Extracellular matrix protein that seems to be a ligand for ITGA8:ITGB1, ITGAV:ITGB1 and ITGA4:ITGB1 (By similarity) (PubMed:14709716). Involved in neurite outgrowth and cell migration in hippocampal explants (PubMed:12812753). During endochondral bone formation, inhibits proliferation and differentiation of proteoblasts mediated by canonical WNT signaling (PubMed:17395156). In tumors, stimulates angiogenesis by elongation, migration and sprouting of endothelial cells (By similarity). Expressed in most mammary tumors, may facilitate tumorigenesis by supporting the migratory behavior of breast cancer cells (PubMed:15592496). Homohexamer. A number of isoforms are produced. Highest expression in kidney followed by spleen and brain. In brain, highest expression is found in hippocampus, cerebellum and olfactory bulb. Expressed in aortic valve, corneal limbus (PubMed:14709716). Expressed in ribs periosteum. During a fracture repair process, expression increases in cells of newly formed perichondrium/peristeum surrounding the cartalaginous callus (PubMed:14709716, PubMed:17395156). Hardly detectable at embryonic day (E) 14, then increases until postnatal day 17 and remains detectable in the adult (PubMed:12812753). Expressed as early as 11.5 dpc in the maxillary process until 16.5 dpc when is expressed in the newly formed mandible. At 14.5 dpc is detected in smooth muscle cells of the stomach and intestine and at 15.5, in the periosteum of the ribs. At 16.5 dpc the expression is restricted to mandible, palate and teeth (PubMed:14709716). During endochondral bone formation, first expressed at 13.5 dpc in the perichondrium. At E 16.5, detected in perichondrium and periosteum (PubMed:17395156). Belongs to the tenascin family.