The DRG Cyr61 ELISA is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of Cyr61 in serum, plasma and urine.For Research Use Only (RUO)CCN1/Cyr61 as a member of growth factor inducible immediate-early genes belongs to CCN family. Other members of the CCN family include CCN2 (connective tissue growthfactor, CTGF), CCN3 (nephroblastoma-overexpressed, NOV), CCN4 (Wnt-inducible secreted protein-1, WISP-1), CCN5 (WISP-2), and CCN6 (WISP-3). The CCN1/Cyr61 protein is composed of four conserved modular domains that share sequence similarities to insulin-like growth factor-binding proteins, von Willebrand factor type C repeats, thrombospondin type 1 repeats, and carboxylterminal region containing cysteine knot domains, respectively (1). CCN1/Cyr61 regulates cell proliferation, adhesion, migration, differentiation, apoptosis, growth arrest and extracellular matrix production (2). Increasing evidence demonstrates that aberrant expression of CCN1/Cyr61 is linked to tumorigenesis (3). Cyr61 may contribute to the malignant progression of gastric cancer by promoting tumor cell motility/invasion through up-regulation of the functional COX-2 via an integrin avh3/NF-nB-dependent pathway (4). Increased expression of CCN1/Cyr61 is also detected in rhabdomyosarcoma, colon adenosarcoma, papilloma of bladder, and multiforms of glioblastoma as well as in several types of pediatric tumors (5). Moreover, Cyr61 is overexpressed in 70% of breast cancer patients with infiltrating ductal carcinoma (6,7) In contrast, earlier reports reveal that downregulation of CCN1/Cyr61 expression is noted in prostate cancer, uterine leiomyoma, embryonic rhabdomyosarcoma, and non-small-cell lung carcinoma (5).The DRG Cyr61 ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle. The microtiter wells are coated with a monoclonal[mouse] antibody directed towards a unique antigenic site of the Cyr61 molecule. An aliquot of patient sample containing endogenous Cyr61 is incubated in the coated well with assay buffer and enzyme conjugate, which is a rabbit anti-Cyr61 polyclonal antibody. After incubation, the unbound conjugate is washed off. Finally, Enzyme Complex, which is a goat anti-rabbit antibody conjugated with horseradish peroxidase, is added, and after incubation, unbound enzyme complex is washed off. The amount of bound peroxidase is proportional to the concentration of Cyr61 in the sample. Having added the substrate solution, the intensity of colour developed is proportional to the concentration of Cyr61 in the patient sample.