Hyaluronan: a critical component of epithelial-mesenchymal and epithelial-carcinoma transitions.

Hyaluronan plays a central role in the transition of epithelia to mesenchyme in the embryo and in the acquisition of transformed properties in carcinoma cells. In some cases, hyaluronan is both essential and sufficient for induction of epithelial-mesenchymal transitions (EMTs). Underlying its role are the effects of hyaluronan on receptor kinase activities, cell survival pathways, and multidrug transporters. A more complete understanding of the mechanisms whereby hyaluronan exerts its influences on cell behavior will enhance our understanding of normal and pathological EMTs and may lead to improved therapies for cancer patients.