Role of basement membrane in tumor growth and metastasis.

The basement membrane is a thin extracellular matrix produced by epithelial and endothelial cells. It is biologically active for normal epithelial cell differentiation. Basement membrane promotes the growth of tumor cells in vitro and in vivo when coinjected. Laminin, the major biologically active component, also increases tumor growth and the malignant phenotype by promoting increased cell growth and protease activity. Using systematic peptide screening with synthetic peptides covering the entire laminin molecule, several active sites in laminin have been identified that regulate tumor growth and metastasis.