PRL and idiopathic pulmonary fibrosis: On the basis of the existing research on IPF, the enriched KEGG pathways were divided into hormone regulation-related signaling pathways (thyroid hormone, relaxin, prolactin, and estrogen), cell growth state regulation-related signaling pathways (VEGF, PI3K/AKT, ErbB, FoxO, and HIF-1), and immune regulation-related signaling pathways (IL-17).