These results suggested that extracellular proteins, such as transporter proteins, metabolic process proteins, immune system process proteins, developmental process proteins and localization-related proteins, biological regulation-related proteins and reproduction-related proteins, and intracellular proteins like cell-part proteins and membrane proteins more likely tended to be expressed in depression and the molecular function of the proteins mainly related to the metabolism function of liver. Here, PROS1 is linked to major depressive disorder.