TLR2 and idiopathic pulmonary fibrosis: Conversely, all three down-regulated co-expressed genes showed a significant negative causal relationship with IPF, namely LIN7A (OR=0.836; 95% CI:[0.701 to 0.997]; P = 0.046), PPP1R14A (OR=0.812; 95% CI:[0.673 to 0.980]; P = 0.030), and TLR2 (OR=0.580; 95% CI:[0.380 to 0.886]; P = 0.012).