LPAR4 is a G protein-coupled receptor for lysophosphatidic acid (LPA) that transduces signals through increased intracellular calcium and adenylyl cyclase activation. In cancer biology, LPAR4 is stress-responsive and plays a critical role in tumor initiation; pancreatic cancer cells upregulate LPAR4 in response to isolation stress or chemotherapy via downregulation of miR-139-5p, promoting drug resistance and self-renewal through an LPAR4/AKT/CREB axis that enhances fibronectin production 1. In cardiac development, SOX17-mediated LPAR4 expression is essential during pluripotent stem cell-derived cardiac differentiation and cardiac regeneration following myocardial infarction; p38 MAPK inhibition of LPAR4 signaling early after MI improves cardiac repair and reduces fibrotic scarring 2. LPAR4 regulates bone homeostasis by suppressing osteogenic and promoting adipogenic differentiation of mesenchymal progenitor cells through inactivation of RhoA/ROCK1/β-catenin signaling 3. In tissue fibrosis, miR-139-5p targeting of LPAR4 inhibits epithelial-mesenchymal transition via PI3K/Akt suppression 4. LPAR4 is significantly upregulated in pancreatic ductal adenocarcinoma tumor fibroblasts 5 and ovarian endometriotic cysts 6, where it acts as a key mediator of pathological LPA signaling. These findings establish LPAR4 as a versatile therapeutic target across cancer, cardiac disease, bone metabolism, and fibrotic pathologies.