ERAP2 and pancreatic adenocarcinoma: The formula for the risk score of every PAAD patient was constructed: risk score = (expression value of KIF23 * 0.394) − (expression value of BIN1 * 0.098) + (expression value of LAPTM4A * 0.005) + (expression value of ERAP2 * 0.051) − (expression value of ATP8B2 * 0.082) − (expression value of FAM118A * 0.081) + (expression value of RGS16 * 0.014) − (expression value of ELOM1 * 0.112) + (expression value of RAPGEFL1 * 0.017).