GDF15 and posterior cortical atrophy: All 42 selected genes were first tested by univariate logistic regression analysis, with 7 genes (PCA3, ELF3, HIST1H2BG, MYO6, GALNT3, PHF12 and GDF15) showing significant association for discriminating PCa patients from control individuals (Table 2 and Additional file 2: Table S2).