PAK1 and idiopathic pulmonary fibrosis: Using the expression profile of three independent prognostic factors and multivariate analysis coefficients, we assessed the risk score of each IPF sample and developed a novel prognostic risk model, represented by the CRG score formula: CXCR4 * 2.68 + GPR56 * 2.95 + PAK1 * 4.57.