Tenascin C (TN-C) is a glycoprotein that in humans is encoded by the TNC gene. It is expressed in the extracellular matrix of various tissues during development, disease or injury, and in restricted neurogenic areas of the central nervous system. Tenascin-C is the founding member of the tenascin protein family. In the embryo it is made by migrating cells like the neural crest; it is also abundant in developing tendons, bone and cartilage.

Tenascin C continues to be researched as a potential biomarker for a number of diseases such as myocarditis and different forms of cancer. The numerous involvements with cellular functioning and signaling make TN-C a popular protein to study in developing new therapies and detection methods. Recent work has shown that TN-C inhibits HIV infection in immune cells by binding to a chemokine coreceptor site on the HIV-1 envelope protein, blocking the virus’ entry into the host cells.