Dynamic Changes in Apolipoproteins During Anthracycline Therapy: An Exploratory Study of Potential Biomarkers of Cardiotoxicity in Breast Cancer Patients

Background/Objectives: Cancer therapy-related cardiac dysfunction (CTRCD) is a clinically important complication of anthracycline-based chemotherapy, and early identification of patients at increased risk remains challenging. Apolipoproteins involved in lipid metabolism and inflammatory pathways may reflect cardiovascular alterations induced by anticancer treatment. This study aimed to evaluate changes in selected apolipoproteins and C-reactive protein (CRP) during anthracycline therapy and to assess their association with the development of CTRCD in patients with breast cancer. Methods: This prospective study included 54 patients with breast cancer treated with anthracycline-based chemotherapy at the Maria Sklodowska-Curie National Research Institute of Oncology in Warsaw, Poland. Plasma concentrations of apolipoproteins A1, A2, B, C1, C3, D, E, H, and J, as well as CRP, were measured using an xMAP multiplex assay at baseline, after completion of chemotherapy, and approximately 6 months after treatment. Cardiac biomarkers, including high-sensitivity cardiac troponin T (hs-cTnT) and NT-proBNP, were also assessed. CTRCD was diagnosed based on standard clinical and echocardiographic criteria. Results: Anthracycline therapy significantly affected the apolipoprotein profile, with decreased concentrations of apolipoproteins A1, A2, B, C1, E, H, and J, and increased concentrations of apolipoproteins C3 (ApoC3) and D and CRP during follow-up (all p < 0.001). Patients with CTRCD showed higher concentrations of selected apolipoproteins, particularly apolipoproteins C3, E (ApoE) and A2. The change in ApoC3 concentration from baseline to 6 months demonstrated the strongest predictive performance for CTRCD (AUC = 0.875; 95% CI: 0.735–1.000; p < 0.001). A cut-off value of ≥31.50 mg/dL provided 83.3% sensitivity and 87.5% specificity. Conclusions: Changes in apolipoprotein concentrations, particularly an increase in ApoC3 during anthracycline therapy, may be associated with the development of CTRCD. Assessment of ApoC3 and ApoE after chemotherapy may provide additional information for identifying breast cancer patients at higher risk of cardiac dysfunction.