Endothelial cell activation by myeloblasts: molecular mechanisms of leukostasis and leukemic cell dissemination

Important Considerations in the Intensive Care Management of Acute Leukemias

In the realm of hematologic disorders, acute leukemia is approached as an emergent disease given the multitude of complications and challenges that present both as a result of inherent disease pathology and adverse events associated with antineoplastic therapies and interventions. The heavy burden of leukemic cells may lead to complications including tumor lysis syndrome, hyperleukocytosis, leukostasis, and differentiation syndrome, and the initiation of treatment can further exacerbate these effects. Capillary leak syndrome is observed as a result of antineoplastic agents used in acute leukemia, and L-asparaginase, a bacterial-derived enzyme, has a unique side effect profile including association with thrombosis. Thrombohemorrhagic syndrome and malignancy-associated thrombosis are also commonly observed complications due to direct disequilibrium in coagulant and anticoagulant factors. Due to inherent effects on the white blood cell milieu, leukemia patients are inherently immunocompromised and vulnerable to life-threatening sepsis. Lastly, the advents of newer therapies such as chimeric antigen receptor (CAR) T-cells have clinicians facing the management of related toxicities on unfamiliar territory. This review aims to discuss these acute leukemia-associated complications, their pathology, and management recommendations.

How I manage acute respiratory failure in patients with hematological malignancies

ABSTRACT

Acute respiratory failure (ARF) is common in patients with hematological malignancies notably those with acute leukemia, myelodysplastic syndrome, or allogeneic stem cell transplantation. ARF is the leading reason for intensive care unit (ICU) admission, with a 35% case fatality rate. Failure to identify the ARF cause is associated with mortality. A prompt, well-designed diagnostic workup is crucial. The investigations are chosen according to pretest diagnostic probabilities, estimated by the DIRECT approach: D stands for delay, or time since diagnosis; I for pattern of immune deficiency; R and T for radiological evaluation; E refers to clinical experience, and C to the clinical picture. Thorough familiarity with rapid diagnostic tests helps to decrease the use of bronchoscopy with bronchoalveolar lavage, which can cause respiratory status deterioration in those patients with hypoxemia. A prompt etiological diagnosis shortens the time on unnecessary empirical treatments, decreasing iatrogenic harm and costs. High-quality collaboration between intensivists and hematologists and all crossdisciplinary health care workers is paramount. All oxygen delivery systems should be considered to minimize invasive mechanical ventilation. Treatment of the malignancy is started or continued in the ICU under the guidance of the hematologists. The goal is to use the ICU as a bridge to recovery, with the patient returning to the hematology ward in sufficiently good clinical condition to receive optimal anticancer treatment.

Kidney and Urinary Tract Involvement in Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy affecting the bone marrow and resulting in peripheral blood monocytosis. Kidney and urinary tract involvement is common and can present dramatically with life-threatening consequences. Kidney involvement can be the result of direct or indirect mechanisms, including prerenal azotemia, glomerular disease, tubulointerstitial involvement, and renovascular disorders. Urinary tract involvement, electrolyte and acid-base disorders, as well as nephrotoxicity from treatment of the disorder can also occur. Given this multifactorial pathogenesis involving several mechanisms concomitantly, nephrologists must exercise heightened awareness and maintain a low threshold for kidney biopsy. There is a pressing need for future research endeavors to elucidate and target the manifestations of CMML that involve the kidneys with the ultimate goal of augmenting overall prognosis and therapeutic outcomes.

Targeting integrins in drug-resistant acute myeloid leukaemia

Acute myeloid leukaemia (AML) continues to have a poor prognosis, warranting new therapeutic strategies. The bone marrow (BM) microenvironment consists of niches that interact with not only normal haematopoietic stem cells (HSC) but also leukaemia cells like AML. There are many adhesion molecules in the BM microenvironment; therein, integrins have been of central interest. AML cells express integrins that bind to ligands in the microenvironment, enabling adhesion of leukaemia cells in the microenvironment, thereby initiating intracellular signalling pathways that are associated with cell migration, cell proliferation, survival, and drug resistance that has been described to mediate cell adhesion-mediated drug resistance (CAM-DR). Identifying and targeting integrins in AML to interrupt interactions with the microenvironment have been pursued as a strategy to overcome CAM-DR. Here, we focus on the BM microenvironment and review the role of integrins in CAM-DR of AML and discuss integrin-targeting strategies. LINKED ARTICLES: This article is part of a themed issue on Cancer Microenvironment and Pharmacological Interventions. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.2/issuetoc.

The role of bone marrow microenvironment (BMM) cells in acute myeloid leukemia (AML) progression: immune checkpoints, metabolic checkpoints, and signaling pathways

Acute myeloid leukemia (AML) comprises a multifarious and heterogeneous array of illnesses characterized by the anomalous proliferation of myeloid cells in the bone marrow microenvironment (BMM). The BMM plays a pivotal role in promoting AML progression, angiogenesis, and metastasis. The immune checkpoints (ICs) and metabolic processes are the key players in this process. In this review, we delineate the metabolic and immune checkpoint characteristics of the AML BMM, with a focus on the roles of BMM cells e.g. tumor-associated macrophages, natural killer cells, dendritic cells, metabolic profiles and related signaling pathways. We also discuss the signaling pathways stimulated in AML cells by BMM factors that lead to AML progression. We then delve into the roles of immune checkpoints in AML angiogenesis, metastasis, and cell proliferation, including co-stimulatory and inhibitory ICs. Lastly, we discuss the potential therapeutic approaches and future directions for AML treatment, emphasizing the potential of targeting metabolic and immune checkpoints in AML BMM as prognostic and therapeutic targets. In conclusion, the modulation of these processes through the use of directed drugs opens up new promising avenues in combating AML. Thereby, a comprehensive elucidation of the significance of these AML BMM cells' metabolic and immune checkpoints and signaling pathways on leukemic cells can be undertaken in the future investigations. Additionally, these checkpoints and cells should be considered plausible multi-targeted therapies for AML in combination with other conventional treatments in AML. Video Abstract.

Insights Regarding the Role of Inflammasomes in Leukemia: What Do We Know?

Inflammation is a physiological mechanism of the immune response and has an important role in maintaining the hematopoietic cell niche in the bone marrow. During this process, the participation of molecules produced by innate immunity cells in response to a variety of pathogen-associated molecular patterns and damage-associated molecular patterns is observed. However, chronic inflammation is intrinsically associated with leukemogenesis, as it induces DNA damage in hematopoietic stem cells and contributes to the creation of the preleukemic clone. Several factors influence the malignant transformation within the hematopoietic microenvironment, with inflammasomes having a crucial role in this process, in addition to acting in the regulation of hematopoiesis and its homeostasis. Inflammasomes are intracellular multimeric complexes responsible for the maturation and secretion of the proinflammatory cytokines interleukin-1β and interleukin-18 and the cell death process via pyroptosis. Therefore, dysregulation of the activation of these complexes may be a factor in triggering several diseases, including leukemias, and this has been the subject of several studies in the area. In this review, we summarized the current knowledge on the relationship between inflammation and leukemogenesis, in particular, the role of inflammasomes in different types of leukemias, and we describe the potential therapeutic targets directed at inflammasomes in the leukemic context.

Leukostasis With Isolated Central Nervous System Involvement in Chronic Phase of Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (CML) is a hematologic malignancy with unique significance to the field of hematology and oncology, specifically due to the development of tyrosine kinase inhibitors (TKIs). CML often presents with nonspecific symptoms, and the quality of life in patients with CML has drastically improved as a result of TKIs. However, complications of CML including the risk of transforming into life-threatening blast crises continue to exist. Further, as most patients are asymptomatic in the chronic phase, patients often present with serious complications associated with noncompliance to TKIs. For example, central nervous system (CNS) manifestations of CML have been reported, both as the initial presentation of undiagnosed CML and as known complication of uncontrolled CML. Hyperleukocytosis is a manifestation of uncontrolled CML and leukostasis is a complication, occurring in cases of acute myeloid leukemia (AML). Here we present a rare case of leukostasis in a patient with known CML presenting on computed tomography (CT) as intracranial masses in the chronic phase. Our goal is to discuss this rare case of leukostasis in adult CML and describe its management.

Role of the bone marrow vascular niche in chemotherapy for MLL-AF9-induced acute myeloid leukemia

Leukemia stem cells in acute myeloid leukemia (AML) can persist within unique bone marrow niches similar to those of healthy hematopoietic stem cells and resist chemotherapy. In the context of AML, endothelial cells (ECs) are crucial components of these niches that appear to promote malignant expansion despite treatment. To better understand these interactions, we developed a real-time cell cycle-tracking mouse model of AML (Fucci-MA9) with an aim of unraveling why quiescent leukemia cells are more resistant to chemotherapy than cycling cells and proliferate during disease relapse. We found that quiescent leukemia cells were more prone to escape chemotherapy than cycling cells, leading to relapse and proliferation. Importantly, post-chemotherapy resting leukemia cells tended to localize closer to blood vessels. Mechanistically, after chemotherapy, resting leukemia cells interacted with ECs, promoting their adhesion and anti-apoptotic capacity. Further, expression analysis of ECs and leukemia cells during AML, after chemotherapy, and after relapse revealed the potential of suppressing the post-chemotherapy inflammatory response to regulate the functions of leukemia cells and ECs. These findings highlight the role of leukemia cells in evading chemotherapy by seeking refuge near blood vessels and provide important insights and directions for future AML research and treatment.

Early-onset venous thromboembolisms in newly diagnosed non-promyelocytic acute myeloid leukemia patients undergoing intensive induction chemotherapy

OBJECTIVES AND METHODS

Venous thromboembolic (VTE) events are emerging as frequent complications in acute myeloid leukemia (AML); however, there is insufficient data regarding epidemiology, risk factors, and impact on outcomes. The optimal approach to balance risks of thrombosis and hemorrhage remains unclear. This retrospective single-center study in AML patients undergoing induction chemotherapy between 2007 and 2018 assessed incidence, risk factors, features, and outcomes of early-onset VTE.

RESULTS

423 patients (median age 59 years) were enrolled. VTE was diagnosed in 31 patients (7.3%) within 3 months of admission. The median time to VTE was 3 days. Non-central venous catheter (CVC)-related VTE occurred in 19 patients (61%). Main risk factor for VTE was leukocytosis at admission, independent of platelet counts/INR. Four patients (13%) exhibited VTE recurrence. No deaths directly related to VTE or major bleeding events associated with platelet-adjusted anticoagulation in patients with VTE were recorded. There was no clear impact of VTE on 1-year overall survival; however, non-CVC-related VTE may be associated with adverse outcomes.

CONCLUSIONS

Early-onset VTE is a common complication in newly diagnosed AML patients admitted for induction chemotherapy. Leukocytosis is an independent VTE risk factor. The potentially adverse impact of non-CVC-related VTE merits further study.

Present and Future Role of Immune Targets in Acute Myeloid Leukemia

It is now well known that the bone marrow (BM) cell niche contributes to leukemogenesis, but emerging data support the role of the complex crosstalk between AML cells and the BM microenvironment to induce a permissive immune setting that protects leukemic stem cells (LSCs) from therapy-induced death, thus favoring disease persistence and eventual relapse. The identification of potential immune targets on AML cells and the modulation of the BM environment could lead to enhanced anti-leukemic effects of drugs, immune system reactivation, and the restoration of AML surveillance. Potential targets and effectors of this immune-based therapy could be monoclonal antibodies directed against LSC antigens such as CD33, CD123, and CLL-1 (either as direct targets or via several bispecific T-cell engagers), immune checkpoint inhibitors acting on different co-inhibitory axes (alone or in combination with conventional AML drugs), and novel cellular therapies such as chimeric antigen receptor (CAR) T-cells designed against AML-specific antigens. Though dozens of clinical trials, mostly in phases I and II, are ongoing worldwide, results have still been negatively affected by difficulties in the identification of the optimal targets on LSCs.

Molecular profiling of patients with cytogenetically normal acute myeloid leukemia and hyperleukocytosis

BACKGROUND

Acute myeloid leukemia (AML) with initial hyperleukocytosis is associated with high early mortality and a poor prognosis. The aims of this study were to delineate the underlying molecular landscape in the largest cytogenetic risk group, cytogenetically normal acute myeloid leukemia (CN-AML), and to assess the prognostic relevance of recurrent mutations in the context of hyperleukocytosis and clinical risk factors.

METHODS

The authors performed a targeted sequencing of 49 recurrently mutated genes in 56 patients with newly diagnosed CN-AML and initial hyperleukocytosis of ≥100 G/L treated in the AMLCG99 study. The median number of mutated genes per patient was 5. The most common mutations occurred in FLT3 (73%), NPM1 (75%), and TET2 (45%).

RESULTS

The predominant pathways affected by mutations were signaling (84% of patients), epigenetic modifiers (75% of patients), and nuclear transport (NPM1; 75%) of patients. AML with hyperleukocytosis was enriched for molecular subtypes that negatively affected the prognosis, including a high percentage of patients presenting with co-occurring mutations in signaling and epigenetic modifiers such as FLT3 internal tandem duplications and TET2 mutations.

CONCLUSIONS

Despite these unique molecular features, clinical risk factors, including high white blood count, hemoglobin level, and lactate dehydrogenase level at baseline, remained the predictors for overall survival and relapse-free survival in hyperleukocytotic CN-AML.

The Increase in the Drug Resistance of Acute Myeloid Leukemia THP-1 Cells in High-Density Cell Culture Is Associated with Inflammatory-like Activation and Anti-Apoptotic Bcl-2 Proteins

It is known that cell culture density can modulate the drug resistance of acute myeloid leukemia (AML) cells. In this work, we studied the drug sensitivity of AML cells in high-density cell cultures (cell lines THP-1, HL-60, MV4-11, and U937). It was shown that the AML cells in high-density cell cultures in vitro were significantly more resistant to DNA-damaging drugs and recombinant ligand izTRAIL than those in low-density cell cultures. To elucidate the mechanism of the increased drug resistance of AML cells in high-density cell cultures, we studied the activation of Bcl-2, Hif-1alpha, and NF-kB proteins, as well as cytokine secretion, the inflammatory immunophenotype, and the transcriptome for THP-1 cells in the low-density and high-density cultures. The results indicated that the increase in the drug resistance of proliferating THP-1 cells in high-density cell cultures was associated with the accumulation of inflammatory cytokines in extracellular medium, and the formation of NF-kB-dependent inflammatory-like cell activation with the anti-apoptotic proteins Bcl-2 and Bcl-xl. The increased drug resistance of THP-1 cells in high-density cultures can be reduced by ABT-737, an inhibitor of Bcl-2 family proteins, and by inhibitors of NF-kB. The results suggest a mechanism for increasing the drug resistance of AML cells in the bone marrow and are of interest for developing a strategy to suppress this resistance.

Brusatol Inhibits Proliferation and Metastasis of Colorectal Cancer by Targeting and Reversing the RhoA/ROCK1 Pathway

Brusatol (BRU) is an important compound extracted from Brucea javanica oil, whose pharmacological effects are able to induce a series of biological effects, including inhibition of tumor cell growth, anti-inflammatory, antiviral, and antitumor. Currently, there are so few studies about the brusatol effects on colorectal cancer that its anticancer mechanism has not been clearly defined. In this study, we made an in-depth investigation into the brusatol effect towards the proliferation and metastasis of colon cancer and the possible mechanism. The inhibitory effect of BRU on the proliferation of colorectal cancer cells was unveiled via CCK-8 method and colony formation assay, while the inhibitory effect of BRU on migration and invasion of colorectal cancer cells was revealed by scratch assay and transwell assay. In addition, Western blot results also revealed that BRU inhibited not only the expressions of RhoA and ROCK1 but also the protein expressions of EMT-related markers e-cadherin, N-cadherin, Vimentin, MMP2, and MMP9 in colon cancer cells. Through the xenotransplantation model, our in vivo experiment further verified the antitumor effect of BRU on colon cancer cells in vitro, and the results were consistent with the protein expression trend. In conclusion, BRU may inhibit the proliferation and metastasis of colorectal cancer by influencing EMT through RhoA/ROCK1 pathway.

Characteristics of Sweet syndrome in patients with or without malignancy

Sweet syndrome is a neutrophilic dermatosis occasionally associated with malignancies. Due to its rarity, the clinical features of Sweet syndrome are still unclear. Thus, we aimed to analyze clinical features, treatment, and outcomes of these patients according to associated disease. We conducted a retrospective, longitudinal cohort study from January 2000 to August 2020. We reviewed the medical records of 52 patients with Sweet syndrome. The median age of patients was 57.5 years old (range, 17-84), and 48.1% were female. Of the 52 patients analyzed, 27 patients (51.9%) had malignancy-associated Sweet syndrome. Sweet syndrome was diagnosed concurrently with (N = 8), before (N = 5), and after (N = 14) the diagnosis of malignancy. The idiopathic Sweet syndrome was most common in the non-malignancy group (56.0%). Myelodysplastic syndrome was the most common malignancy associated with Sweet syndrome (47.6%). Leukopenia (p = 0.005), anemia (p < 0.001), and thrombocytopenia (p = 0.008) were significantly associated with malignancy. The majority of patients showed rapid improvement of symptoms after steroid administration. The symptoms of some patients with malignancy did not improve with steroid alone; however, their symptoms often improved when steroids were combined with a treatment for the associated malignancy. Relapse and aggravation of Sweet syndrome were common in the malignancy group. Sweet syndrome showed a broad spectrum of clinical features related to various diseases. Sweet syndrome often occurred as a paraneoplastic feature. Therefore, active systemic evaluation is needed in the first diagnosis of Sweet syndrome without clear etiology.

Management of Hyperleukocytosis in Childhood Acute Leukemia Without Leukapheresis and Rasburicase Prophylaxis

Indications of leukapheresis (LPh) and the prophylactic use of rasburicase in tumor lysis syndrome (TLS) of patients with acute leukemia with hyperleukocytosis are not clear. In this retrospective single-center pediatric study, the outcomes of patients with hyperleukocytosis were reviewed. There were 48 patients with acute lymphoblastic leukemia (ALL) and 13 patients with acute myeloblastic leukemia (AML). The treatment strategies included hyperhydration, allopurinol administration, strict monitoring, and early initiation of induction chemotherapy (CT). No patient underwent LPh because it was not available. Rasburicase was used only in 3 ALL patients with hyperuricemia when the drug was available. Laboratory and clinical TLS developed in 54.16% and 14.58% of patients with ALL, respectively. Laboratory and clinical TLS developed in 76.92% and 15.38% of patients with AML, respectively. No patient developed grade III to V TLS requiring dialysis. Thirteen patients (21.3%) had pulmonary leukostasis on admission, but recovered with CT and nasal oxygen. During the first 14 days of presentation, cerebral leukostasis/coagulopathy-related early death (ED) was 4.2% and 7.7% in patients with ALL and AML, respectively, and all of these patients had a white blood cell count ≥400,000/µL. There was also 1 infection-related death. Patients with hyperleukocytosis can be treated without LPh and liberal use of rasburicase. Renal failure is no longer a cause of ED. Intracranial hemorrhage is the main cause of ED, especially in patients already presenting with this complication. LPh may be performed in patients with leukostasis, if it is not possible to start induction CT early. When resources are limited, rasburicase should be administered in patients presenting with or developing hyperuricemia and/or renal dysfunction.

The Bone Marrow Microenvironment Mechanisms in Acute Myeloid Leukemia

Bone marrow (BM) is a highly complex tissue that provides important regulatory signals to orchestrate hematopoiesis. Resident and transient cells occupy and interact with some well characterized niches to produce molecular and cellular mechanisms that interfere with differentiation, migration, survival, and proliferation in this microenvironment. The acute myeloid leukemia (AML), the most common and severe hematological neoplasm in adults, arises and develop in the BM. The osteoblastic, vascular, and reticular niches provide surface co-receptors, soluble factors, cytokines, and chemokines that mediate important functions on hematopoietic cells and leukemic blasts. There are some evidences of how AML modify the architecture and function of these three BM niches, but it has been still unclear how essential those modifications are to maintain AML development. Basic studies and clinical trials have been suggesting that disturbing specific cells and molecules into the BM niches might be able to impair leukemia competencies. Either through niche-specific molecule inhibition alone or in combination with more traditional drugs, the bone marrow microenvironment is currently considered the potential target for new strategies to treat AML patients. This review describes the cellular and molecular constitution of the BM niches under healthy and AML conditions, presenting this anatomical compartment by a new perspective: as a prospective target for current and next generation therapies.

Acute leukemia presenting as acute lower limb ischemia

Objectives: Acute lower limb ischemia (ALLI) is a common vascular emergency. However, ALLI presenting as the initial symptom of acute leukemia (AL) is scarce. Here we present a case of ALLI in the setting of acute myeloid leukemia (AML) while systematically reviewing the current literature to withdraw conclusions about the management, prognosis, and treatment for this atypical presentation of AL. Methods: We conducted a systematic electronic research according to Preferred Reporting Items for Systematic Review and Meta-Analysis protocol (PRISMA) for articles published from January 1981 up to January 2021 concerning ALLI in the setting of acute leukemia (AL). Patients' baseline characteristics were recorded and nine outcomes of interest were studied. Results: Twenty-six individuals, 16 males with a mean age of 46.3 years (±20) were included in this review. The diagnosis included 13 AML patients (50%), 11 acute promyelotic leukemia (APL) (42.3%) and two acute lymphoblastic leukemias (ALL) (7.7%). Treatment varied among nine different regimens. Four patients were treated with chemotherapy alone (15.4%), four with thrombectomy alone (15.4%), and 11 with a combination of chemotherapy and thrombectomy (42.3%). Eight major amputations were recorded (30. 8%). Thirty-day mortality was 35.7%. Forty-eight peripheral thrombotic events were recorded with 12 patients suffering recurrent thrombotic events. Conclusion: ALLI as the presenting symptom of AL is a rare condition that carries significant mortality and amputation rates. Timely diagnosis is crucial concerning short-term survival and limb salvage. APL, despite being the rarest form of AL, represented a significant proportion of the patient population in this review. The role of leukostasis in the disease's progression and the efficacy of leukapheresis as a treatment regimen should be further investigated through case-control studies.

Stability and Safety of Inhibitor Cystine Knot Peptide, GTx1-15, from the Tarantula Spider Grammostola rosea

Inhibitor cystine knot (ICK) peptides are knotted peptides with three intramolecular disulfide bonds that affect several types of ion channels. Some are proteolytically stable and are promising scaffolds for drug development. GTx1-15 is an ICK peptide that inhibits the voltage-dependent calcium channel Ca_v3.1 and the voltage-dependent sodium channels Na_v1.3 and Na_v1.7. As a model molecule to develop an ICK peptide drug, we investigated several important pharmaceutical characteristics of GTx1-15. The stability of GTx1-15 in rat and human blood plasma was examined, and no GTx1-15 degradation was observed in either rat or human blood plasma for 24 h in vitro. GTx1-15 in blood circulation was detected for several hours after intravenous and intramuscular administration, indicating high stability in plasma. The thermal stability of GTx1-15 as examined by high thermal incubation and protein thermal shift assays indicated that GTx1-15 possesses high heat stability. The cytotoxicity and immunogenicity of GTx1-15 were examined using the human monocytic leukemia cell line THP-1. GTx1-15 showed no cytotoxicity or immunogenicity even at high concentrations. These results indicate that GTx1-15 itself is suitable for peptide drug development and as a peptide library scaffold.

Sudden death due to leukostasis in a subject with undiagnosed chronic lymphocytic leukemia

Sudden death due to leukostasis and lymphocyte thrombi in patients with chronic hematologic malignancies is rare. Leukostasis is characterized by highly elevated leukemic cell count and decreased tissue perfusion symptoms, leading to severe complications and even death. Chronic lymphocytic leukemia (CLL) is a chronic lymphoproliferative disorder that shows a highly heterogeneous clinical course, ranging from indolent form to very aggressive disease. Due to its low metabolic and mitotic rate, there is a lower incidence of clinically significant leukostasis in patients with CLL. Two main theories have been proposed in the development of leukostasis: (1) increased blood viscosity due to large leukemic cell populations; (2) high metabolic activity and cytokine production by leukemic cells. Both mechanisms lead to local hypoxic damage.We present a case of a 70-year-old man who died suddenly in the absence of symptoms. Autopsy and histology examinations revealed findings consistent with CLL and diffuse leukostasis involving the major organs' vessels.In the presence of gross and/or microscopic findings suggesting a potential hematologic malignancy, undiagnosed or relapsing hematologic malignancies should be considered in the differential diagnosis of sudden deaths.

Intracranial Hemorrhage Associated With T-Cell Acute Lymphoblastic Leukemia With Hyperleukocytosis: A Case Report

Acute leukemia in children may present with hyperleukocytosis. Symptomatic hyperleukocytosis is a medical emergency that necessitates rapid stabilization of the patient and prompt lowering of the leukocyte count. We report on a patient with intracranial hemorrhage associated with T-cell acute lymphoblastic leukemia with hyperleukocytosis, which is a rare occurrence. A 16-year-old boy with hyperleukocytosis (total white cell count; 398×103/µL) underwent repeated leukapheresis and received supportive treatment until a definite diagnosis of T-cell acute lymphoblastic leukemia was made and chemotherapy was started at 10% of the usual dose. On day 2 of treatment, he had headache, vomiting, and was agitated. Brain magnetic resonance imaging showed bilateral extensive hemispheric and cerebellar punctate areas of hemorrhage and perilesional edema. Chemotherapy intensified to a maximum dose on day 3. If supportive care for tumor lysis syndrome can be promptly provided, initial chemotherapy regimen can immediately be begun at an optimal dose.

Fluid overload is associated with increased 90-day mortality in AML patients undergoing induction chemotherapy

Treatment‐related complications contribute substantially to morbidity and mortality in acute myeloid leukemia (AML) patients undergoing induction chemotherapy. Although AML patients are susceptible to fluid overload (FO) (e.g., in the context of chemotherapy protocols, during sepsis treatment or to prevent tumor lysis syndrome), little attention has been paid to its role in AML patients undergoing induction chemotherapy. AML patients receiving induction chemotherapy between 2014 and 2019 were included in this study. FO was defined as ≥5% weight gain on day 7 of induction chemotherapy compared to baseline weight determined on the day of admission. We found FO in 23 (12%) of 187 AML patients undergoing induction chemotherapy. Application of >100 ml crystalloid fluids/kg body weight until day 7 of induction chemotherapy was identified as an independent risk factor for FO. AML patients with FO suffered from a significantly increased 90-day mortality rate and FO was demonstrated as an independent risk factor for 90-day mortality. Our data suggests an individualized, weight-adjusted calculation of crystalloid fluids in order to prevent FO-related morbidity and mortality in AML patients during induction chemotherapy. Prospective trials are required to determine the adequate fluid management in this patient population.

Leukapheresis Does Not Improve Early Survival Outcome of Acute Myeloid Leukemia with Leukostasis Patients - A Dual-Center Retrospective Cohort Study

Introduction

Leukostasis is a medical emergency with high mortality which often occurs in acute myeloid leukemia patients with hyperleukocytosis. One of the therapies that can be used for leukostasis in acute myeloid leukemia is leukapheresis. However, whether leukapheresis can provide better survival benefit when compared with patients not receiving leukapheresis is still unclear. Hence, we aimed to evaluate the effect of chemotherapy plus leukapheresis combination versus chemotherapy only on 28-day survival of acute myeloid leukemia patients with leukostasis.

Methods

This study was a dual-center retrospective cohort using secondary data from medical records collected from November 2018 to March 2019. Inclusion criteria were adult patients aged 18 years old or above, diagnosed with acute leukemia with hyperleukocytosis status defined by WBC count greater than 100,000/uL, and with symptoms of leukostasis. One-month survival analysis was conducted using Kaplan–Meier curve method. Univariate and multivariate analyses were then conducted using Cox proportional hazards model to obtain value of hazard ratio (HR) with a 95% confidence interval (CI).

Results

A total of 38 patients were obtained for analysis. The median overall survival was 25 days (95% CI: 17.001–32.999 days) in the chemotherapy only group and 20 days (95% CI: 1.497–38.503) in the chemotherapy with leukapheresis group. The use of leukapheresis did not affect 28-day survival (HR: 1.140; 95% CI: 0.396–3.283; p value: 0.809) and 7-day survival (HR: 1.073; 95% CI: 0.277–4.152; p value: 0.919). In the multivariate analysis, age ≥60 years, blast percentage ≥90%, creatinine ≥1.4 mg/dL, and presence of disseminated intravascular coagulation were associated with worse 28-day survival.

Conclusion

AML patients with leukostasis who received both chemotherapy and leukapheresis did not have better 28-day survival and 7-day survival when compared with patients receiving chemotherapy only. Old age, high blast percentage, high creatinine, and presence of disseminated intravascular coagulation were prognostic factors for worse 28-day survival.

Ophthalmologic manifestations as the initial presentation of chronic myeloid leukemia: A review

The presentation of chronic myeloid leukemia (CML) can be variable and related to the phase of the disease. It can manifest a wide range of symptoms and signs; ocular involvement is reported in patients with leukemia at the time of diagnosis. We describe ophthalmic manifestations as an initial presentation in patients with CML. We identified 38 publications between 1971 and 2020 describing ocular manifestations in CML. Ophthalmic problems occur either from direct or indirect infiltration of neoplastic cells or from secondary causes. Although nearly all ocular structures may be affected, leukemic retinopathy is the most frequent clinical manifestation. Others include iris infiltration, anterior uveitis, hypopyon, exudative/serous retinal detachment, and optic nerve infiltration.

Leukaemia: a model metastatic disease

In contrast to solid cancers, which often require genetic modifications and complex cellular reprogramming for effective metastatic dissemination, leukaemic cells uniquely possess the innate ability for migration and invasion. Dedifferentiated, malignant leukocytes retain the benign leukocytes' capacity for cell motility and survival in the circulation, while acquiring the potential for rapid and uncontrolled cell division. For these reasons, leukaemias, although not traditionally considered as metastatic diseases, are in fact models of highly efficient metastatic spread. Accordingly, they are often aggressive and challenging diseases to treat. In this Perspective, we discuss the key molecular processes that facilitate metastasis in a variety of leukaemic subtypes, the clinical significance of leukaemic invasion into specific tissues and the current pipeline of treatments targeting leukaemia metastasis.

Optimizing NK Cell-Based Immunotherapy in Myeloid Leukemia: Abrogating an Immunosuppressive Microenvironment

Natural killer (NK) cells are prominent cytotoxic and cytokine-producing components of the innate immune system representing crucial effector cells in cancer immunotherapy. Presently, various NK cell-based immunotherapies have contributed to the substantial improvement in the reconstitution of NK cells against advanced-staged and high-risk AML. Various NK cell sources, including haploidentical NK cells, adaptive NK cells, umbilical cord blood NK cells, stem cell-derived NK cells, chimeric antigen receptor NK cells, cytokine-induced memory-like NK cells, and NK cell lines have been identified. Devising innovative approaches to improve the generation of therapeutic NK cells from the aforementioned sources is likely to enhance NK cell expansion and activation, stimulate ex vivo and in vivo persistence of NK cells and improve conventional treatment response of myeloid leukemia. The tumor-promoting properties of the tumor microenvironment and downmodulation of NK cellular metabolic activity in solid tumors and hematological malignancies constitute a significant impediment in enhancing the anti-tumor effects of NK cells. In this review, we discuss the current NK cell sources, highlight ongoing interventions in enhancing NK cell function, and outline novel strategies to circumvent immunosuppressive factors in the tumor microenvironment to improve the efficacy of NK cell-based immunotherapy and expand their future success in treating myeloid leukemia.

Acute Myeloid Leukemia Complicated by Hyperleukocytosis and Leukostasis in the Emergency Department

Acute myeloid leukemia (AML) and other hematologic malignancies can be complicated by hyperleukocytosis, which leads to an increased risk for other severe complications such as tumor lysis syndrome, disseminated intravascular coagulation (DIC), and leukostasis. In this report, we present a case of a 65-year-old female with newly diagnosed AML complicated by leukostasis. We briefly review the clinical significance as well as initial diagnostic and therapeutic considerations pertaining to hyperleukocytosis and its associated complications.

Biophysical interactions between components of the tumor microenvironment promote metastasis

During metastasis, tumor cells need to adapt to their dynamic microenvironment and modify their mechanical properties in response to both chemical and mechanical stimulation. Physical interactions occur between cancer cells and the surrounding matrix including cell movements and cell shape alterations through the process of mechanotransduction. The latter describes the translation of external mechanical cues into intracellular biochemical signaling. Reorganization of both the cytoskeleton and the extracellular matrix (ECM) plays a critical role in these spreading steps. Migrating tumor cells show increased motility in order to cross the tumor microenvironment, migrate through ECM and reach the bloodstream to the metastatic site. There are specific factors affecting these processes, as well as the survival of circulating tumor cells (CTC) in the blood flow until they finally invade the secondary tissue to form metastasis. This review aims to study the mechanisms of metastasis from a biomechanical perspective and investigate cell migration, with a focus on the alterations in the cytoskeleton through this journey and the effect of biologic fluids on metastasis. Understanding of the biophysical mechanisms that promote tumor metastasis may contribute successful therapeutic approaches in the fight against cancer.

Effect of prophylactic leukapheresis on early mortality and overall survival in acute leukemia patients with hyperleukocytosis

Hyperleukocytosis has been associated with early mortality owing to the presence of complications including leukostasis, tumor lysis syndrome (TLS), and disseminated intravascular coagulation (DIC). Leukapheresis is a fast and effective cytoreductive procedure that removes leukocytes from the peripheral circulation. This single-center, retrospective, and observational study included 32 patients diagnosed with acute leukemia who underwent leukapheresis due to hyperleukocytosis between 2014 and 2020. This study primarily aimed to investigate the effect of prophylactic leukapheresis on early mortality and overall survival (OS). In the symptomatic group, seven and two patients died in the first and second weeks, respectively. In the prophylactic leukapheresis group, two and one patients died in the first and second weeks (p = 0.792), respectively. OS was significantly longer in the prophylactic leukapheresis group (p = 0.004). The leukapheresis procedure appears to be effective on early mortality and OS. Initiation of prophylactic leukapheresis before the appearance of leukostasis symptoms is effective on OS and possibly early mortality.

The Dynamic Interface Between the Bone Marrow Vascular Niche and Hematopoietic Stem Cells in Myeloid Malignancy

Hematopoietic stem cells interact with bone marrow niches, including highly specialized blood vessels. Recent studies have revealed the phenotypic and functional heterogeneity of bone marrow endothelial cells. This has facilitated the analysis of the vascular microenvironment in steady state and malignant hematopoiesis. In this review, we provide an overview of the bone marrow microenvironment, focusing on refined analyses of the marrow vascular compartment performed in mouse studies. We also discuss the emerging role of the vascular niche in “inflamm-aging” and clonal hematopoiesis, and how the endothelial microenvironment influences, supports and interacts with hematopoietic cells in acute myeloid leukemia and myelodysplastic syndromes, as exemplar states of malignant myelopoiesis. Finally, we provide an overview of strategies for modulating these bidirectional interactions to therapeutic effect in myeloid malignancies.

Clinical Implications of Inflammation in Acute Myeloid Leukemia

Recent advances in the description of the tumor microenvironment of acute myeloid leukemia, including the comprehensive analysis of the leukemic stem cell niche and clonal evolution, indicate that inflammation may play a major role in many aspects of acute myeloid leukemia (AML) such as disease progression, chemoresistance, and myelosuppression. Studies on the mechanisms of resistance to chemotherapy or tyrosine kinase inhibitors along with high-throughput drug screening have underpinned the potential role of glucocorticoids in this disease classically described as steroid-resistant in contrast to acute lymphoblastic leukemia. Moreover, some mutated oncogenes such as RUNX1, NPM1, or SRSF2 transcriptionally modulate cell state in a manner that primes leukemic cells for glucocorticoid sensitivity. In clinical practice, inflammatory markers such as serum ferritin or IL-6 have a strong prognostic impact and may directly affect disease progression, whereas interesting preliminary data suggested that dexamethasone may improve the outcome for AML patients with a high white blood cell count, which paves the way to develop prospective clinical trials that evaluate the role of glucocorticoids in AML.

Pulmonary Manifestations of Hematologic and Oncologic Diseases in Children

Pulmonary complications are common in children with hematologic or oncologic diseases, and many experience long-term effects even after the primary disease has been cured. This article reviews pulmonary complications in children with cancer, after hematopoietic stem cell transplant, and caused by sickle cell disease and discusses their management.

A narrative review of central nervous system involvement in acute leukemias

Acute leukemias (both myeloid and lymphoblastic) are a group of diseases for which each year more successful therapies are implemented. However, in a subset of cases the overall survival (OS) is still exceptionally low due to the infiltration of leukemic cells in the central nervous system (CNS) and the subsequent formation of brain tumors. The CNS involvement is more common in acute lymphocytic leukemia (ALL), than in adult acute myeloid leukemia (AML), although the rates for the second case might be underestimated. The main reasons for CNS invasion are related to the expression of specific adhesion molecules (VLA-4, ICAM-1, VCAM, L-selectin, PECAM-1, CD18, LFA-1, CD58, CD44, CXCL12) by a subpopulation of leukemic cells, called “sticky cells” which have the ability to interact and adhere to endothelial cells. Moreover, the microenvironment becomes hypoxic and together with secretion of VEGF-A by ALL or AML cells the permeability of vasculature in the bone marrow increases, coupled with the disruption of blood brain barrier. There is a single subpopulation of leukemia cells, called leukemia stem cells (LSCs) that is able to resist in the new microenvironment due to its high adaptability. The LCSs enter into the arachnoid, migrate, and intensively proliferate in cerebrospinal fluid (CSF) and consequently infiltrate perivascular spaces and brain parenchyma. Moreover, the CNS is an immune privileged site that also protects leukemic cells from chemotherapy. CD56/NCAM is the most important surface molecule often overexpressed by leukemic stem cells that offers them the ability to infiltrate in the CNS. Although asymptomatic or with unspecific symptoms, CNS leukemia should be assessed in both AML/ALL patients, through a combination of flow cytometry and cytological analysis of CSF. Intrathecal therapy (ITT) is a preventive measure for CNS involvement in AML and ALL, still much research is needed in finding the appropriate target that would dramatically lower CNS involvement in acute leukemia.

Hyperleukocytosis and Leukostasis in Acute Myeloid Leukemia: Can a Better Understanding of the Underlying Molecular Pathophysiology Lead to Novel Treatments?

Up to 18% of patients with acute myeloid leukemia (AML) present with a white blood cell (WBC) count of greater than 100,000/µL, a condition that is frequently referred to as hyperleukocytosis. Hyperleukocytosis has been associated with an adverse prognosis and a higher incidence of life-threatening complications such as leukostasis, disseminated intravascular coagulation (DIC), and tumor lysis syndrome (TLS). The molecular processes underlying hyperleukocytosis have not been fully elucidated yet. However, the interactions between leukemic blasts and endothelial cells leading to leukostasis and DIC as well as the processes in the bone marrow microenvironment leading to the massive entry of leukemic blasts into the peripheral blood are becoming increasingly understood. Leukemic blasts interact with endothelial cells via cell adhesion molecules such as various members of the selectin family which are upregulated via inflammatory cytokines released by leukemic blasts. Besides their role in the development of leukostasis, cell adhesion molecules have also been implicated in leukemic stem cell survival and chemotherapy resistance and can be therapeutically targeted with specific inhibitors such as plerixafor or GMI-1271 (uproleselan). However, in the absence of approved targeted therapies supportive treatment with the uric acid lowering agents allopurinol and rasburicase as well as aggressive intravenous fluid hydration for the treatment and prophylaxis of TLS, transfusion of blood products for the management of DIC, and cytoreduction with intensive chemotherapy, leukapheresis, or hydroxyurea remain the mainstay of therapy for AML patients with hyperleukocytosis.

Reduce Mortality and Morbidity in Acute Myeloid Leukemia With Hyperleukocytosis With Early Admission in Intensive Care Unit: A Retrospective Analysis

Background

Patients presenting with acute myeloid leukemia (AML) at diagnosis are at high risk of severe complications and death, particularly with high white blood cell (WBC) count. In this retrospective study, we evaluate interest of early and systematic support in the intensive care unit (ICU) for AML with hyperleukocytosis (AML-HL) at diagnosis.

Methods

Patients with AML-HL, defined by WBC > 50 × 10⁹/L, primary referred in ICU (“Early ICU”) without organ failure and before initiating chemotherapy induction were compared to patients first admitted in the Hematology Department who required a secondary transfer in ICU (“Late ICU”) or not (“No ICU”). Primary end point was mortality during the first month, and secondary end points were the use of life-sustaining therapies in ICU and risk factors for ICU transfer and mortality.

Results

One hundred fifty-four patients were included: 77 (50%) to the group “No ICU”, 18 (12%) to “Late ICU” and 59 (38%) to “Early ICU”. Mortality at day 30 was higher in “Late ICU” than in “Early ICU” and “No ICU”, with 27.8%; 16.9% and 2.6% respectively (P < 0.001). “Late ICU” patients had an increased use of life-sustaining therapy comparing to “Early ICU” patients (56% vs. 29%, P = 0.04).

Conclusions

Early referral to ICU reduces morbidity and seems an effective strategy to reduce short-term mortality in AML-HL at diagnosis.

Endothelial damage and a thin intercellular fibrin network promote haemorrhage in acute promyelocytic leukaemia

Background

The role of vascular endothelium in acute promyelocytic leukaemia (APL) remains unknown. We aimed to investigate the mechanisms by which APL cells interact with endothelial cells (ECs) and to further explore how the endothelium affects bleeding as well as therapeutic interventions.

Method

APL cells and an original APL cell line, NB4 cells, were used for experiments. The effects of leukaemic cells on ECs were analyzed in vitro and in vivo. Moreover, the endothelial barrier function and procoagulant activity were detected. An APL mouse model was established for in vivo studies.

Findings

APL cells interacted with ECs via ICAM-1 and VCAM-1 receptors to disrupt endothelial integrity. This binding activated MLCK signaling, resulting in the trans-endothelial passage of protein and red blood cells (RBCs). Combined treatment with asiatic acid or anti-adhesion receptor antibody inhibited the response of ECs to APL cells, thereby preventing APL-associated haemorrhage in vitro and in vivo. Activated ECs exhibited a procoagulant phenotype after phosphatidylserine exposure. Plasma from APL patients formed a thin fibrin network between procoagulant ECs, and this intercellular fibrin decreased the passage of albumin and RBCs. Ex vivo addition of fibrinogen further enhanced this barrier function in a dose-dependent manner.

Interpretation

Endothelial damage induced by leukaemic cell adherence promotes haemorrhaging in APL. Stabilization of ECs, decreasing adhesion receptor expression, and increasing fibrinogen transfusion levels may be a new therapeutic avenue to alleviate this fatal bleeding complication.

Funding

National Science Foundation of China (81670128, 81873433).

STAT3β is a tumor suppressor in acute myeloid leukemia

Signal transducer and activator of transcription 3 (STAT3) exists in 2 alternatively spliced isoforms, STAT3α and STAT3β. Although truncated STAT3β was originally postulated to act as a dominant-negative form of STAT3α, it has been shown to have various STAT3α-independent regulatory functions. Recently, STAT3β gained attention as a powerful antitumorigenic molecule in cancer. Deregulated STAT3 signaling is often found in acute myeloid leukemia (AML); however, the role of STAT3β in AML remains elusive. Therefore, we analyzed the STAT3β/α messenger RNA (mRNA) expression ratio in AML patients, where we observed that a higher STAT3β/α mRNA ratio correlated with a favorable prognosis and increased overall survival. To gain better understanding of the function of STAT3β in AML, we engineered a transgenic mouse allowing for balanced Stat3β expression. Transgenic Stat3β expression resulted in decelerated disease progression and extended survival in PTEN- and MLL-AF9-dependent AML mouse models. Our findings further suggest that the antitumorigenic function of STAT3β depends on the tumor-intrinsic regulation of a small set of significantly up- and downregulated genes, identified via RNA sequencing. In conclusion, we demonstrate that STAT3β plays an essential tumor-suppressive role in AML.

Extracellular ATP and CD39 Activate cAMP-Mediated Mitochondrial Stress Response to Promote Cytarabine Resistance in Acute Myeloid Leukemia

Relapses driven by chemoresistant leukemic cell populations are the main cause of mortality for patients with acute myeloid leukemia (AML). Here, we show that the ectonucleotidase CD39 (ENTPD1) is upregulated in cytarabine-resistant leukemic cells from both AML cell lines and patient samples in vivo and in vitro. CD39 cell-surface expression and activity is increased in patients with AML upon chemotherapy compared with diagnosis, and enrichment in CD39-expressing blasts is a marker of adverse prognosis in the clinics. High CD39 activity promotes cytarabine resistance by enhancing mitochondrial activity and biogenesis through activation of a cAMP-mediated adaptive mitochondrial stress response. Finally, genetic and pharmacologic inhibition of CD39 ecto-ATPase activity blocks the mitochondrial reprogramming triggered by cytarabine treatment and markedly enhances its cytotoxicity in AML cells in vitro and in vivo. Together, these results reveal CD39 as a new residual disease marker and a promising therapeutic target to improve chemotherapy response in AML. SIGNIFICANCE: Extracellular ATP and CD39-P2RY13-cAMP-OxPHOS axis are key regulators of cytarabine resistance, offering a new promising therapeutic strategy in AML.This article is highlighted in the In This Issue feature, p. 1426.

Leukocytapheresis for patients with acute myeloid leukemia presenting with hyperleukocytosis and leukostasis: a contemporary appraisal of outcomes and benefits

Introduction: Hyperleukocytosis, defined as a total white blood cell count (WBC) >50 or more commonly >100 × 10⁹ cells/L, is a presenting feature of acute myeloid leukemia (AML) in about 6-20% of cases and is associated with a higher risk of tumor lysis syndrome (TLS), disseminated intravascular coagulation (DIC), clinical leukostasis with end organ damage, and mortality.Areas covered: In this review, authors discuss the implications of hyperleukocytosis in AML and the current understanding of cytoreductive strategies with a focus on the use of leukocytapheresis.Expert commentary: Efforts to rapidly reduce peripheral myeloblasts have included the use of leukocytapheresis. Early studies demonstrated feasibility in reducing peripheral WBC and blast counts as well as clinically relevant patient outcomes which prompted its common use for many years. However, more recent data have directly challenged the previously touted reports of reduced TLS and DIC incidence as well as survival benefit, even in patients with clinical leukostasis. The use of leukocytapheresis remains highly controversial with wide practice variations among physicians, institutions, and countries given the lack of high-quality data, risks associated with leukocytapheresis itself, associated high costs, resource utilization, and lack of evidence-based clinical guidelines.

Acute Myeloid Leukaemia in Its Niche: the Bone Marrow Microenvironment in Acute Myeloid Leukaemia

Purpose of Review

Acute myeloid leukaemia (AML) is a heterogeneous malignancy for which treatment options remain suboptimal. It is clear that a greater understanding of the biology of the AML niche will enable new therapeutic strategies to be developed in order to improve treatment outcomes for patients.

Recent Findings

Recent evidence has highlighted the importance of the bone marrow microenvironment in protecting leukaemia cells, and in particular leukaemic stem cells from chemotherapy-induced cell death. This includes mesenchymal stem cells supporting growth and preventing apoptosis, and altered action and secretion profiles of other niche components including adipocytes, endothelial cells and T cells.

Summary

Here, we provide a detailed overview of the current understanding of the AML bone marrow microenvironment. Clinical trials of agents that mobilise leukaemic stem cells from the bone marrow are currently ongoing and show early promise. Future challenges will involve combining these novel therapies targeted at the AML niche with conventional chemotherapy treatment.

Serum levels of selected cytokines and soluble adhesion molecules in acute myeloid leukemia: Soluble receptor for interleukin-2 predicts overall survival

BACKGROUND

Acute myeloid leukemia (AML) cells are highly resistant to chemotherapeutic drugs. Cytokines and adhesion molecules may contribute to this resistance and affect treatment outcome. The aim of this study was to evaluate the independence and additional prognostic information of baseline serum levels of selected cytokines and soluble adhesion molecules, included in analyses with standard prognostic indicators.

METHODS

We used biochip array technology to measure levels of selected cytokines and soluble adhesion molecules in serum samples of 80 newly diagnosed AML patients. The markers of tumour microenvironment were analysed against high risk karyotype, hyperleucocytosis, higher age, lactic dehydrogenase levels and presence of FLT3-ITD and NPM-1 mutation.

RESULTS

All evaluated analytes were independent of standard prognostic indicators. Fifteen were associated with overall and eight with progression-free survival in univariate analysis. After correction for multiple testing, we identified soluble interleukin-2 receptor-α as an independent indicator of overall survival. Further, the soluble type I TNF-α receptor was close to statistical significance for both overall and progression-free survival.

CONCLUSIONS

Baseline levels of soluble interleukin-2 receptor-α predict overall survival in newly diagnosed AML. The TNF-α type I soluble receptor is a candidate prognostic marker in AML and is worth of further investigation.

Current and Future Molecular Targets for Acute Myeloid Leukemia Therapy

OPINION STATEMENT

Acute myeloid leukemia (AML) disease prognosis is poor and there is a high risk of chemo-resistant relapse for both young and old patients. Thus, there is a demand for alternative and target-specific drugs to improve the 5-year survival rate. Current treatment mainstays include chemotherapy, or mutation-specific targeting molecules including FLT3 inhibitors, IDH inhibitors, and monoclonal antibodies. Efforts to devise new, targeted therapy have included recent advances in methods for high-throughput genomic screening and the availability of computer-assisted techniques for the design of novel agents predicted to specifically inhibit mutant molecules involved in leukemogenesis. Crosstalk between the leukemia cells and the bone marrow microenvironment through cell surface molecules, such as the integrins αvβ3 and αvβ5, might influence drug response and AML progression. This review article focuses on current AML treatment options, new AML targeted therapies, the role of integrins in AML progression, and a potential therapeutic agent-integrin αvβ3 antagonist.

Malignancy: A Rare, Important and Poorly Understood Cause of Priapism

INTRODUCTION

Priapism is rare yet has the potential to inflict significant suffering on patients, often with lasting consequences such as erectile dysfunction, corporal muscle necrosis, and a loss of sexual function. Although rare, it is a pathology that has received little focus in the literature, particularly that caused by malignancy, and it is in this form that the long-term prognosis becomes particularly poor.

AIM

This review looks at malignant priapism in detail moving from the etiology and pathogenesis through investigations and management to provide an up-to-date picture.

METHODS

In so doing, more than 30 articles are reviewed and examined from databases such as PubMed. Significant cases are provided as examples to provide a comprehensive review of a topic that receives little attention but can cause significant patient morbidity.

MAIN OUTCOME MEASURE

The main outcome measure was the use of aspiration, sympathomimetics, and surgery as the main treatment modalities and how each one is used with regard to both the underlying etiology of the priapism and also the prognosis. We look at the need for treatment and how that relates to quality of life and erectile function thereafter.

RESULTS

Solid tumor invasion-both primary and secondary-and hematologic malignancies represent the key etiologies of malignant priapism and aggressive treatment is needed. Recovery of erectile function can occur if intracavernosal phenylephrine is quickly administered or distal shunts are placed; however, the prognosis is often poor, and subsequent chemotherapy treatment is often required.

CONCLUSION

The importance of a clear history and examination cannot be understated, and although the prognosis is often poor, this review hopes to give clinicians better understanding to be able to recognize malignancy as a potential cause of priapism. Ralph O, Shroff N, Johnson MJ, et al. Malignancy: A Rare, Important and Poorly Understood Cause of Priapism. J Sex Med 2021; 9:312-319.

Acute Respiratory Distress Syndrome in Cancer Patients

Acute respiratory distress syndrome (ARDS) is a heterogeneous form of acute, diffuse lung injury that is characterized by dysregulated inflammation, increased alveolar-capillary interface permeability, and non-cardiogenic pulmonary edema. In the general population, the incidence and mortality associated with ARDS over the last two decades have steadily declined in parallel with optimized approaches to pneumonia and other underlying causes of ARDS as well as increased utilization of multimodal treatment strategies that include lung-protective ventilation. In the cancer settings, significant declines in the incidence and mortality of ARDS over the past two decades have also been reported, although these rates remain significantly higher than those in the general population. Epidemiologic studies identify infection, including disseminated fungal pneumonias, as a major underlying cause of ARDS in the cancer setting. More than half of cancer patients who develop ARDS will not survive to hospital discharge. Those who do survive often face a protracted and often incomplete recovery, resulting in significant long-term physical, psychological, and cognitive sequelae. The residual organ dysfunction and poor functional status after ARDS may delay or preclude subsequent cancer treatments. As such, close collaboration between the critical care physicians and oncology team is essential in identifying and reversing the underlying causes and optimizing treatments for cancer patients with ARDS. This chapter reviews the diagnosis and common causes of ARDS in cancer and gives an update on the general management principles for cancer patients with ARDS in the ICU.