Microenvironment in acute myeloid leukemia: focus on senescence mechanisms, therapeutic interactions, and future directions.

Acute myeloid leukemia (AML) is a disease with a dismal prognosis, mainly affecting the elderly. In recent years, new drugs have improved life expectancy and quality of life, and a better understanding of the genetic-molecular nature of the disease has shed light on previously unknown aspects of leukemogenesis. In parallel, increasing attention has been attracted to the complex interactions between cells and soluble factors in the bone marrow (BM) environment, collectively known as the microenvironment.

Bone Marrow Microenvironment Involvement in t-MN: Focus on Mesenchymal Stem Cells.

Therapy-related myeloid neoplasms (t-MN) are a late complication of cytotoxic therapy (CT) used in the treatment of both malignant and non-malignant diseases. Historically, t-MN has been considered to be a direct consequence of DNA damage induced in normal hematopoietic stem or progenitor cells (HSPC) by CT. However, we now know that treatment-induced mutations in HSC are not the only players involved in t-MN development, but additional factors may contribute to the onset of t-MN.

Correlation analysis between auto-immunological and mutational profiles in myelodysplastic syndromes.

Objective And Design: Systemic-Inflammatory-Autoimmune-Diseases (SIAD) is increasingly considered in Myelodysplastic-Syndromes (MDS). In this line, we evaluated the MDS auto-immunological profile, correlating it to the mutational landscape, trying to identify a molecular-genetic trigger agent related to SIAD.

Methods And Materials: Eighty-one MDS were enrolled and t-NGS was performed.

Impairment of FOXM1 expression in mesenchymal cells from patients with myeloid neoplasms, de novo and therapy-related, may compromise their ability to support hematopoiesis.

Bone marrow mesenchymal stem cells (BM-MSCs) exhibit multiple abnormalities in myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML), including reduced proliferative and clonogenic capacity, altered morphology, impaired immunoregulatory properties and capacity to support hematopoiesis. Here, we investigated expression of the FOXM1 gene, a transcription factor driving G2/M gene expression, in BM-MSCs isolated from patients with MDS and AML, de novo and therapy-related, compared to BM-MSCs isolated from healthy donors (HD). We observed a statistically significant downregulation of FOXM1 expression in BM-MSCs isolated from MDS and AML patients, as compared to controls.

Atypical Rearrangements in APL-Like Acute Myeloid Leukemias: Molecular Characterization and Prognosis.

Acute promyelocytic leukemia (APL) accounts for 10-15% of newly diagnosed acute myeloid leukemias (AML) and is typically caused by the fusion of promyelocytic leukemia with retinoic acid receptor α () gene. The prognosis is excellent, thanks to the all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) combination therapy. A small percentage of APLs (around 2%) is caused by atypical transcripts, most of which involve or other members of retinoic acid receptors ( or ).

Clonal haematopoiesis as a risk factor for therapy-related myeloid neoplasms in patients with chronic lymphocytic leukaemia treated with chemo-(immuno)therapy.

Clonal haematopoiesis of indeterminate potential (CHIP) may predispose for the development of therapy-related myeloid neoplasms (t-MN). Using target next-generation sequencing (t-NGS) panels and digital droplet polymerase chain reactions (ddPCR), we studied the myeloid gene mutation profiles of patients with chronic lymphocytic leukaemia (CLL) who developed a t-MN after treatment with chemo-(immuno)therapy. Using NGS, we detected a total of 30 pathogenic/likely pathogenic (P/LP) variants in 10 of 13 patients with a t-MN (77%, median number of variants for patient: 2, range 0-6).

Mutational profile of ZBTB16-RARA-positive acute myeloid leukemia.

Background: The ZBTB16-RARA fusion gene, resulting from the reciprocal translocation between ZBTB16 on chromosome 11 and RARA genes on chromosome 17 [t(11;17)(q23;q21)], is rarely observed in acute myeloid leukemia (AML), and accounts for about 1% of retinoic acid receptor-α (RARA) rearrangements. AML with this rare translocation shows unusual bone marrow (BM) morphology, with intermediate aspects between acute promyelocytic leukemia (APL) and AML with maturation. Patients may have a high incidence of disseminated intravascular coagulation at diagnosis, are poorly responsive to all-trans retinoic acid (ATRA) and arsenic tryoxyde, and are reported to have an overall poor prognosis.

What's new in the pathogenesis and treatment of therapy-related myeloid neoplasms.

Therapy-related myeloid neoplasms (t-MNs) include diseases onsetting in patients treated with chemo- and/or radiotherapy for a primary cancer, or an autoimmune disorder. Genomic variants, in particular, in familial cancer genes, may play a predisposing role. Recent advances in deep sequencing techniques have shed light on the pathogenesis of t-MNs, identifying clonal hematopoiesis of indeterminate potential (CHIP) as a frequent first step in the multihit model of t-MNs.

From Clonal Hematopoiesis to Therapy-Related Myeloid Neoplasms: The Silent Way of Cancer Progression.

Clonal hematopoiesis (CH) has been recognized as a predisposing factor for the development of myeloid malignancies. Its detection has been reported at different frequencies across studies, based on the type of genome scanning approach used and the population studied, but the latest insights recognize its virtual ubiquitous presence in older individuals. The discovery of CH in recent years paved the way for a shift in the paradigm of our understanding of the biology of therapy-related myeloid malignancies (t-MNs).

Terminal deoxynucleotidyl transferase (TdT) expression is associated with FLT3-ITD mutations in Acute Myeloid Leukemia.

The terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase expressed in acute myeloid leukemias (AMLs), where it may be involved in the generation of NPM1 and FLT3-ITD mutations. We studied the correlations between TdT expression and FLT3-ITD or NPM1 mutations in primary AML samples, and the impact on patients' survival. TdT expression was analyzed in 143 adult AML patients by flow cytometry as percentage of positivity and mean fluorescence intensity (MFI) on blasts.

effect of eltrombopag alone and in combination with azacitidine on megakaryopoiesis in patients with myelodysplastic syndrome.

Thrombocytopenia is a severe complication for patients with myelodysplastic syndrome (MDS). Eltrombopag increases platelet count in MDS patients but its combination with azacitidine elicited controversial results. We aimed to quantify the colony forming units of megakaryocytes (CFU-Mk) obtained from CD34+ bone marrow cells isolated from patients with MDS and from healthy donors that were cultured in the presence or absence of azacitidine and with or without the sequential addition of eltrombopag to the culture medium.

Cytotoxicity and Differentiating Effect of the Poly(ADP-Ribose) Polymerase Inhibitor Olaparib in Myelodysplastic Syndromes.

Myelodysplastic syndromes (MDS) are highly heterogeneous myeloid diseases, characterized by frequent genetic/chromosomal aberrations. Olaparib is a potent, orally bioavailable poly(ADP-ribose) polymerase 1 (PARP1) inhibitor with acceptable toxicity profile, designed as targeted therapy for DNA repair defective tumors. Here, we investigated olaparib activity in primary cultures of bone marrow mononuclear cells collected from patients with MDS ( = 28).

Transcription factors implicated in late megakaryopoiesis as markers of outcome after azacitidine and allogeneic stem cell transplantation in myelodysplastic syndrome.

The hypomethylating agent azacitidine (AZA) is used to treat higher-risk myelodysplastic syndromes (HR-MDS) and elderly patients with low-blast count acute myeloid leukemia (LBC-AML). Platelet recovery is an early predictor of AZA response. We prospectively studied the expression profile of transcription factors, critical for late megakaryopoiesis and changes in their expression after AZA treatment in patients with HR-MDS and LBC-AML enrolled in the BMT-AZA trial (EudraCT number 2010-019673-15).

Mutational landscape of patients with acute promyelocytic leukemia at diagnosis and relapse.

Despite the high probability of cure of patients with acute promyelocytic leukemia (APL), mechanisms of relapse are still largely unclear. Mutational profiling at diagnosis and/or relapse may help to identify APL patients needing frequent molecular monitoring and early treatment intervention. Using an NGS approach including a 31 myeloid gene-panel, we tested BM samples of 44 APLs at the time of diagnosis, and of 31 at relapse.

The Role of Forkhead Box Proteins in Acute Myeloid Leukemia.

Forkhead box (FOX) proteins are a group of transcriptional factors implicated in different cellular functions such as differentiation, proliferation and senescence. A growing number of studies have focused on the relationship between FOX proteins and cancers, particularly hematological neoplasms such as acute myeloid leukemia (AML). FOX proteins are widely involved in AML biology, including leukemogenesis, relapse and drug sensitivity.

Therapy-related myeloid neoplasms: clinical perspectives.

Therapy-related myeloid neoplasms (t-MNs) are a complication of cytotoxic treatment for primary tumors and autoimmune diseases. t-MNs result from a complex interaction between individual predisposition and exposition to toxic agents. Some different biological and clinical characteristics can be recognized according to the type of anticancer drug.

Identification of i(X)(p10) as the sole molecular abnormality in atypical chronic myeloid leukemia evolved into acute myeloid leukemia.

The World Health Organization classifies atypical chronic myeloid leukemia (aCML) as a myeloproliferative/myelodisplastic hematological disorder. The primary manifestations are leukocytosis with disgranulopoiesis, absence of basophilia and/or monocytosis, splenomegaly and absence of Philadelphia chromosome or BCR/ABL fusion. Overall 50-65% of patients demonstrate karyotypic abnormalities, although no specific cytogenetic alterations have been associated with this disease.