IL6 is a multifunctional cytokine with critical roles across metabolic, vascular, and immune regulation. Functionally, IL6 acts as an essential regulator of bone homeostasis and angiogenesis through VEGF induction 12, and functions as a myokine released during muscle contraction to enhance lipolysis and improve insulin sensitivity 3. IL6 signals primarily through the IL6-GP130-STAT3 JAK2 pathway 45. The N-glycosylation status of IL6 determines downstream signaling preference: glycosylated IL6 sustains JAK-STAT3 signaling, while non-glycosylated IL6 shifts signaling toward the SRC-YAP-SOX2 axis, promoting epithelial-mesenchymal transition 5. In endothelial cells, IL6 mediates mesenchymal transition and organ fibrosis when autophagy is defective 6. IL6 is dysregulated across multiple diseases: elevated IL6 promotes brain metastasis in lung cancer via microglia polarization 4 and suppresses anti-tumor T and NK cell responses in EGFR-mutant NSCLC 7. Clinically, elevated IL6 and IL6R expression predict poor survival in colorectal cancer and associate with endometrial dysfunction in recurrent implantation failure 89. IL6 gene polymorphisms (rs1800795, rs1800796) correlate with neurological disorders including schizophrenia, Alzheimer's, and Parkinson's disease, with elevated IL6 expression associated with reduced brain cancer survival 10.