The Impact of All-trans-Retinoic Acid on the Coagulopathy of Acute Promyelocytic Leukemia

Hemorrhage in acute promyelocytic leukemia-fibrinolysis in focus

Coagulopathy continues to be a major challenge in the management of patients with acute promyelocytic leukemia (APL). Novel differentiating agents have led to improved survival in these patients, but perturbations in coagulation continue to have an impact on their prognosis. The most worrisome of coagulation disturbances is bleeding, which is not an uncommon cause of early death in APL. Despite this, there are no consistent predictors of this high risk of fatal hemorrhage in APL. In this context, the fibrinolytic system has been identified as a crucial role player in APL coagulopathy. However, the current guidelines for the management of APL give little regard to tests that measure the fibrinolytic system while giving more importance to close monitoring of conventional coagulation tests and platelet counts to identify the coagulopathy. More recently, viscoelastic tests have come to usefulness in determining global hemostasis and have been widely used for "diagnosing" hyperfibrinolysis in selected clinical settings. In this review, we attempt to describe risk assessment models for diagnosing APL coagulopathy, describe the possible application of viscoelastic tests in this setting, and persuade clinicians to reconsider the use of antifibrinolytics to improve survival of APL patients.

Phenotypes of Disseminated Intravascular Coagulation

Two phenotypes of disseminated intravascular coagulation (DIC) are systematically reviewed. DIC is classified into thrombotic and fibrinolytic phenotypes characterized by thrombosis and hemorrhage, respectively. Major pathology of DIC with thrombotic phenotype is the activation of coagulation, insufficient anticoagulation with endothelial injury, and plasminogen activator inhibitor-1-mediated inhibition of fibrinolysis, leading to microvascular fibrin thrombosis and organ dysfunction. DIC with fibrinolytic phenotype is defined as massive thrombin generation commonly observed in any type of DIC, combined with systemic pathologic hyperfibrinogenolysis caused by underlying disorder that results in severe bleeding due to excessive plasmin formation. Three major pathomechanisms of systemic hyperfibrinogenolysis have been considered: (1) acceleration of tissue-type plasminogen activator (t-PA) release from hypoxic endothelial cells and t-PA-rich storage pools, (2) enhancement of the conversion of plasminogen to plasmin due to specific proteins and receptors that are expressed on cancer cells and endothelial cells, and (3) alternative pathways of fibrinolysis. DIC with fibrinolytic phenotype can be diagnosed by DIC diagnosis followed by the recognition of systemic pathologic hyperfibrin(ogen)olysis. Low fibrinogen levels, high fibrinogen and fibrin degradation products (FDPs), and the FDP/D-dimer ratio are important for the diagnosis of systemic pathologic hyperfibrin(ogen)olysis. Currently, evidence-based treatment strategies for DIC with fibrinolytic phenotypes are lacking. Tranexamic acid appears to be one of the few methods to be effective in the treatment of systemic pathologic hyperfibrin(ogen)olysis. International cooperation for the elucidation of pathomechanisms, establishment of diagnostic criteria, and treatment strategies for DIC with fibrinolytic phenotype are urgent issues in the field of thrombosis and hemostasis.

Tissue factor activates the coagulation cascade in mouse models of acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is associated with a high risk of bleeding and thrombosis. APL patients have an activated coagulation system, hyperfibrinolysis, and thrombocytopenia. APL cells express tissue factor (TF), a receptor and cofactor for factor VII/VIIa. This study had 2 goals. Firstly, we measured biomarkers of coagulation and fibrinolysis activation as well as platelet counts and bleeding in both mouse xenograft and allograft models of APL. Secondly, we determined the effect of inhibiting TF on the activation of coagulation in these models. We observed increased levels of plasma thrombin-antithrombin complexes (TAT), D-dimer, and plasmin-antiplasmin complexes, reduced platelet counts, and increased tail bleeding in both mouse models of APL. Fibrinogen levels decreased in the xenograft model but not in the allograft model. In contrast, the red blood cell count decreased in the allograft model but not in the xenograft model. Inhibition of APL-derived human TF with an anti-human TF monoclonal antibody reduced the level of TAT, increased platelet count, and normalized tail bleeding in a xenograft model. Inhibition of all sources of TF (APL cells and host cells) in the allograft model with a rat anti-mouse TF monoclonal antibody decreased the levels of TAT but did not affect the platelet count. Our study demonstrates that TF plays a central role in the activation of coagulation in both the xenograft and allograft mouse models of APL. These APL mouse models can be used to investigate the mechanisms of coagulopathy and thrombocytopenia in APL.

Arteriovenous thrombosis, a complication of induction therapy with all-trans retinoic acid for acute promyelocytic leukemia: A case report

We report a case of arterial and venous thrombosis during induction therapy. This case emphasizes considering some degree of caution for thrombotic events in APL patients which was represented in our case as abdominal pain. Rapid initiation of anticoagulation and preventive measures is suggested for better management of the condition.

Clot-Targeted Antithrombotic Liposomal Nanomedicine Containing High Content of H2O2-Activatable Hybrid Prodrugs

Liposomes have been extensively explored as drug carriers, but their clinical translation has been hampered by their low drug-loading content and premature leakage of drug payloads. It was reasoned that vesicle-forming prodrugs could be incorporated into the lipid bilayer at a high molar fraction and therefore serve as a therapeutic agent as well as a structural component in liposomal nanomedicine. Boronated retinoic acid (BORA) was developed as a prodrug, which can self-assemble with common lipids to form liposomes at a high molar fraction (40%) and release all-trans retinoic acid (atRA) and hydroxybenzyl alcohol (HBA) simultaneously, in response to hydrogen peroxide (H2O2). Here, we report fucoidan-coated BORA-incorporated liposomes (f-BORALP) as clot-targeted antithrombotic liposomal nanomedicine with H2O2-triggered multiple therapeutic actions. In the mouse model of carotid arterial thrombosis, f-BORALP preferentially accumulated in the injured blood vessel and significantly suppressed thrombus formation, demonstrating their potential as targeted antithrombotic nanomedicine. This study also provides valuable insight into the development of vesicle-forming and self-immolative prodrugs to exploit the benefits of liposomal drug delivery.

The treatment of acute promyelocytic leukemia in 2023: Paradigm, advances, and future directions

The transformation of acute promyelocytic leukemia (APL) from an often fatal to highly curable cancer with long-term survival exceeding 90% is one of the greatest and most inspiring successes in oncology. A deeper understanding of the pathogenesis of APL heralded the introduction of highly effective therapies targeting the mutant protein that drives the disease, leading to the chemotherapy-free approach to cure almost all patients. In this review, we discuss the paradigm of treatment of APL in 2023, reinforce the high risk of early death without prompt initiation of treatment at first clinical suspicion, and dedicate a special focus to novel agents and future directions to improve cure rates and quality of life in patients affected by APL.

Coagulopathy in Patients with Low/Intermediate Risk Acute Promyelocytic Leukemia treated with First Line Arsenic Trioxide in Combination with All-Trans Retinoic Acid: A Monocentric Experience

No abstract  

Effect of Therapeutically Related Drugs on Coagulation-Anticoagulation Balance in Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) usually presents with a series of coagulation-anticoagulation disturbance. Early administration of All-trans retinoic acid (ATRA) can reduce the risk of bleeding, but the potential for thrombosis needs to be addressed in some cases. The role of arsenic agent in correcting coagulation disorder remains to be studied, but oral arsenic agent shows potential advantages in coagulation recovery compared with intravenous agent, and chemotherapy can aggravate the progress of coagulation disease. In addition to early application of ATRA, avoiding invasive procedures and transfusion support can reduce the risk of bleeding. Whether the administration of heparin, thrombomodulin, recombinant factor VIIa or antifibrinolytics reduces the risk of bleeding and thrombosis associated with APL remains to be further explored, and their routine use outside of clinical trials is not recommended. This article reviews the effects of related drugs on coagulation-anticoagulation balance in APL patients.

Acute promyelocytic leukemia presenting as recurrent venous and arterial thrombotic events: a case report and review of the literature

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia characterized by a translocation of chromosomes 15 and 17, creating an alternation in the retinoic acid receptor-alpha (RAR-alpha) gene. This leads to excessive medullary production of promyelocytic blasts, which are frequently associated with the hemorrhagic complications seen in APL. In contrast, APL-associated thrombosis occurs much less frequently and is an underappreciated life-threatening manifestation of the disease. Most thrombotic events occur during induction chemotherapy with all-transretinoic acid and are rarely seen as the initial presentation on APL. Here we report an exceedingly rare case of a patient with recurrent venous and arterial thrombotic events, including deep vein thrombosis, bilateral segmental pulmonary embolism, an ischemic stroke, splenic infarcts, and renal infarcts, later found to have APL. We aim to discuss the most recent understanding of the pathogenesis of APL-associated thrombosis and to summarize the literature of this rare presentation of APL.

Coagulopathy in Acute Promyelocytic Leukemia: Can We Go Beyond Supportive Care?

Acute promyelocytic leukemia (APL) is characterized by frequent complications due to a distinct coagulopathy. While advances in treatments have improved long-term survival, hemorrhagic and thrombotic complications remain the most common causes of death and morbidity. Improved understanding of the mechanisms of the coagulopathy associated with APL may lead to therapeutic interventions to mitigate the risk of hemorrhage and thrombosis.

LncRNA KCNQ1OT1 activated by c-Myc promotes cell proliferation via interacting with FUS to stabilize MAP3K1 in acute promyelocytic leukemia

Uncontrolled proliferation is the hallmark of cancer cells. Previous studies mainly focused on the role of protein-coding genes in cancer cell proliferation. Emerging evidence showed that long non-coding RNAs (lncRNAs) also play critical roles in cancer cell proliferation and growth. LncRNA KCNQ1OT1 is found to contribute to carcinogenesis, but its role in acute promyelocytic leukemia (APL) is unclear. In this study, by analyzing data from Gene Expression Omnibus, The Cancer Genome Atlas database and our clinical samples, we found that KCNQ1OT1 was selectively highly expressed in APL. Functional assays demonstrated that knockdown of KCNQ1OT1 reduced APL cell proliferation and increased apoptosis. Further evidence showed that KCNQ1OT1 was mainly located in the cytoplasm of APL patient-derived NB4 cells and APL patient bone marrow samples. Mechanistically, KCNQ1OT1 bound to RNA binding protein FUS, and silencing either KCNQ1OT1 or FUS reduced the expression level and stability of MAP3K1 mRNA. Whereas KCNQ1OT1 and FUS did not affect each other. Importantly, knockdown of MAP3K1 impaired APL cell proliferation. Finally, c-Myc transactivated KCNQ1OT1 in APL cells through binding to its promoter while knockdown of c-Myc decreased KCNQ1OT1 expression. Our results not only revealed that c-Myc transactivated KCNQ1OT1 and upregulated KCNQ1OT1 promoted APL cell proliferation, but also demonstrated that KCNQ1OT1 bound to FUS to synergistically stabilize MAP3K1 mRNA, thus facilitating APL cell proliferation. This study established a previously unidentified role of KCNQ1OT1 in the development of APL, and KCNQ1OT1 may serve as a potential therapeutic target for APL.

The value of FDP/FIB and D-dimer/FIB ratios in predicting high-risk APL-related thrombosis

Hemorrhage is the typical manifestation of APL-related coagulopathy while thrombosis is infrequently reported. In a retrospective analysis with 33 patients with hyperleukocytic APL, we found 6 out of 33 hyperleukocytic APL patients presented with thrombosis rather than hemorrhage. A notable feature in these high-risk APL patients with thrombosis is that there were no significant abnormalities in fibrinogen (FIB), prothrombin time (PT) and activated partial thromboplastin time (APTT). Compared with the normal ranges, both the high-risk APL patients with thrombosis and the high-risk APL patients with hemorrhage had a significant increase in fibrinogen degradation product (FDP) and d-dimer levels. However, the group with hemorrhage had noticeably higher plasma levels of FDP and d-dimer than the group with thrombosis. To find a close relationship between coagulation markers and the onset of thrombotic events in patients with high-risk APL, the potential effects of FDP/FIB and d-dimer/FIB ratios as risk markers were investigated. We demonstrated that FDP/FIB and d-dimer/FIB ratios in the patients with high-risk APL with thrombosis showed higher ratios than the normal range but significantly lower ratios than the patients with high-risk APL-related hemorrhage. Our data demonstrated that the alteration in FDP/FIB and d-dimer/FIB ratios have more significant relevance than the levels of FIB, FDP or d-dimer as potential factors for predicting thrombosis and may help with designing more appropriately risk-adapted treatment protocols or personalized therapy.

Analysis of the role of thrombomodulin in all-trans retinoic acid treatment of coagulation disorders in cancer patients

BACKGROUND

Clinical studies have shown that all-trans retinoic acid (RA), which is often used in treatment of cancer patients, improves hemostatic parameters and bleeding complications such as disseminated intravascular coagulation (DIC). However, the mechanisms underlying this improvement have yet to be elucidated. In vitro studies have reported that RA upregulates thrombomodulin (TM) expression on the endothelial cell surface. The objective of this study was to investigate how and to what extent the TM concentration changes after RA treatment in cancer patients, and how this variation influences the blood coagulation cascade.

RESULTS

In this study, we introduced an ordinary differential equation (ODE) model of gene expression for the RA-induced upregulation of TM concentration. Coupling the gene expression model with a two-compartment pharmacokinetic model of RA, we obtained the time-dependent changes in TM and thrombomodulin-mRNA (TMR) concentrations following oral administration of RA. Our results indicated that the TM concentration reached its peak level almost 14 h after taking a single oral dose (110 [Formula: see text]) of RA. Continuous treatment with RA resulted in oscillatory expression of TM on the endothelial cell surface. We then coupled the gene expression model with a mechanistic model of the coagulation cascade, and showed that the elevated levels of TM over the course of RA therapy with a single daily oral dose (110 [Formula: see text]) of RA, reduced the peak thrombin levels and endogenous thrombin potential (ETP) up to 50 and 49%, respectively. We showed that progressive reductions in plasma levels of RA, observed in continuous RA therapy with a once-daily oral dose (110 [Formula: see text]) of RA, did not affect TM-mediated reduction of thrombin generation significantly. This finding prompts the hypothesis that continuous RA treatment has more consistent therapeutic effects on coagulation disorders than on cancer.

CONCLUSIONS

Our results indicate that the oscillatory upregulation of TM expression on the endothelial cells over the course of RA therapy could potentially contribute to the treatment of coagulation abnormalities in cancer patients. Further studies on the impacts of RA therapy on the procoagulant activity of cancer cells are needed to better elucidate the mechanisms by which RA therapy improves hemostatic abnormalities in cancer.

Multicenter randomized trial of arsenic trioxide and Realgar-Indigo naturalis formula in pediatric patients with acute promyelocytic leukemia: Interim results of the SCCLG-APL clinical study

Intravenous arsenic trioxide (ATO) has been adopted as the first‐line treatment for acute promyelocytic leukemia (APL). Another arsenic compound named the Realgar‐Indigo naturalis formula (RIF), an oral traditional Chinese medicine containing As₄S₄, has been shown to be highly effective in treating adult APL. In the treatment of pediatric APL, the safety and efficacy of RIF remains to be confirmed. This randomized, multicenter, and noninferiority trial was conducted to determine whether intravenous ATO can be substituted by oral RIF in the treatment of pediatric APL. From September 2011 to January 2017, among 92 patients who were 16 years old or younger with newly diagnosed PML‐RARa positive APL, 82 met eligible criteria and were randomly assigned to ATO (n = 42) or RIF (n = 40) group. The remaining 10 patients did not fulfilled eligible criteria because five did not accept randomization, four died and one had hemiplegia prior to arsenic randomization due to intracranial hemorrhage or cerebral thrombosis. Induction and consolidation treatment contained ATO or RIF, all‐trans‐retinoic acid and low intensity chemotherapy. End points included event‐free survival (EFS), adverse events and hospital days. After a median 3‐year follow‐up, the estimated 5‐year EFS was 100% in both groups, and adverse events were mild. However, patients in the RIF group had significantly less hospital stay than those in the ATO group. This interim analysis shows that oral RIF is as effective and safe as intravenous ATO for the treatment of pediatric APL, with the advantage of reducing hospital stay. Final trial analysis will reveal mature outcome data.

Multiple acute ischemic strokes as the onset manifestation of acute promyelocytic leukemia

Acute promyelocytic leukemia often manifests with hemorrhagic diathesis, thrombotic events being much rarer. This is the case of a 59-year-old patient with thrombotic cerebro-vascular complications as the onset manifestation of acute promyelocytic leukemia.

Successful treatment of disseminated intravascular coagulation by recombinant human soluble thrombomodulin in patients with acute myeloid leukemia

Disseminated intravascular coagulation (DIC) is a life-threatening condition that frequently occurs in patients with hematologic malignancies. Currently, recombinant human soluble thrombomodulin (rTM) is a therapeutic DIC drug that is manufactured and sold in Japan only. We evaluated the efficacy of rTM compared to that of gabexate mesilate (GM), which was previously used routinely for treating DIC in Japan, in patients with acute myeloid leukemia (AML). This retrospective study enrolled 43 AML patients, including 17 with acute promyelocytic leukemia (APL), that was complicated with DIC. DIC resolution rates in non-APL AML and rTM-treated APL patients were 68.4% and 81.8%, respectively. In non-APL AML patients, the duration of rTM administration was significantly shorter than that of GM (7 vs 11 days), suggesting that rTM could improve DIC earlier than GM, although rTM was used in patients with more severe DIC. Moreover, treatment with rTM significantly improved DIC score, fibrinogen, fibrin/fibrinogen degradation product (FDP), and prothrombin time (PT) ratio. Conversely, treatment with GM only improved the DIC score and FDP. In APL patients, the duration of rTM administration was also significantly shorter than that of GM. No severe side effects associated with the progression of bleeding were observed during rTM administration. These findings suggest that rTM is safe, and its anti-DIC effects are more prompt than GM for treating AML patients with DIC.

Mechanisms and management of coagulopathy in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a subtype of leukemia which is associated with unique and distinctive coagulopathy. In the absence of treatment it is rapidly fatal and even after initiation of therapy the major cause of early mortality is related to hemorrhagic complications. The coagulopathy can be exacerbated with the start of treatment. In the absence of early hemorrhage related deaths the probability of cure exceeds 90% in low and intermediate risk patients and 80% even in high risk patients, highlighting the importance of understanding the pathophysiology of this complication and instituting prompt and appropriate management strategies. The coagulopathy in APL is complex and results from a combination of thrombocytopenia, disseminated intravascular coagulation and hyperfibronlysis. Recently the effect of all-trans retinioc acid (ATRA) induced ETosis on exacerbating coagulopathy in the first few days after starting therapy with this agent raises the potential for potentially novel strategies to reduce the risk of hemorrhage. Currently management is mainly related to rapid initiation of therapy with ATRA along with appropriate and adequate replacement of blood products to correct the coagulopathy. There is limited role for the use of low dose anti-coagulants and anti-fibrinolytic agents in the initial management of this disease. There is limited data on the use of rFVIIa or the use of global tests of hemostasis in the management of this condition.

Recent advances in acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APML) is a subtype of leukaemia arising from a distinct reciprocal translocation involving chromosomes 15 and 17, which results in the PML-RARA fusion gene. Over the past three decades, APML has been transformed from a highly fatal disease to a highly curable one. This drastic improvement is because of the introduction of a new treatment strategy with all-trans retinoic acid and, more recently, arsenic trioxide. The revolutionary treatment of APML has also paved the way for a new cancer treatment, which is genetically targeted therapy. In this review, we look into this amazing journey of transformation and provide recent advances in the management of APML.

The Effect of Anthracycline-Based (Epirubicin) Adjuvant Chemotherapy on Plasma TAFI and PAI-1 Levels in Operable Breast Cancer

An increased incidence of thromboembolic events has been described in women receiving systemic chemotherapy for breast cancer. The effect of anthracycline-based adjuvant chemotherapy regimens on fibrinolytic system markers of plasminogen activator inhibitor-1 (PAI-1) and thrombin activitable fibrinolysis inhibitor (TAFI) was investigated in patients with operable breast cancer. Twenty-four patients with operable breast cancer (median age, 54.5 years; range, 37-72 years) enrolled in our study. Stage I-II and stage IIIA cases received EC (Epirubicin 90 mg/m2/d1, I.V. and cyclophosphamide 600 mg/m2/d1, I.V.) and FEC (5-fluorouracil 500 mg/m2/d1, I.V., epirubicin 100 mg/m2/d1, I.V., and cyclophosphamide 500 mg/m2/d1, I.V.) as an adjuvant chemotherapy regimen, respectively. Each group consisted of 12 patients. Blood samples were obtained at baseline and just before the third cycle of EC and fourth cycle of FEC chemotherapy regimens. Plasma TAFI antigen and PAI-1 levels did not disclose any statistical difference between basal and postchemotherapy levels within each group and between two groups. Although postchemotherapy D-dimer levels were statistically higher in the FEC group than in the EC group, results in both groups were within normal ranges. More studies concerning the role of fibrinolytic system in breast cancer patients receiving chemotherapy, probably including cases with advanced stage and with different chemotherapy regimens and dose intensities, are needed.

Asphyxia by Drowning Induces Massive Bleeding Due To Hyperfibrinolytic Disseminated Intravascular Coagulation

OBJECTIVE

To date, no study has systematically investigated the impact of drowning-induced asphyxia on hemostasis. Our objective was to test the hypothesis that asphyxia induces bleeding by hyperfibrinolytic disseminated intravascular coagulation.

DESIGN

Observational study.

SETTING

A 2,100-bed tertiary care facility in Vienna, Austria, Europe.

PATIENTS

All cases of drowning-induced asphyxia (n=49) were compared with other patients with cardiopulmonary resuscitation (n=116) and to patients with acute promyelocytic leukemia (n=83). Six drowning victims were investigated prospectively. To study the mechanism, a forearm-ischemia model was used in 20 volunteers to investigate whether hypoxia releases tissue plasminogen activator.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eighty percent of patients with drowning-induced asphyxia developed overt disseminated intravascular coagulation within 24 hours. When compared with nondrowning cardiac arrest patients, drowning patients had a 13 times higher prevalence of overt disseminated intravascular coagulation at admission (55% vs 4%; p<0.001). Despite comparable disseminated intravascular coagulation scores, acute promyelocytic leukemia patients had higher fibrinogen but lower d-dimer levels and platelet counts than drowning patients (p<0.001). Drowning victims had a three-fold longer activated partial thromboplastin time (124 s; p<0.001) than both nondrowning cardiac arrest and acute promyelocytic leukemia patients. Hyperfibrinolysis was reflected by up to 1,000-fold increased d-dimer levels, greater than 5-fold elevated plasmin antiplasmin levels, and a complete absence of thrombelastometric clotting patterns, which was reversed by antifibrinolytics and heparinase. Thirty minutes of forearm-ischemia increased tissue plasminogen activator 31-fold (p<0.001).

CONCLUSIONS

The vast majority of drowning patients develops overt hyperfibrinolytic disseminated intravascular coagulation, partly caused by hypoxia induced tissue plasminogen activator release. Antifibrinolytics and heparinase partially reverse the abnormal clotting patterns. Severe activated partial thromboplastin time prolongation may be a marker of combined hyperfibrinolytic afibrinogenemia and autoheparinization in drowning-related asphyxia.

Acute Promyelocytic Leukemia: A Review and Discussion of Variant Translocations

The majority of patients with acute promyelocytic leukemia (APL) manifest the t(15;17)(q24.1;q21.2) translocation; however, a minor but significant proportion of patients with APL harbor complex, cryptic, or variant translocations, which typically involve RARA. With the exception of ZBTB16/RARA, these variants have similar morphologic and immunophenotypic features as classic APL. Study of the variant forms of APL not only gives insight into the pathogenesis of APL but also allows us to understand the mechanism of retinoid therapy. It is important to identify these cryptic and variant translocations because certain variants, including ZBTB16/RARA and STAT5B/RARA, are resistant to treatment with all-trans retinoic acid, arsenic trioxide, and anthracyclines.

A review in the treatment of oncologic emergencies

AIM

Oncologic emergencies are often categorized as a group of metabolic abnormalities associated with the diagnosis of cancer or the initiation of chemotherapy for treatment. These syndromes often arise in the acute setting, demanding an accurate knowledge of the associated condition and current treatment. In this review, we evaluate five oncologic emergencies: tumor lysis syndrome, hypercalcemia, hyponatremia, spinal cord compression, and disseminated intravascular coagulation.

SUMMARY

Oncologic emergencies are often diverse in etiology and are often associated with the initiation of chemotherapy. Tumor lysis syndrome presents as severe electrolyte abnormalities that need to be addressed urgently, sometimes prior to initiation of chemotherapy. Hypercalcemia of malignancy is treated with aggressive rehydration, furosemide, and intravenous bisphosphonates. If a patient with cancer presents with normovolemic hyponatremia, syndrome of inappropriate antidiuretic hormone should be suspected. Malignant spinal cord compression happens when cancer cells grow in, or near to, the spine and press on the spinal cord and nerves. This causes swelling and a reduction in the blood supply to the spinal cord and nerve roots. Disseminated intravascular coagulation is characterized by systemic activation of blood coagulation, which results in generation and deposition of fibrin, leading to microvascular thrombi in various organs and contributing to multiple organ dysfunction syndrome.

CONCLUSION

Knowledge of oncology emergencies is critical to the understanding of these emergent syndromes in oncology patients. Each of these disease states requires careful evaluation of the patient's symptoms, monitoring parameters for conditions and supportive care measures and interventions.

Platelets in cancer metastasis: To help the "villain" to do evil

Cancer progress is accompanied by platelet activation and thrombotic complications. Platelets are a dangerous alliance of cancer cells, and are a close engager in multiple processes of cancer metastasis. Platelet adhesion to cancer cells forms a protective cloak that helps cancer cells to escape immune surveillance and natural killer cell-mediated cytolysis. Platelets facilitate tethering and arrest of disseminated cancer cells in the vasculature, enhance invasive potentials and thus extravasation of cancer cells. Moreover, platelets recruit monocytes and granulocytes to the sites of cancer cell arrest, and collaborate with them to establish a pro-metastatic microenvironment and metastatic niches. Platelets also secret a number of growth factors to stimulate cancer cell proliferation, release various angiogenic regulators to regulate tumor angiogenesis and subsequently promote cancer growth and progress. Albeit platelets are helping the "villain" cancer to do evil, the close engagements of platelets in cancer metastasis and progress can be used as the intervention targets for new anti-cancer therapeutic developments. Platelet-targeted anti-cancer strategy may bring in novel anti-cancer treatments that can synergize the therapeutic effects of chemotherapies and surgical treatments of cancer.

Cancer-related coagulopathies

The association between cancer and thrombosis is known for years. Besides the well-recognized connection between venous thromboembolism and malignancies, there are, however, also other manifestations of cancer-related activation of coagulation and (micro)vascular dysfunction. In fact, coagulation derangements and vascular disturbances in patients with cancer cover a wide spectrum of diseases and various clinical manifestations. In this review we will highlight the mechanisms that play a role in the systemic activation of coagulation in cancer patients, in its most severe form manifested as disseminated intravascular coagulation. Clinically, disseminated intravascular coagulation (DIC) in cancer has in general a less fulminant presentation than the types of DIC complicating sepsis and trauma. A more gradual, but also more chronic, systemic activation of coagulation can proceed subclinically. The relationship between venous thromboembolism and cancer as a consequence of the hypercoagulability will be discussed as well. Furthermore, the role of perturbed endothelium in the pathogenesis of microvascular dysfunction and microangiopathy in particular in the setting of cancer and chemo- or radiotherapy will be reviewed.

ATRA-induced cerebral sinus thrombosis

All-trans retinoic acid (ATRA) and Idarubicin are part of the AIDA protocol employed for the treatment of Acute promyelocytic leaukaemia (APML) and has been associated with marked improvement in the prognosis. However, it is known to worsen the haematological picture during the course of induction of therapy. Herein, we present a case of an APML patient who developed a rare documented incidence of cerebral sinus thrombosis, first noticed as an ophthalmology referral. This 22 year old lady, a known APML patient was then started on chemotherapy based on AIDA protocol but 17 days into the initiation of therapy, she began to complain of blurred vision on the right eye. Anterior segments were normal but both fundi showed papilloedema with peripapillary haemorrhages. A contrast MRI that was then ordered showed multiple filling defects in numerous venous sinuses. She was started on anticoagulant treatment and the findings resolved. Though a rare case of its side-effects, ATRA usage in APML has a multitude of presentations since its primary pathology lies in the inherent pro-coagulant potential.

Rapid detection of t(15;17)(q24;q21) in acute promyelocytic leukaemia by microwave-assisted fluorescence in situ hybridization

Acute promyelocytic leukaemia (APL) is a hematologic malignancy characterized by the rearrangement of the PML and RARα genes, mostly due to a reciprocal chromosomal translocation t(15;17)(q24;q21). A quick APL diagnosis is essential for starting a prompt suitable therapy. We describe a new rapid diagnostic laboratory approach to detect the PML-RARα rearrangement, which gives clear genetic results within 30 min of hybridization. It combines quick cell harvesting, fluorescence in situ hybridization performed with commercial DNA probe and microwave beams supplied by a domestic microwave oven. Copyright © 2015 John Wiley & Sons, Ltd.

Thrombocytopenia Possibly Induced by Etretinate in a Psoriatic Patient

A patient with psoriasis vulgaris developed multiple purpura on the extremities and hemorrhage at the oral mucosa and gingiva with marked thrombocytopenia. This thrombocytopenia was possibly induced by a retinoid agent, etretinate, from the clinical course and data. The total amount of etretinate administered was 2,410 mg over 191 days (41.9 mg/kg body weight, average 15.3 mg/day). A platelet transfusion partially restored the platelet count and the purpura and gingival hemorrhage disappeared approximately 10 days after the cessation of etretinate. However, the platelet count remains at 60-80 x 103/mm3 after two and a half years without etretinate therapy. Although there are only a few case reports of etretinate-induced thrombocytopenia, we should pay more attention to the peripheral platelet count during etretinate therapy.

Comparative study of the efficacy of Wright-Giemsa stain and Liu's stain in the detection of Auer rods in acute promyelocytic leukemia

In view of the importance of Auer rods in the rapid diagnosis of acute promyelocytic leukemia, we compared the results of Wright-Giemsa stain and Liu's stain (a rapid and simple stain, which is also a kind of modified Romanowsky stain) in the detection of Auer rods. This study was based on 53 cases of acute promyelocytic leukemia. Two staining methods were respectively performed on the bone marrow smears of these cases, and presence of Auer rods as well as nuclear features, cytoplasmic features and the degree of granularity of the cytoplasm were compared in each case. Our results showed that the occurrence of Auer rods as well as faggots in leukemic promyelocytes were significantly higher under Liu's stain than under Wright-Giemsa stain. Significant differences also existed in the occurrence of hypergranular cells and cytoplasmic protrusions between smears stained with Liu's stain and Wright-Giemsa stain. Liu's stain is important for the rapid diagnosis of suspicious APL, especially in recognizing Auer rods.

Thrombosis and hemostatic abnormalities in hematological malignancies

There is a paucity of data that pertain to thrombosis in patients with hematological malignancies. Recent studies showed that patients with lymphoma, multiple myeloma, and acute leukemia have an increased thrombotic risk, particularly at the time of diagnosis and during chemotherapy. We searched the PubMed database for articles on thromboembolic complications in patients with hematological malignancies published between 1996 and 2013. The incidence of thrombotic events is variable, and is influenced by the type and the stage of hematological malignancy, the antitumor therapy, and the use of central venous devices. The pathogenesis of thromboembolic disease in hematological malignancies is multifactorial. Tumor cell-derived procoagulant, fibrinolytic, or proteolytic factors, and inflammatory cytokines affect clotting activation, and chemotherapy and immunomodulatory drugs increase the thrombotic risk in patients with lymphoma, acute leukemia, and multiple myeloma. Infections might also contribute to the pathogenesis of the thromboembolic complications: endotoxins from gram-negative bacteria induce the release of tissue factor, tumor necrosis factor and interleukin-1b, and gram-positive organisms can release bacterial mucopolysaccharides that directly activate factor XII. In the setting of plasma cell dyscrasias, hyperviscosity, decreased fibrinolysis, procoagulant autoantibody production, inflammatory cytokines, acquired activated protein C resistance, and the prothrombotic effects of antimyeloma agents might be the cause of thromboembolic complications. Anticoagulant therapy is very complicated because of high risk of hemorrhage. Therefore, an accurate estimate of a patient's thrombotic risk is essential to allow physicians to target thromboprophylaxis in high-risk patients.

Contemporary treatment of APL

Acute promyelocytic leukemia (APL) is characterized by coagulopathy, leukopenic presentation and sensitivity to anthracyclines, all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). For the last 25 years, APL has been treated with a combination of ATRA and chemotherapy for induction followed by consolidation and maintenance therapy. This general treatment approach has resulted in cure rates of 80-90 %. ATO, originally approved in relapsed APL, has been incorporated into contemporary upfront treatment regimens with excellent response rates. Recent studies show that most patients with APL can be cured with ATRA and ATO alone, eliminating cytotoxic chemotherapy and resulting in superior outcomes compared to standard treatment. We will herein review historical treatment of APL, treatment considerations in specific patient populations, and therapeutic updates.

Cerebral venous and sinus thrombosis in a patient with acute promyelocytic leukemia during all-trans retinoic acid induction treatment

Cerebral venous and sinus thrombosis is a rare cerebrovascular disorder, which seldom represents a complication of acute promyelocytic leukemia (APL). As a part of the coagulopathy of APL, thrombosis is a less recognized and underestimated life-threatening manifestation and is overshadowed by the more obvious bleeding complications. Here, we described a 28-year-old woman with APL who developed massive thrombosis of the cerebral sinuses while on induction treatment with all-trans retinoic acid. On the basis of this report, the potential pathogenic mechanisms and the diagnosis based on magnetic resonance imaging (MRI) combined with magnetic resonance venogram (MRV) are discussed. Early anticoagulant therapy contributed to the progressive dissolution of the thrombosis, as documented by MRI, with the complete disappearance of neurological signs without sequelae. Given the increasing recognition of thromboembolic events in APL, the use of prophylactic anticoagulation during induction therapy may need to be redefined.

Thrombomodulin alfa treatment in patients with acute promyelocytic leukemia and disseminated intravascular coagulation: a retrospective analysis of an open-label, multicenter, post-marketing surveillance study cohort

INTRODUCTION

Patients with acute promyelocytic leukemia (APL) can develop disseminated intravascular coagulation (DIC) that results in life-threatening hemorrhagic complications. Studies regarding the safety and efficacy of thrombomodulin alfa (TM-α; recombinant human soluble thrombomodulin) in patients with APL and DIC are limited.

MATERIALS AND METHODS

A retrospective evaluation was performed on a cohort of 172 patients with APL from an open-label, multicenter, post-marketing surveillance study of TM-α.

RESULTS

Of the 172 patients, 31 were relapse/refractory APL patients, and 141 were newly diagnosed APL patients. Within the first 30 days, 24 patients (14.0%) died, and six of those deaths (3.5%) were due to hemorrhage. In total, 12 patients (7.0%) had severe hemorrhagic complications. Both the early death rate due to hemorrhage as well as the severe hemorrhage rate did not exceed those in some recent population-based studies of patients with APL. Forty-nine patients received TM-α prior to the initiation of antileukemic treatment, and one patient experienced hemorrhagic early death (ED), suggesting that early TM-α treatment appeared to result in a reduction in the hemorrhagic ED rate. Moreover, TM-α improved coagulopathy regardless of concomitant all-trans retinoic acid treatment.

CONCLUSIONS

This study confirmed the safety and efficacy of TM-α in daily clinical practice for patients with APL and DIC. TM-α appeared to reduce hemorrhagic early deaths due to DIC in patients with APL who were receiving antileukemic treatment.

Validation of a liquid chromatography-electrospray ionization-tandem mass spectrometry method for determination of all-trans retinoic acid in human plasma and its application to a bioequivalence study

A sensitive, reliable and specific LC-MS-MS method was developed and validated for the identification and quantitation of all-trans retinoic acid (ATRA) in human plasma. Acitretin was used as the internal standard (IS). After liquid-liquid extraction of 500 μL plasma with methyl tert-butyl ether (MTBE), ATRA and the IS were chromatographed on a HyPURITY C18 column (150 mm × 2.1 mm, 5 μm) with the column temperature set at 40 °C. The mobile phase was consisted of 40% phase A (MTBE–methanol–acetic acid, 50:50:0.5, v/v) and 60% phase B (water–methanol–acetic acid, 50:50:0.5, v/v) with a flow rate of 0.3 mL/min. The API 4000 triple quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM) mode via the positive electrospray ionization interface using the transition m/z 301.4 → 123.1 for ATRA and m/z 326.9 → 177.1 for IS, respectively. The calibration curve was linear over the range of 0.45–217.00 ng/mL (r ≥ 0.999) with a lower limit of quantitation (LLOQ) of 0.45 ng/mL. The intra- and inter-day precisions values were below 8% relative standard deviation and the accuracy was from 98.98% to 106.19% in terms of relative error. The validated method was successfully applied in a bioequivalence study of ATRA in Chinese healthy volunteers.

Acute promyelocytic leukemia presenting as ischemic stroke in young

Coagulopathy in acute promyelocytic leukemia (APL) is a very complex disorder and is believed to result from interplay of various factors. Usually patients present with bleeding tendencies which can be life threatening. However, a few present with thromboses. Here, we report a young male with APL who presented with ischemic stroke in young.

Update on optimal management of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a malignant accumulation of immature myeloid cells in the marrow, presenting with impaired hematopoiesis and its attendant complications, including bleeding, infection, and organ infiltration. Chromosomal abnormalities remain the most powerful predictors of AML prognosis and help to identify a subgroup with favorable prognosis. However, the majority of AML patients who are not in the favorable category succumb to the disease. Therefore, better efforts to identify those patients who may benefit from more aggressive and investigational therapeutic approaches are needed. Newer molecular markers aim at better characterizing the large group of intermediate-risk patients and to identify newer targets for therapy. A group that has seen little improvement over the years is the older AML group, usually defined as age ≥ 60. Efforts to develop less intensive but equally efficacious therapy for this vulnerable population are underway.

All-trans retinoic acid in the treatment of pediatric acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a rare form of acute myeloid leukemia with specific epidemiological, pathogenetic and clinical features. Its frequency varies widely among nations, with a decreased incidence among 'Nordic' origin populations. The molecular hallmark of the disease is the presence of a balanced reciprocal translocation resulting in the PML/RAR-α gene fusion, which represents the target of the all-trans retinoic acid (ATRA) therapy. The introduction of ATRA in conjunction with anthracyclines marked a turning point in the treatment of APL, previously associated with a significant morbidity and mortality. Nowadays the standard front-line therapy for pediatric APL includes ATRA in every phase of the treatment, resulting in a complete remission rate of 90-95%. Here we provide an overview of the role of ATRA in the treatment of pediatric APL, summarizing the most relevant clinical results of recent decades and investigating future therapeutic perspectives for children with APL.

Thrombosis in acute promyelocytic leukemia

INTRODUCTION

Compared to bleeding, major thromboses are a less commonly encountered problem in acute promyelocytic leukemia (APL), and our knowledge about the epidemiology of major thromboses in APL stems mainly from individual case reports. The purpose of this study was to provide a better understanding of the epidemiology of APL-related thrombosis as a first step towards developing preventive strategies.

MATERIALS AND METHODS

We report a rare case of catastrophic acute myocardial infarction in a patient with APL while she developed the all-trans retinoic acid (ATRA) syndrome. We describe the pathogenesis of APL-related thrombosis and review all previously reported cases of major thromboses in APL.

RESULTS

We found 94 cases of major thromboses in patients with APL. Both genders were almost equally affected. More than 80% of events occurred before or during induction therapy with deep vein thrombosis/pulmonary embolism (DVT/PE), cardiac events, and cerebrovascular accidents (CVA) constituting more than 75% of all cases. Arterial events were slightly more common than venous events. Only 2 arterial events occurred after completion of induction therapy. Thrombosis was associated with life-threatening hemorrhage in about 15%, significant coagulative defects in about 50%, and ATRA syndrome in about 13% of cases. Cardiac thrombotic events, DVT/PE, and CVA were associated with ATRA syndrome in 24%, 4.5%, and 5% of cases, respectively (p=0.09). None of the observed trends and associations reached statistical significance.

CONCLUSIONS

This review advances our understanding of the epidemiology of major thromboses in APL. With accumulation of more cases in the literature, some of our results may become statistically significant.

Characterization of plasminogen binding to NB4 promyelocytic cells using monoclonal antibodies against receptor-induced binding sites in cell-bound plasminogen

The NB4 promyelocytic cell line exhibits many of the characteristics of acute promyelocytic leukemia blast cells, including the translocation (15 : 17) that fuses the PML gene on chromosome 15 to the RARα gene on chromosome 17. These cells have a very high fibrinolytic capacity. In addition to a high secretion of urokinase, NB4 cells exhibit a 10-fold higher plasminogen binding capacity compared with other leukemic cell lines. When tissue-type plasminogen activator was added to acid-treated cells, plasmin generation was 20–26-fold higher than that generated by U937 cells or peripheral blood neutrophils, respectively. We found that plasminogen bound to these cells can be detected by fluorescence-activated cell sorting using an antiplasminogen monoclonal antibody that specifically reacts with this antigen when it is bound to cell surfaces. All-trans retinoid acid treatment of NB4 cells markedly decreased the binding of this monoclonal antibody. This cell line constitutes a unique model to explore plasminogen binding and activation on cell surfaces that can be modulated by all-trans retinoid acid treatment.

Retinoic acid alleviates Con A-induced hepatitis and differentially regulates effector production in NKT cells

Retinoic acid (RA) is a diverse regulator of immune responses. Although RA promotes natural killer T (NKT) cell activation in vitro by increasing CD1d expression on antigen-presenting cells (APCs), the direct effects of RA on NKT-cell responses in vivo are not known. In the present study, we demonstrated the effect of RA on the severity of Con A-induced hepatitis and molecular changes of NKT cells. First, we demonstrated that Con A-induced liver damage was ameliorated by RA. In correlation with cytokine levels in serum, RA regulated the production of IFN-γ and IL-4 but not TNF-α by NKT cells without influencing the NKT-cell activation status. However, RA did not alleviate α-GalCer-induced liver injury, even though it reduced IFN-γ and IL-4 but not TNF-α levels in serum. This regulation was also detected when liver mononuclear cells (MNCs) or NKT hybridoma cells were treated with RA in vitro. The regulatory effect of RA on NKT cells was mediated by RAR-α, and RA reduced the phosphorylation of MAPK. These results suggest that RA differentially modulates the production of effector cytokines by NKT cells in hepatitis, and the suppressive effect of RA on hepatitis varies with the pathogenic mechanism of liver injury.

Bleeding and thrombosis in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) has evolved from being a deadly to a highly curable disease, due to targeted molecular therapy with all-trans retinoic acid (ATRA). As a result, the incidence of early hemorrhagic deaths for which APL is notorious has reduced to 5-10% as reported in clinical trials. These results are not replicated outside of clinical trials as is evident from recent population-based registries. High incidence of early hemorrhagic deaths remains the greatest contributor to treatment failure in this otherwise curable leukemia. Additionally, thrombosis is now being increasingly recognized in APL patients and may be associated with ATRA usage.