In a recent study serglycin was found to be among the most abundantly expressed proteins in adipocytes of epicardial adipose tissue in patients with coronary artery disease (CAD). It was demonstrated that TNFα induces expression and secretion of serglycin in adipocytes. Circulating serglycin might also participate in the mechanism of systemic vascular insult and atheromatous change. Serglycin is a dominant intracellular proteoglycan expressed by immune cells, where it interacts with numerous inflammatory mediators, such as proteases, chemokines, cytokines, and growth factors. Serglycin is implicated in their storage into the granules and their protection since they are secreted as complexes and delivered to their targets after secretion. Serglycin secretion can be induced in several cell types upon external inflammatory stimulation. The biosynthesis of serglycin is up-regulated by lipopolysaccharide (LPS) in macrophages, tumor necrosis factor (TNF) in endothelial cells and adipo¬cytes and interleukin 1b (IL-1b) in smooth muscle cells. Another interesting implication of serglycin in the regulation of immune system is its ability to inhibit complement system activity. Serglycin is also involved in apoptosis and immune regulation. Mast cells lacking serglycin expression preferentially died by necrosis rather than apoptosis. Serglycin has been shown to be a biomarker of acute myeloid leukemia (levels are higher than in acute lymphoblastic leukemia patients). Invasive nasopharyngeal carcinoma (NPC) cells secrete higher levels of serglycin and expression is elevated in NPC cells with higher metastasis potential. Serglycin is also highly expressed in breast cancer tissues and by an aggressive breast cancer cell line.