ECM2 (extracellular matrix protein 2) is a secreted glycoprotein that plays crucial roles in extracellular matrix organization and cell adhesion processes. The protein contains functional domains including an RGD sequence, von Willebrand factor domain, and leucine-rich repeats that facilitate protein-protein interactions and cell-ECM recognition 1. ECM2 demonstrates calcium-binding properties and preferentially binds to B lineage cells in a divalent cation-dependent manner, promoting lymphopoiesis by enhancing mitogen-dependent proliferation of mature B cells and pre-B cell cloning 2. The protein is predominantly expressed in adipose tissue and female-specific organs including mammary gland, ovary, and uterus 1. In disease contexts, ECM2 serves as a biomarker across multiple conditions: it is upregulated in pulmonary artery hypertension and correlates with immune cell infiltration patterns 3, acts as a prognostic indicator in lower grade glioma where high expression predicts shorter survival 4, and functions in triple-negative breast cancer suppression through ECM remodeling under HOXB2 transcriptional control 5. Additionally, ECM2 has emerged as a diagnostic biomarker for coronary artery disease, contributing to biomarker panels that can distinguish stable CAD from controls 6.