The composition of the extracellular matrix of all vertebrates is dominated by a class of molecules known as collagens, each with a unique feature suited to its function and location. Collagens are known to have multiple functions. They are involved in tissue differentiation, morphogenesis and repair; play a role in the maintenance of tissue architecture; and form the filtration barrier of blood vessels.

Collagen Type IV is a primary component in the basal lamina that is used as a marker to observe the presence of the lamina and examine its structure. In addition to the epithelial basal lamina, Anti-Collagen Type IV stains mesenchymal components. It is useful for identifying soft tissue cancers including schwannomas and leiomyomas. Anti-Collagen Type IV frequently reacts with these tissues after becoming well-differentiated and malignant. The use of Anti-Collagen Type IV produces more reliable results than non-specific silver reticulum stains when investigating the vascular elements of neoplasms, hemangiopericytoma, angiosarcoma and epithelioid hemangioendothelioma.