Lee, Dae H

Importance The introduction of immune checkpoint inhibitor (ICI) therapy has improved cancer outcomes but at the cost of adverse events, mainly related to the immune system. Cardiovascular (CV) toxic effects, and especially myocarditis, are of particular concern and are the subject of this position statement by the International Cardio-Oncology Society with representation of experts from oncology, hematology, and cardiology. Observations CV toxic effects of ICI therapies include inflammation-associated diseases, such as myocarditis, pericarditis, and vasculitis, as well as the aggravation of chronic inflammatory conditions, such as atherosclerosis with acute ischemic complications (myocardial infarction and stroke). Patients taking ICI therapies can also develop cardiac dysfunction, stress-induced cardiomyopathy (Takotsubo or apical ballooning syndrome), and heart failure without inflammatory cell infiltration of the myocardium. Atrial and ventricular arrhythmias can emerge in the setting of a systemic inflammatory milieu, myocarditis, or ischemia. Of all potential CV adverse effects, myocarditis remains of highest concern, although fatality rates have declined over time with a broadening spectrum of presentations ranging from troponin elevation of uncertain significance to smoldering, nonsevere, and severe or fulminant myocarditis. Conclusions and Relevance Concerns for myocarditis continue to dominate the spectrum of CV toxic effects in patients receiving ICI therapy. Recommendations for management vary according to severity. Multidisciplinary collaborations remain key for managing acute toxic effects and future cancer treatment decisions, including ICI rechallenge. Ischemic heart disease constitutes the main differential diagnosis in these patients, while pericarditis can be concomitantly present, and atrial and ventricular arrhythmias can also complicate the clinical picture. Several gaps in knowledge are identified and require further research.

Abstract Despite advances in understanding the genetic abnormalities in myeloproliferative neoplasms (MPN) and the development of JAK2 inhibitors, there is an urgent need to devise new treatment strategies, particularly for patients with triple-negative (TN) myelofibrosis (MF) who lack mutations in the JAK2 kinase pathway and have very poor clinical outcomes. Here we report that MYC copy number gain and increased MYC expression frequently occur in TN-MF and that MYC-directed activation of S100A9, an alarmin protein that plays pivotal roles in inflammation and innate immunity, is necessary and sufficient to drive development and progression of MF. Notably, the MYC-S100A9 circuit provokes a complex network of inflammatory signaling that involves numerous hematopoietic cell types in the bone marrow microenvironment. Accordingly, genetic ablation of S100A9 or treatment with small molecules targeting the MYC-S100A9 pathway effectively ameliorates MF phenotypes, highlighting the MYC–alarmin axis as a novel therapeutic vulnerability for this subgroup of MPNs. Significance: This study establishes that MYC expression is increased in TN-MPNs via trisomy 8, that a MYC-S100A9 circuit manifest in these cases is sufficient to provoke myelofibrosis and inflammation in diverse hematopoietic cell types in the BM niche, and that the MYC-S100A9 circuit is targetable in TN-MPNs.