Empirical-based and kernel-based ROC estimates for PSA alone (thin line) and the combined biomarker values (thick line). Left to right (i.e., scenarios (1) to (3)) for the empirical-based estimates: (AUCPSA = 0.7185, AUCC = 0.7933), (AUCPSA = 0.7347, AUCC = 0.8620), (AUCPSA = 0.6682, AUCC = 0.8342). Left to right (i.e., scenarios (1) to (3)) for the kernel-based estimates: (AUCPSA = 0.6962, AUCC = 0.7789), (AUCPSA = 0.7096, AUCC = 0.8456), (AUCPSA = 0.6537, AUCC = 0.8203).