Abstract: The present invention relates to a method of predicting the risk of a subject developing a cardiovascular event, comprising determining the presence of a biomarker that is indicative of the risk of developing a cardiovascular event in an exosome sample from the subject. The exosomes are suitably isolated from a body fluid selected from serum, plasma, blood, urine, amniotic fluid, malignant ascites, bronchoalveolar lavage fluid, synovial fluid, breast milk, saliva, in particular serum. Alternatively, the exosomes are present in a body fluid, in particular serum. The biomarker is selected from the proteins Vitronectin, Serpin F2, CD14, Cystatin C, Plasminogen, Nidogen 2, Serpin G1 or any combination of two or more of these proteins. The invention further relates to a method of diagnosing the occurrence of acute coronary syndrome in a subject, comprising determining the presence of a biomarker that is indicative of the occurrence of acute coronary syndrome in an exosome sample from the subject.