Abstract:
Objective To investigate the diagnositic performance of cardiac myosin-binding protein C (cMyBP-C) in cardiovascular immune-related adverse events (CV-irAE), and to evaluate its potential as a novel biomarker of myocardial injury.
Methods Cancer patients receiving immune checkpoint inhibitors (ICI) therapy at Zhongshan Hospital, Fudan University, from January 2025 to September 2025 were enrolled. Patients were divided into the positive group (high-sensitivity cardiac troponin T hs-cTnT≥99th percentile 14 pg/mL, n=78) and the negative group (hs-cTnT<99th percentile, n=56). A control group (n=231) consisted of cancer patients without prior anti-tumor therapy and healthy individuals. Levels of cMyBP-C, hs-cTnT, creatine kinase isoenzyme-MB (CK-MB), and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured. The screening reference value of cMyBP-C was established using the 99th percentile method. Diagnositic performance was evaluated by receiver operating characteristic (ROC) curves and area under the curve (AUC). The association between cMyBP-C level and myocardial edema assessed by cardiac magnetic resonance (CMR) was analyzed using Spearman correlation.
Results The difference in cMyBP-C levels among the three groups was statistically significant (P<0.001). Based on the 99th percentile of the control group, the screening reference value of cMyBP-C was determined to be 5.86 pg/mL. ROC curves showed that cMyBP-C achieved an AUC of 0.919 (95%CI 0.898–0.939) for detecting the risk of CV-irAE, comparable to CK-MB (AUC=0.917, 95%CI 0.896–0.939, P=0.682) and superior to NT-proBNP (AUC=0.876, 95%CI 0.850–0.902, P<0.001). After excluding non-cardiovascular adverse events, the AUC of cMyBP-C increased to 0.934, CK-MB was 0.893, and NT-proBNP was 0.877. Spearman correlation analysis revealed that among patients with ICI-associated myocarditis (n=21), cMyBP-C level was positively correlated with the extent of myocardial edema assessed by CMR ( ρ=0.64, P=0.002).
Conclusions cMyBP-C is significantly elevated in patients with CV-irAEs, demonstrating diagnositic performance comparable to or better than conventional biomarkers, and reflecting the burden of myocardial inflammation. These findings suggest that cMyBP-C may serve as a valuable complementary diagnositic biomarker for CV-irAEs.