Keratan sulfate proteoglycan lumican, mostly known as lumican, belongs to the SLRP class II subfamily and the small leucine-rich proteoglycan (SLRP) family. Lumican binds to laminin. It has positive regulation of transcription from RNA polymerase II promoter and transforming growth factor beta1 production. Lumican is expressed in a variety of tissues, including skin, artery, lung, cornea, kidney, bone, aorta, and articular cartilage. The abnormal connective tissue phenotype seen in the Lumican null mice shows the importance of the role of Lumican in collagen fibrillogenesis. In addition to the control of collagen fibril assembly, Lumican has been shown to play a role in the regulation of cell proliferation, migration, and adhesion.