GDF15 and posterior cortical atrophy: In the bioplots, the loading vectors of several non-PSA related candidate biomarkers, such as Tie-2, GDF-15, SDC1, B7-H7, VCAM-1 as a cluster, were at angles to those of the PSA-based biomarkers yet still pointed to the direction that would complement the PSA-based biomarkers in separating AG PCa and low risk PCa or non-PCa samples, indicating potential complementary value to the PSA-related tests.