CTF1 (cardiotrophin 1) is a member of the interleukin-6 cytokine family that functions as a pleiotropic signaling molecule with roles in tissue homeostasis and disease pathogenesis. CTF1 binds to and activates the IL6ST/gp130 receptor, initiating JAK-STAT3 signaling cascades 1. In physiological contexts, CTF1 promotes reciprocal tissue crosstalk: dermal papilla-derived CTF1 binds EC-expressed IL6ST to activate angiogenesis-promoting alpha-linolenic acid metabolism 2. CTF1 also functions as a neuroprotective factor, with transgenic expression improving learning and memory in Alzheimer's disease models through GSK-3β inhibition 3. In pathological contexts, CTF1 emerges as a critical oncogenic mediator. In glioma, elevated CTF1 expression correlates with malignancy, poor prognosis, and immune checkpoint activation; CTF1 knockdown suppresses proliferation and promotes apoptosis 4. In breast cancer, tumor-derived CTF1 activates fibroblast autophagy via STAT3 phosphorylation and AMPK-ULK1 signaling, promoting cancer cell migration, invasion, and lymph node metastasis 1. Genetic studies reveal that CTF1 variants associate with altered insulin sensitivity 5, while proteomic analyses identify CTF1 in the interleukin-6 pathway as relevant to Parkinson's disease pathogenesis 6. These findings position CTF1 as a therapeutically targetable node in cancer-stroma interactions and neurodegeneration.