RARS is thus characterized by lower levels of ABCB7 gene expression in comparison to other MDS subtypes. Moreover, we find a strong relationship between increasing percentage of bone marrow ring sideroblasts and decreasing ABCB7 gene expression levels. Erythroblast cell cultures confirm the low levels of ABCB7 gene expression levels in RARS. These data provide an important link between inherited and acquired forms of sideroblastic anemia and indicate that ABCB7 is a strong candidate gene for RARS

P499: APPLICABILITY OF 2022 CLASSIFICATIONS OF ACUTE MYELOID LEUKEMIA IN THE REAL-WORLD SETTING

Background: The increasing knowledge of molecular characterization in acute myeloid leukemia (AML) led to the necessity to fully evaluate the genetic profile also for clinical purposes. These efforts resulted in the release of 2022 new editions of AML classification and prognostication systems, including the 5th edition of The World Health Organization (WHO) classification, the International Consensus Classification (ICC), and the European LeukemiaNet (ELN) recommendations for AML prognosis. Aims: We aimed to provide a real-world application of the WHO 2022, ICC and ELN 2022 classifications in the real-world setting, to unravel differences and similarities, and to test their implementation in clinical AML diagnosis. We particularly focused on secondary AML, myelodysplasia (MDS) related. Methods: We selected a cohort of 1001 cases diagnosed with AML according to the WHO 2016 and the ELN 2017 classifications. Where available (44.9% of cases), information concerning a previous history of an antecedent MDS or MDS/Myeloproliferative neoplasm (MPN), as well as a previous exposure to cytotoxic therapies were considered for defining secondary AML (s-AML) and therapy-related AML (t-AML), respectively. Survival outcome was available for 84.4% patients. Results: The overall diagnostic changes between the WHO 2016, compared to WHO 2022 and ICC classifications were 22.8% and 23.7% respectively, with a 13.1% difference in patients’ distribution between ICC and WHO 2022. The “not otherwise specified” (NOS) by ICC and “defined by differentiation” by WHO 2022 categories shrank compared to WHO 2016 (24.1% and 26.8% respectively, vs 38.7%), particularly due to an expansion of MDS-related categories. The 92.7% and the 74.4% of RUNX1-mutated AML were re-classified respectively by the ICC into AML with MDS-related gene mutations and by WHO 2022 into the AML myelodysplasia related (MR) category, although the latter considers RUNX1 mutations lacking of sufficient unifying characteristics. Of 397 cases with a MDS-related AML according to ICC, 55.9% were definable by the presence of a MDS-related karyotype. More than 75.0% of s-AML and t-AML cases presented a MDS-related genetic profile according to both new 2022 diagnostic classifications. The overall re-stratification between ELN 2017 and 2022 accounted for 12.9% (4.0% favorable to intermediate and 8.1% intermediate to adverse risk). The majority of s-AML and t-AML (83.1%) fell into the ELN 2022 adverse risk group. Stratifying the 213 AML classified as favorable risk by ELN 2017, the difference in OS between ELN 2022-defined favorable and intermediate risk groups was statistically significant (p<0.01). We also focused on the heterogeneous group of patients with normal karyotype and adverse risk mutations according to the ELN 2022: the survival outcome was significantly inferior in patients with multiple versus single MDS-related gene mutations (p<0.05). Summary/Conclusion: The 2022 revisions of AML classification led to a significant improvement of diagnostic schemes. In the real-world setting, conventional cytogenetics, usually easily available and less expensive than molecular characterization, correctly stratified 56% of AML MDS-related, thereby maintaining a diriment diagnostic role. Although the secondary nature of AML (prior MDS or MDS/MPN and therapy-related) is now applied as “diagnostic qualifiers”, it maintains a predictive role for defining an adverse outcome according to the ELN 2022. Considering the similarities between WHO and ICC diagnostic schemes, a tentative to generate a unified model taking into account practical and socio-economic issues is desirable

Complex Patterns of Chromosome 11 Aberrations in Myeloid Malignancies Target CBL, MLL, DDB1 and LMO2

Exome sequencing of primary tumors identifies complex somatic mutation patterns. Assignment of relevance of individual somatic mutations is difficult and poses the next challenge for interpretation of next generation sequencing data. Here we present an approach how exome sequencing in combination with SNP microarray data may identify targets of chromosomal aberrations in myeloid malignancies. The rationale of this approach is that hotspots of chromosomal aberrations might also harbor point mutations in the target genes of deletions, gains or uniparental disomies (UPDs). Chromosome 11 is a frequent target of lesions in myeloid malignancies. Therefore, we studied chromosome 11 in a total of 813 samples from 773 individual patients with different myeloid malignancies by SNP microarrays and complemented the data with exome sequencing in selected cases exhibiting chromosome 11 defects. We found gains, losses and UPDs of chromosome 11 in 52 of the 813 samples (6.4%). Chromosome 11q UPDs frequently associated with mutations of CBL. In one patient the 11qUPD amplified somatic mutations in both CBL and the DNA repair gene DDB1. A duplication within MLL exon 3 was detected in another patient with 11qUPD. We identified several common deleted regions (CDR) on chromosome 11. One of the CDRs associated with de novo acute myeloid leukemia (P=0.013). One patient with a deletion at the LMO2 locus harbored an additional point mutation on the other allele indicating that LMO2 might be a tumor suppressor frequently targeted by 11p deletions. Our chromosome-centered analysis indicates that chromosome 11 contains a number of tumor suppressor genes and that the role of this chromosome in myeloid malignancies is more complex than previously recognized

Relative response of patients with myelodysplastic syndromes and other transfusion-dependent anaemias to deferasirox (ICL670): a 1-yr prospective study

Objectives/methods: This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or beta-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC). Results: In patients with baseline LIC >= 7 mg Fe/g dry weight, deferasirox initiated at 20 or 30 mg/kg/d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 +/- 0.14 mg/kg/d; greatest in DBA: 0.4 +/- 0.11 mg/kg/d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety/tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases. Conclusions: Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups