Embracing cancer complexity: Hallmarks of systemic disease.

The last 50 years have witnessed extraordinary developments in understanding mechanisms of carcinogenesis, synthesized as the hallmarks of cancer. Despite this logical framework, our understanding of the molecular basis of systemic manifestations and the underlying causes of cancer-related death remains incomplete. Looking forward, elucidating how tumors interact with distant organs and how multifaceted environmental and physiological parameters impinge on tumors and their hosts will be crucial for advances in preventing and more effectively treating human cancers. In this perspective, we discuss complexities of cancer as a systemic disease, including tumor initiation and promotion, tumor micro- and immune macro-environments, aging, metabolism and obesity, cancer cachexia, circadian rhythms, nervous system interactions, tumor-related thrombosis, and the microbiome. Model systems incorporating human genetic variation will be essential to decipher the mechanistic basis of these phenomena and unravel gene-environment interactions, providing a modern synthesis of molecular oncology that is primed to prevent cancers and improve patient quality of life and cancer outcomes.

Hypoxia shapes the immune landscape in lung injury and promotes the persistence of inflammation.

Hypoxemia is a defining feature of acute respiratory distress syndrome (ARDS), an often-fatal complication of pulmonary or systemic inflammation, yet the resulting tissue hypoxia, and its impact on immune responses, is often neglected. In the present study, we have shown that ARDS patients were hypoxemic and monocytopenic within the first 48 h of ventilation. Monocytopenia was also observed in mouse models of hypoxic acute lung injury, in which hypoxemia drove the suppression of type I interferon signaling in the bone marrow. This impaired monopoiesis resulted in reduced accumulation of monocyte-derived macrophages and enhanced neutrophil-mediated inflammation in the lung. Administration of colony-stimulating factor 1 in mice with hypoxic lung injury rescued the monocytopenia, altered the phenotype of circulating monocytes, increased monocyte-derived macrophages in the lung and limited injury. Thus, tissue hypoxia altered the dynamics of the immune response to the detriment of the host and interventions to address the aberrant response offer new therapeutic strategies for ARDS.

Phosphoinositide 3-Kinase δ Inhibition Improves Neutrophil Bacterial Killing in Critically Ill Patients at High Risk of Infection.

Acquired neutrophil dysfunction frequently develops during critical illness, independently increasing the risk for intensive care unit-acquired infection. PI3Kδ is implicated in driving neutrophil dysfunction and can potentially be targeted pharmacologically. The aims of this study were to determine whether PI3Kδ inhibition reverses dysfunction in neutrophils from critically ill patients and to describe potential mechanisms. Neutrophils were isolated from blood taken from critically ill patients requiring intubation and mechanical ventilation, renal support, or blood pressure support. In separate validation experiments, neutrophil dysfunction was induced pharmacologically in neutrophils from healthy volunteers. Phagocytosis and bacterial killing assays were performed, and activity of RhoA and protein kinase A (PKA) was assessed. Inhibitors of PI3Kδ, 3-phosphoinositide-dependent protein kinase-1 (PDK1), and PKA were used to determine mechanisms of neutrophil dysfunction. Sixty-six patients were recruited. In the 27 patients (40.9%) with impaired neutrophil function, PI3Kδ inhibition consistently improved function and significantly increased bacterial killing. These findings were validated in neutrophils from healthy volunteers with salbutamol-induced dysfunction and extended to demonstrate that PI3Kδ inhibition restored killing of clinical isolates of nine pathogens commonly associated with intensive care unit-acquired infection. PI3Kδ activation was associated with PDK1 activation, which in turn phosphorylated PKA, which drove phosphorylation and inhibition of the key regulator of neutrophil phagocytosis, RhoA. These data indicate that, in a significant proportion of critically ill patients, PI3Kδ inhibition can improve neutrophil function through PDK1- and PKA-dependent processes, suggesting that therapeutic use of PI3Kδ inhibitors warrants investigation in this setting.

Myeloproliferative Neoplasms in Children and Adolescents and Thrombosis at Unusual Sites: The Role of Driver Mutations.

Myeloproliferative neoplasms (MPNs) in childhood and adolescence are rare and seldom complicated by thrombosis. We describe 3 cases of thrombosis at unusual sites in young patients with MPNs. In the pediatric MPN population, unlike in adult MPNs, a clonal mutation is identifiable in only a minority of cases (22% to 26%). All 3 of these individuals had JAK2 mutations driving the disease process. A literature search identified 19 cases of MPN-associated thrombosis in children. Seventeen of the 19 children (89.5%) had a driver mutation. These cases suggest that identifiable driver mutations may confer an increased thrombotic risk in children with MPNs.

Tissue factor expression in monocyte subsets during human immunothrombosis, endotoxemia and sepsis.

INTRODUCTION: Tissue factor expression on monocytes is implicated in the pathophysiology of sepsis-induced coagulopathy. How tissue factor is expressed by monocyte subsets (classical, intermediate and non-classical) is unknown. METHODS: Monocytic tissue factor surface expression was investigated during three conditions. Primary human monocytes and microvascular endothelial cell co-cultures were used for in vitro studies. Volunteers received a bolus of lipopolysaccharide (2 ng/kg) to induce endotoxemia. Patients with sepsis, or controls with critical illness unrelated to sepsis, were recruited from four intensive care units. RESULTS: Contact with endothelium and stimulation with lipopolysaccharide reduced the proportion of intermediate monocytes. Lipopolysaccharide increased tissue factor surface expression on classical and non-classical monocytes. Endotoxemia induced profound, transient monocytopenia, along with activation of coagulation pathways. In the remaining circulating monocytes, tissue factor was up-regulated in intermediate monocytes, though approximately 60 % of individuals (responders) up-regulated tissue factor across all monocyte subsets. In critically ill patients, tissue factor expression on intermediate and non-classical monocytes was significantly higher in patients with established sepsis than among non-septic patients. Upon recovery of sepsis, expression of tissue factor increased significantly in classical monocytes. CONCLUSION: Tissue factor expression in monocyte subsets varies significantly during health, endotoxemia and sepsis.

Practical treatment guidance for cancer-associated thrombosis - Managing the challenging patient: A consensus statement.

Cancer-associated thrombosis (CAT) is a leading cause of death amongst people with cancer. Treatment decisions have become increasingly complex with the introduction of direct oral anticoagulants and existing guidelines are limited to evidence from patients meeting stringent trial-entry criteria. To assist decision making for healthcare professionals managing CAT in challenging 'real-world' situations, an expert working group of clinicians from oncology, haematology and pharmacology convened over a series of virtual meetings between September 2020 and January 2021 to catalogue the most challenging clinical problems and define consensus recommendations. Clinical problems were divided amongst the group members according to their areas of expertise, with each reviewing the literature and writing their recommendations. Using a web-based file-sharing platform, each contribution was reviewed until consensus was reached. Each clinical problem is discussed; these include managing gastrointestinal impairment, renal impairment, liver impairment, increased risk of bleeding, extremes of body weight, drug interactions, anticoagulation beyond the initial six months and managing recurrent thrombosis. A user-friendly, practical, colour-coded algorithm was produced to help guide clinical decision-making in CAT. Red highlights decision steps where shared decision making, such as with the multi-disciplinary team, is recommended. Amber steps reflect uncertainty of existing evidence. Multiple amber steps per patient warrant increased caution. Making anticoagulation decisions in people with cancer is challenging; it is important that healthcare providers can discuss where there is a lack of evidence and ensure that patient preference is given priority. This algorithm and consensus recommendations are a useful tool to guide these complex discussions.

Decision-Making with D-Dimer in the Diagnosis of Pulmonary Embolism.

The measurement of D-dimer can provide useful information to aid in the diagnosis of patients with suspected venous thromboembolism. D-dimer measurement in conjunction with adequate estimation of pretest probability can facilitate the safe discharge of patients with suspected pulmonary embolism and limit unnecessary investigation or anticoagulation. We review clinical decision-making strategies in the diagnosis of pulmonary embolism and propose means to minimize diagnostic error that might arise from knowledge of the D-dimer result prior to clinical assessment.

Spontaneous tumour lysis syndrome secondary to the transformation of chronic myelomonocytic leukaemia into acute myeloid leukaemia.

A 78-year-old man, with a 6-year history of stable chronic myelomonocytic leukaemia (CMML), presented with general deterioration and worsening pancytopenia. Bone marrow biopsy showed that his disease had transformed into acute myeloid leukaemia (AML). He was started on a supportive transfusion regimen and did not receive any chemotherapy or corticosteroids. Several weeks later, he developed acute renal failure and was admitted to a medical admissions ward. Spontaneous tumour lysis syndrome (sTLS, grade 1) was diagnosed, as per the Cairo and Bishop criteria. He was treated with intravenous fluids, rasburicase and allopurinol. His renal function improved and he recovered from the sTLS. The authors believe that this is the first published case of sTLS occurring as a result of CMML transforming into AML; it highlights the importance of recognising sTLS as a cause of renal failure and electrolyte disturbance before cancer treatment begins.