Background/Objectives: Myeloproliferative neoplasms are a group of clonal myeloid malignancies that affect bone marrow and include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). PV is caused in most patients by the JAK2-V617F mutation and is characterized at the phenotypic level by overproduction and accumulation of red blood cells. PV is associated with significant morbidity, including risk of thrombotic events and of hematologic evolution (myelofibrotic or leukemic transformation) and reduced survival. In addition to the JAK2-V617F mutation, PV patients display additional molecular abnormalities. The aim of this study is to review recent studies investigating molecular abnormalities observed in PV. Methods: An extensive search of the most recent literature was performed, selecting and critically analyzing the most relevant studies. Results: The studies carried out in recent years have provided an extensive molecular analysis of PV, showing its heterogeneity, characterized in many patients by the presence of additional cytogenetic and gene mutations that contribute to the disease development and evolution. Conclusions: PV is a complex disease that needs to be carefully characterized at the molecular level at diagnosis, to be monitored in time to predict the risk for thrombotic complications and hematologic evolution and to receive an adequate treatment.

Background/Objectives: Myeloproliferative neoplasms are a group of clonal myeloid malignancies that affect bone marrow and include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). PV is caused in most of patients by the JAK2-V617F mutation and is characterized at phenotypic level by overproduction and accumulation of red blood cells. PV is associated with significant morbidity, including risk of thrombotic events and of hematologic evolution (myelofibrotic or leukemic transformation) and reduced survival. In addition to JAK2-V617F mutation, PV patients display additional molecular abnormalities. The aim of this study is to review recent studies investigating molecular abnormalities observed in PV. Methods: An extensive search of the most recent literature was performed, selecting and critically analyzing the most relevant studies. Results: The studies carried out in the last years have provided an extensive molecular characterization of PV, showing its heterogeneity, characterized in many patients by the presence of additional cytogenetic and non-driver gene mutations that contribute to the disease development and evolution. Conclusions: PV is a complex disease that needs to be carefully characterized at molecular level at diagnosis, to be monitored in time to predict the risk for thrombotic complications and hematologic evolution and to receive an adequate treatment.

Background/Objectives: In recent years there has been a consistent development of clinical studies surrounding the incorporation of the B-cell lymphoma 2 (BCL-2) inhibitor venetoclax (VEN) into the treatment of acute myeloid leukemia (AML) Methods: A search of the literature showed a tremendous development of experimental and clinical studies evaluating the impact of VEN-based regimens in the treatment of AML patients. This review comprehensively analyzes the available scientific evidence—including prospective clinical trials, retrospective cohorts, and real-world studies—to summarize current knowledge on the efficacy and safety of venetoclax-based regimens in AML patients. Results: Recent studies have evaluated VEN-based regimens in newly diagnosed (ND) and refractory/relapsed (R/R) AML patients, showing the efficacy of these treatments. VEN with hypomethylating agents (HMAs) became the standard-of-care for elderly/unfit AML patients. Recent studies strongly support the effectiveness of VEN-based regimens in frontline treatment of adult AML patients eligible for intensive treatments. VEN-based therapies were also used in combination with targeted therapies, thus generating triplet therapeutic regimens that are under evaluation for the treatment of some AML subtypes. However, the response to VEN+HMAs is highly variable and in part depends on tumor genetics; some patients are resistant or relapse following VEN-based treatments and future studies will be required to develop therapeutic strategies able to circumvent resistance and to identify patients at high risk of relapse. Prospective randomized trials are required to establish the real efficacy of VEN in various clinical settings and to refine maintenance and discontinuation strategies, aiming to improve long-term outcomes and to make more safe treatments based on VEN.

β-thalassemia and sickle cell disease are two inherited hematological diseases due to defective hemoglobin synthesis or to the production of hemoglobin with altered properties. These two conditions have prolonged survival with modern support therapies, albeit life-long, complex, expensive and resource-consuming. Studies carried out in the last three decades have shown that allogeneic hematopoietic stem cell transplantation (allo-HSCT) and gene therapy may offer a curative approach for these diseases. Allo-HSCT should be performed early in life to reduce disease-related complications like irreversible tissue damage due to iron overload in patients with transfusion-dependent β-thalassemia (TDT) and systemic vasculopathy in patients with sickle cell disease (SCD). HSCTs from a matched-sibling donor or a matched-unrelated donor represent the best therapeutic option; however, haploidentical HSCT in both TDT and SCD is now increasingly performed as a valuable and viable option for a larger number of these patients. An alternative curative strategy is based on gene therapy. These curative approaches, particularly those of gene therapy, are available only in a part of the world. Gene therapy diffusion is strongly limited by its high technological and infrastructure requirements and its very high cost. Criteria must be defined for the optimal selection of TDT and SCD patients for allo-HSCT or gene therapy.

Background: Chromosomal rearrangements involving lysine methyltransferase 2A (KMT2A) define a genetically distinct subset of acute myeloid leukemia (AML) in 10% of cases in adult patients; the frequency of KMT2A-r is higher in pediatric AML. Translocations involving the KMT2A locus at chromosome 11q23 result in the formation of a chimeric oncogene partner, where the N-terminal part of KMT2A is fused to a variety of translocation partners. The leukemogenic activity of KMT2A-fusion partners is related to their capacity to hyperactivate the expression of HOX-A and MEIS1 target genes, which stimulate the proliferation of hematopoietic stem cells. The oncogenic activity of KMT2A fusion proteins requires the binding with Menin, and this interaction can be targeted pharmacologically by small molecules acting as potent and selective Menin inhibitors. Methods: A search of the literature showed a marked development of experimental studies exploring the molecular pathogenesis of AML with KMT2A-r and of clinical studies evaluating new induction intensive treatments and the development of a targeted therapy based on Menin inhibitors. Results and Conclusions: In the present review article, we summarize our current understanding of the biology of KMT2A-r in AML development and the recent consistent progress made in the treatment of KMT2A-r AML through new chemotherapy regimens and targeted therapy using Menin inhibitors. However, the prognosis of older KMT2A-r AML patients remains poor and could be improved by drug combination studies including Menin inhibitors. Many encouraging observations derived from ongoing clinical trials with Menin inhibitors need to be confirmed through randomized clinical trials.

Complete or partial deletions of chromosome 7 (-7/del7q) represent the most frequent chromosomal abnormalities observed in myeloid neoplasms (MNs) and are associated with a poor prognosis. -7/del7q is observed in 10–15% of adult patients with myelodysplasia (MDS) or with acute myeloid leukemia (AML). The occurrence of -7/del7q is particularly frequent in pediatric MDS, often associated with germline mutations of GATA2 or SAMD9/SAMD9L genes. The disease biology of -7/del7q and the genes driving leukemic development have not been completely elucidated, but the haploinsufficiency of tumor suppressor genes located in chromosome 7 deleted regions seems to play a relevant role. The response to standard treatments based either on chemotherapy or hypomethylating agents plus Venetoclax is limited. No approved targeted therapies exist for patients with -7/del7q; however, some recent studies have discovered some vulnerabilities of these myeloid neoplasms than can be efficiently targeted.

Background/Objectives: Sickle cell disease (SCD) and β-thalassemia are autosomal recessive disorders of erythroid cells due to gene mutations occurring at the level of the β-globin gene. The severe forms of these hemoglobinopathies observed in individuals homozygous for these defective genes need intensive treatments, are associated with a poor quality of life, and allogeneic hematopoietic stem cell represents the only curative treatment option that can be offered to a limited proportion of patients. Methods: This work is a narrative review supported by a systematic literature search and analysis. Results: To bypass this limitation, autologous hematopoietic stem cell transplantation has been developed in these patients, in which patients' HSCs are harvested and genetically modified ex vivo, then transplanted back into patients after conditioning for stem cell transplantation. There are two different approaches for gene therapy of hemoglobinopathies, one based on gene addition or gene silencing using lentiviruses as vectors and the other based on gene editing strategies using CRISPR-Caspase 9 technology or base editing. Several gene therapy products have been successfully evaluated in these patients, achieving transfusion independence and correction of hematological abnormalities durable over time. Conclusions: Several gene therapy products have been approved for the treatment of SCD and β-thalassemic patients and offer potentially curative treatment for these patients.

The only cytogenetic alteration defining a subtype of a myelodysplastic syndrome is represented by the deletion of the long arm of chromosome 5 (del(5q)), now classified as MDS with isolated del(5q). This subtype is associated with a peculiar phenotype mainly dependent on the haploinsufficiency of several genes located on the deleted arm of chromosome 5. These patients show a good prognosis and respond to treatment with lenalidomide, but some cases progress to acute myeloid leukemia. Molecular studies have, in part, elucidated the heterogeneity of MDS with isolated del(5q), mainly related to the association with different co-mutations that may affect leukemic transformation and survival. In other MDS patients, del(5q) is combined with other chromosomal abnormalities, giving rise to a condition of complex karyotype, associated with frequent TP53 mutations and with a poor prognosis. Two different molecular pathways seem to be responsible for the generation of MDS with isolated del(5q) or of MDS with del(5q) associated with a complex karyotype.

The development of molecular profiling approaches for AML patients such as whole genome sequencing, whole exome sequencing and transcriptomic sequencing have greatly contributed to better understanding of leukemia development, progression and treatment responsiveness/resistance. These studies have generated a new knowledge about driver events operating in AML that can be translated into clinics, thus favoring the mutations; using this approach, more than 50% of older AML patients display molecular alterations, such as IDH1, IDH2, FLT3 (FLT3-TKD and FLT3-ITD), NPM1 and KMT2A rearrangements that can be targeted by specific drugs. Preclinical and clinical studies have supported the use of drugs targeting these molecular alterations as first-line therapy in association with induction chemotherapy in chemotherapy-fit patients or with a hypomethylating agent in association with a Bcl-2 inhibitor (Venetoclax) in chemotherapy-unfit patients. These studies have shown promising results that need to be confirmed through randomized clinical studies specifically involving the enrollment of older AML patients.

Acute myeloid leukemia (AML) is characterized by the clonal expansion of myeloid progenitors blocked at various stages of their differentiation process, and drugs that bypass this differentiation block are therapeutically efficient, as shown by retinoic acid and arsenic trioxide in acute promyelocytic leukemia. However, the successful application of differentiation therapy in APL has not translated into clinical benefit for other non-APL subtypes of AML, in which intensive chemotherapy regimens represent the standard of care. However, the development of molecular studies has led to the identification of therapeutic targets (such as mutated proteins and deregulated pathways) and has led to the generation of a new category of specific pharmacologic agents. Some of these agents, such as inhibitors of mutant isocitrate dehydrogenase (IDH1 and IDH2), lysine-specific demethylase-1 (LSD1), and Menin, have shown the capacity to induce leukemic cell differentiation and with significant therapeutic efficacy.

Chimeric antigen receptor (CAR) T-cell therapy has improved the outcomes of patients with relapsed/refractory B-cell lymphomas, B-cell acute lymphoblastic leukemia, and multiple myeloma. However, CAR-T cell therapy is also associated with distinct toxicities that contribute to morbidity and mortality. A large number of studies now define the different toxicities associated with CAR-T cell therapy and have, in part, clarified their mechanisms. In particular, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are the two main acute toxicity events that occur after CAR-T cell infusion. Other CAR-T-related toxicities occur later after CAR-T cell infusion and include B-cell aplasia, hypogammaglobulinemia, infections, and cytopenias. Infections represent the main cause of non-relapse death observed in patients undergoing CAR-T cell therapy. Second primary malignancies are rare and are mainly represented by myeloid malignancies.

Iron is required for several vital biological processes in all human cells. In mammals, a considerable number of proteins are involved in iron metabolism and utilize iron in many essential cellular processes, such as oxygen transport, mitochondrial respiration, gene regulation, and DNA synthesis or repair. Iron metabolism is a complex system finely regulated at both systemic and cellular levels. It involves the development of specialized mechanisms for iron absorption, transport, recycling, storage, and export, and protection against toxic compounds that can be generated during iron redox cycling in the presence of oxygen. The erythropoietic compartment consumes the majority of iron to support the high demand for hemoglobin synthesis. A tightly regulated system enables efficient iron uptake by erythroid cells and its subsequent processing for the synthesis of large amounts of heme, which is then incorporated into hemoglobin. A bidirectional regulatory system between erythropoiesis and iron metabolism ensures precise coordination between the two processes. This regulation is often disrupted in various anemic conditions.

The clinical use of T lymphocytes engineered with chimeric antigen receptors (CARs) has revolutionized the treatment of patients with refractory or relapsed hematological malignancies. CAR natural killer (CAR-NK) cells are NK cells engineered with CARs to specifically target cell antigens expressed on the membrane of tumor cells. CAR-NK cells could offer some advantages with respect to CAR-T cells, related to their specific and innate anti-tumor activity, availability as an “off the shelf” cellular therapy, reduced costs, and improved safety. Promising efficacy of CAR-Nk cell therapy was observed in clinical trials based on the treatment of some hematological malignancies. However, to date, the clinical experience of CAR-NK cell therapy has been preliminary, with the evaluation of only a limited number of patients. Furthermore, CAR-NK cell therapy has been limited by the short persistence of these cells and by the suboptimal cytotoxic activity of some CAR-NK preparations. Therefore, studies based on the enrollment of a number of patients is required to carefully assess and confirm the safety and the efficacy of CAR-NK cell therapy in hematological malignancies and to compare their efficacy with respect to allogeneic CAR-T cells.

Background/Objectives: Sickle cells disease (SCD) and -thalassemia are autosomal recessive disorders of erythroid cells due to gene mutations occurring at the level of the -globin gene. The severe forms of these hemoglobinopathies observed in individuals homozygous for these defective genes need intensive treatments, are associated with a poor quality of life and allogeneic hematopoietic stem cell represents the only curative treatment option that can be offered only to a limited proportion of patients. Methods: This work is a narrative review supported by a systematic literature search and analysis. Results: To bypass this limitation, autologous hematopoietic stem cell transplantation has been developed in these patients in which patients’ HSCs are harvested and genetically modified ex vivo, then transplanted back into patients after conditioning for stem cell transplantation. There are two different approaches for gene therapy of hemoglobinopathies’, one based on gene addition or gene silencing using lentiviruses as vectors and the other based on gene editing strategies using CRISPR-Caspase 9 technology or base editing. Several gene therapy products have been successfully evaluated in these patients achieving transfusion independence and correction of hematological abnormalities durable in the time. Conclusions Several gene therapy products have been approved for the treatment of SCD and -thalassemic patients and offer a potentially curative treatment for these patients.

Clonal hematopoiesis (CH) is an age-related process in which hematopoietic stem/progenitor cells increase their fitness due to the acquisition of mutations that lead to a proliferative advantage and to clonal expansion. Its frequency increases with age, and it mostly affects people older than 70 years. The most mutated genes in CH are epigenetic regulators, DNA damage response genes, and splicing factors, which are all involved in the development of myeloid neoplasia. Some risk factors, including age, smoking, and prior cytotoxic therapy, increase the risk of developing CH or increase the fitness of CH. Various types of CH have been observed, associated or not with cytopenias or monocytosis. CH represents a risk factor for many pathological conditions and particularly for hematologic malignancies. A better understanding of the risks related to CH has triggered the development of research, translational, and clinical programs for the monitoring, prevention, and treatment of CH.

Chimeric antigen receptor T cells (CAR-Ts) have shown a remarkable efficacy in hematological malignancies but limited responses in solid tumors. Among solid tumors, CAR-T cell therapy has been particularly explored in brain tumors. CAR-T cells have shown a limited clinical efficacy in various types of brain tumors due to several factors that have hampered their activity, including tumor antigen heterogeneity, the limited access of CAR-T cells to brain tumor cells, limited CAR-T cell trafficking and in vivo persistence and the presence of a highly immunosuppressive tumor microenvironment. Despite these considerations, some recent studies have shown promising antitumor activity of GD2-CAR-T cells on diffuse midline gliomas and neuroblastomas and of CARv3-TEAM-E cells in glioblastomas. However, strategies are required to improve the effect of CAR-T cells in brain tumors, including advanced CAR-T cell design with multiple antigenic targeting and incorporation of combination therapies.

The transformation of acute promyelocytic leukemia (APL) from the most fatal to the most curable subtype of acute myeloid leukemia (AML), with long-term survival exceeding 90%, has represented one of the most exciting successes in hematology and in oncology. APL is a paradigm for oncoprotein-targeted cure.APL is caused by a 15/17 chromosomal translocation which generates the PML-RARA fusion protein and can be cured by the chemotherapy-free approach based on the combination of two therapies targeting PML-RARA: retinoic acid (RA) and arsenic. PML-RARA is the key driver of APL and acts by deregulating transcriptional control, particularly RAR targets involved in self-renewal or myeloid differentiation, also disrupting PML nuclear bodies. PML-RARA mainly acts as a modulator of the expression of specific target genes: genes whose regulatory elements recruit PML-RARA are not uniformly repressed but also may be upregulated or remain unchanged. RA and arsenic trioxide directly target PML-RARA-mediated transcriptional deregulation and protein stability, removing the differentiation block at promyelocytic stage and inducing clinical remission of APL patients.

Blinatumomab, a CD19-CD3 bispecific T cell engager (BiTE), has two recombinant single-chain variable fragments that temporarily link CD3+ T cells and CD19+ B cells, leading to the T cell-mediated lysis of neoplastic B cells. Improved minimal residual disease (MRD)-negative response rates and long-term overall survival have been observed in B-ALL patients who received this drug. These therapeutic successes have led to FDA approval for refractory/relapsed and MRD-positive B-ALL patients. Furthermore, recent studies in newly diagnosed B-ALL patients have led in Philadelphia chromosome-positive patients to the development of chemotherapy-free regimens based on tyrosine kinase inhibitors plus Blinatumomab and in Philadelphia chromosome-negative patients to improvement in outcomes using chemotherapy regimens that have incorporated Blinatumomab in the consolidation phase of treatment.

Multiple myeloma (MM) is a disorder of the monoclonal plasma cells and is the second most common hematologic malignancy. MM initiation and progression are dependent upon complex genomic abnormalities. The current pathogenic model of MM includes two types of primary events, represented by chromosome translocations or chromosome number alterations resulting in hyperdiploidy. These primary molecular events are observed both in MM and in monoclonal gammopathy, its premalignant precursor. Subsequent genetic events allow the progression of monoclonal gammopathy to MM and, together with primary events, contribute to the genetic complexity and heterogeneity of MM. Newer therapies have considerably improved patient outcomes; however, MM remains an incurable disease and most patients experience multiple relapses. The dramatic progresses achieved in the analysis of the heterogeneous molecular features of different MM patients allowed a comprehensive molecular classification of MM and the definition of an individualized prognostic model to predict an individual MM patient’s response to different therapeutic options. Despite these progresses, prognostic models fail to identify a significant proportion of patients destined to early relapse. Treatment strategies are increasingly. Based on disease biology, trials are enriched for high-risk MMs, whose careful definition and categorization requires DNA sequencing studies. Keywords: Multiple Myeloma; Chromosome Abnormalities; Molecular Events; Mutations.

The incidence of melanoma, the most lethal form of skin cancer, has increased mainly due to ultraviolet exposure. The molecular characterization of melanomas has shown a high mutational burden led to the identification of some recurrent genetic alterations. BRAF gene is mutated in 40–50% of melanomas and its role in melanoma development is paramount. BRAF mutations confer constitutive activation of MAPK signalling. The large majority (about 90%) of BRAF mutations occur at amino acid 600; the majority are BRAFV600E mutations and less frequently BRAFv600K, V600D and V600M. The introduction of drugs that directly target BRAF-mutant protein (BRAF inhibitors) and of agents that stimulate immune response through targeting of immune check inhibitor consistently improved the survival of melanoma BRAFV600-mutant patients with unresectable/metastatic disease. In parallel, studies in melanoma stage II-III patients with resectable disease have shown that adjuvant therapy with ICIs and/or targeted therapy improves PFS and RFS, but not OS compared to placebo; however, neoadjuvant therapy plus adjuvant therapy improved therapeutic response compared to adjuvant therapy alone.