['The regions of ruptured atherosclerotic plaques have numerous macrophages. Osteopontin that modulates macrophage function has been shown in atherosclerotic plaques. We aimed to study the plasma levels of osteopontin in patients with unstable angina or non-ST-seg ment elevation myocardial infarction (NSTEMI) and the rela tionship between osteopontin and the extent of the coronary artery disease (CAD).', 'We studied 65 patients with unstable angina or NSTEMI, 25 patients with stable angina and 18 patients as the control group. The extent of coronary artery stenosis was determined by the number of vessels with >50% stenosis. Plasma osteopontin concentrations were measured from the blood samples that were drawn immediately after admission to the emergency department in unstable angina/NSTEMI patients and before the coronary angiograph in the stable angina and control groups.', 'The plasma osteopontin concentration was (495 118 ng/ml) significantly higher in the patients with unstable angina/NSTEMI compared to the stable angina group (319 106 ng/ml) and control group (125+/-54 ng/ml) (p=0.0001 The plasma osteopontin levels were lower in the patients with stable angina pectoris who had one-vessel disease compared to those with two-vessel disease (p=0.01). How ever, in the unstable angina/NSTEMI group, the plasma osteopontin levels were statistically not different among the patients with one-vessel, and two-vessel and three-vessel disease (p=NS). There was no correlation between the plasma osteopontin levels and the extent of coronary stenosis.'] Are plasma osteopontin levels elevated in non-ST-segment elevation acute coronary syndromes?