CTHRC1 encodes a secreted glycoprotein that functions as a key regulator of tissue remodeling and fibrosis across multiple organ systems. In bone homeostasis, CTHRC1 is secreted by osteoclasts to influence osteoblast formation and differentiation 1. The protein plays a critical role in pathological fibrosis, where CTHRC1+ fibroblasts emerge as highly collagen-producing cells in fibrotic tissues. In pulmonary fibrosis, CTHRC1-expressing fibroblasts are concentrated within fibroblastic foci and represent the highest collagen-producing subpopulation 2. These cells arise through fibroblast-to-myofibroblast transition, where TGFβ1 signaling promotes the switch from transitional fibroblasts to invasive CTHRC1+ myofibroblasts 3. CTHRC1+ fibroblasts derive from alveolar fibroblasts during lung injury and contribute substantially to pathological matrix deposition 4. Beyond the lung, CTHRC1+ cancer-associated fibroblasts promote epithelial-mesenchymal transition in colorectal cancer through WNT5A signaling 5, and creeping fat-derived CTHRC1+ fibroblasts drive intestinal fibrosis in Crohn's disease 6. Clinically, CTHRC1 serves as a marker of pathological fibroblasts and represents a potential therapeutic target for fibrotic diseases and cancer progression 7.