FKBP4 and major depressive disorder: Fifteen of the proteins we detected (carbonyl reductase [CBR1], dihydropyrimidinase-like 2 [DPYSL2], EF-hand domain family, member D2 [EFHD2], FK506-binding protein 4 [FKBP4], GFAP, GLUL, HSPA8, NEFL, NEFM, phosphoglycerate mutase 1 [PGAM1], PRDX6, SELENBP1, VIM, 14-3-3 protein eta [YWHAH] and 14-3-3 protein zeta/delta [YWHAZ]) have already been suggested as potential biomarker candidates for depression or schizophrenia [66], [67], [68], [69], [70], [71], [72], [73].